Video: What are I-frames and why do they affect the size of the video? Videos usually are described by a set of parameters including: bit rate, frame rate, width & height.

But I came to realize that there are more parameters including B-frames and I frames (or I guess they are the KEY-FRAMES).

Now I noticed that they exist when I was working on a custom video capturing technique in which I have the ability to control how often they appear in terms of seconds, so they are either 1 sec away from each other or 2 sec away or 3.....

But some weird things happened when I tried to change the appearance of these frames.

First case:

When I encoded a video with (2 sec or 1 between I Frames) I got a video that doesn't seek well.

Now If I try to merge the encoded video with an equal length audio file for some reason when I seek forward or backward I see black screen before I seek to the requested frame.

Second case:

When I encoded a video with (0 sec between I frames) I got a video that seeks fine, but for some reason the size increased.

Now if I try to merge the encoded video with audio of equal length I get a video mixed with audio that works well and seeks well with no black screen on seeking.

Question:

What are I frames?

Why do they affect seek behavior?

Why do they affect the merging of video with audio?

Why do they affect the size of the video?

Thanks.

You should do some research about GOPs ( Group of Pictures ) to find the definition of I frames.

This will answer the second and fourth question as well.

In generall, the more I frames a GOP has:

the better is the seeking qualitiy. (If the seek lands to a non I frame, it takes ressources to calculate the frame. To avoid this, sometimes seeking is only possible from one I frame to another)
the bigger is the video ( as I frames are saved as full frames )

The GOP has usually no effect on sound, but the codec does.


Create quickly alternating clips in Premiere Pro I'm putting together a scene with music that has a steady beat, and then the tempo increases to the point where the beat is far more rapid.

I'd like to alternate between video clips on every beat. I can do this by slicing up one clip and have it on a higher track than the other, but that becomes tedious with the amount of times it need to be done and how small some clips need to be because of the tempo increase.

Here's an example from around 2:40 here

So my question is, is there any way to accomplish this in a simple fashion? I'm not sure if I can do this in After Effects, but if I can, I'm willing to.

Thanks

I would imagine that the music video you posted used manual edits to achieve that effect. However, there are a few automated beat detection utilities out there which you might like. One After Effects / Premiere plugin specifically dedicated to beat detection and music is Mamoworld's Beat Assistant. I haven't used the plugin (cost ~$40), but it should work with Premiere or After Effects. You can see a video tutorial and overview here.

For other ideas, Premiere Elements (but not Pro) does have a built-in beat detection feature. You could also investigate Trapcode's Sound Keys plugin, which might help you  more quickly place markers on beats by hand. If you can make cuts based on loudness of the music (as opposed to beats), you may be able to use the "Convert audio to keyframes" keyframe assistant.

Unfortunately, I'm not sure if beat detection tools will be able to easily / perfectly recognize an accelerando or tempo increase like you describe. You may be stuck doing some manual editing to at least identify the beats. Using Premiere's "Add clips to a sequence automatically" could speed up your workflow when it comes time to assemble the clips in place.


Puppet tool - how do I make the arms stay attached to the same points on the body? Trying to make following character's body wiggle a bit, using the puppet tool:

The face and arms are on separate layers as they will need to move independently. When the body moves via the puppet pins, the face and arms stay in their original positions. How can I 'attach' them to their assigned positions on the body?

If you put a puppet pin at the point where the arms attach, then you can tie the position of the arm layer to the position of the puppet pin using an expression. This will attach the layer to the puppet pin, allowing you to move the pin and the layer it is on and have the arm follow.

It's easy to do, with no knowledge of scripting really required.

So say your body layer is called "Body" and it has a puppet pin called "L_Shoulder", which is on the body at the point where you want to attach the left arm. The left arm layer should have its anchor point at the point that you want it to pivot on, which coresponds to the L_Shoulder on the body layer.

Here's what you do:

First, make the arm layer a child of the body.
Now apply an expression to its position property (hit alt/opt and click on the stopwatch).

The expression we want is this:

thisComp.layer("Body").effect("Puppet").arap.mesh("Mesh 1").deform("L_Shoulder").position

This looks very difficult to type, but fortunately we don't have to. Next to the expression editor text box is a pickwhip, that we can use to select properties and values. After you alt/option-click the stopwatch, drag the pickwhip to the position property of the puppet pin, and it will fill it all in for you.

Because the puppet pin positions are relative to the layer this works well. As the arm is a parent of the child, setting its position relative to the body layer is exactly what you want.

If the arm is not a child of the body it gets much more complicated: you have to use the toComp method of the body layer to get the relative position of the pin to the composition space, and then you have to apply expressions to link the other transformation properties of the body layer, but it can be done.


How to put this video effect of switching from one scene to another very rapidly? In many music videos, for example in T.I. feat. Lil Wayne - Wit Me music video from 1:14 - 1:17, u can see the video effect where the video switches from one scene to another very, very rapidly, syncing with that instrument/beat, what is this video effect called and how to put this video effect?

In a nutshell: put one clip on top of another, and use transparency (or opacity) property to show / hide bottom video. For example, in Sony Vegas Pro you can use Composite Level envelope (there is also an extension to do it quickly). I am sure that other NLEs have similar tools.


After Effects renders with no audio I've been using after effects cs6 to make intros in my youtube template. They always render without sound. I've been exporting them as avi files. I'm currently making one in an mpeg4 format (assuming that is another name for mp4) since my other intros all have sound and they're mp4 files.

I clicked "lossless" in the render queue and I changed the file format to avi. I checked "audio output" and didn't touch the settings inside that submenu and then I clicked OK and render. after waiting a while, AE spit out an intro file thats around a gigabyte in size and has no sound. What is the problem?

The output file doesn't have any sound because there is no audio in the timeline that you are rendering.

The output format (MP4 vs. AVI) doesn't have any effect; both formats can contain an audio track or not. Checking the box to output audio only has any effect if there is already an audio track in the timeline. If there's no audio track, the output will have audio but it will be silent (as you're experiencing).

The solution is to add some audio file(s) to the project and then put it into your timeline.


Searching for video converter that maintains folder structure I'm searching for video converter software that maintains folder structure. I have a lot of videos that store to their respective folder, but what I want is to convert the entire folder and subfolders and the output path will remain the same.

Most decent encoders with watch folder support have an option to automatically encode to the same folder structure that the source came from.  I'd check the listing of any software you are looking at to see if it supports it or try a demonstration copy.  I know that Adobe Media Encoder does.

Beyond that level of detail, this is a product recommendation question which is off topic since software may or may not be available tomorrow and the options for video conversion software change frequently.


How to stream video with delay I need some kind of rtsp buffer to delay video. I have a live cam and i need to start recording video on some event. But I need 10-15 seconds before that event too. Idea is to read from camera, use the delay buffer and stream delayed video to another port. Then to start recording from delayed stream on event. So i tried VLC but it can delay displayed video :sout-display-delay=15000 as mentioned here, and NOT the streamed one :sout-delay-id=1 :sout-delay-delay:15000 (Using VLC 1.1.9 cause VLC 2.2.1 breaks if you only mention delay :( )

I used this command for example

vlc -vvv rtsp://10.0.0.5:554/live.sdp :sout=#duplicate{dst=rtp{sdp=rtsp://:8554/live.sdp},delay-id=0,delay-delay=15000} :sout-keep

Any other thoughts, applications, experiences?

Ivan

You could try using OBS streaming software (which is free), and then check out this tutorial for how to add delay to your stream. Basically you go into the advanced settings of OBS and go to the delay settings. There you can choose to add a delay of your choosing.

You can also record from the software too. Hope that helps.


Can i do decimal custom speeds in final cut pro? I want to speed a video up by a 102.4% in final cut pro, is this possible?

Yes...
Select the clip you want to speed up. Then hit Command-R (or “Modify” > “Retime” in the Menu bar) and the clip will get a green retime bar on top. Click in the little arrow down next to the percentage and choose “Custom” (or “Custom Speed” in the Menu bar).
Lastly enter your desired percentage or duration.


How to find videos that have free reuse license types on the web? Google Image Search provides a very handy method for isolating specific license types:

Is there anything like this for videos?  I've been shooting blanks so far...

You can do this is on YouTube by adding a filter under the "Features" header. E.g.:

Also found that Vimeo offers similar search functionality when you add filters on the right:

Specifically on Vimeo these each mean:

CC0: Public Domain Dedication
CC BY-NC-ND: Attribution Non-Commercial No Derivatives License
CC BY: Attribution License
CC BY-NC-SA: Attribution Non-Commercial Share Alike License
CC BY-NC: Attribution Non-Commercial License
CC BY-SA: Attribution Share Alike License
CC BY-ND: Attribution No Derivatives License


Animate variable inside expression In After Effects, I created a shape layer, added a path to that, edited the expression of it to contain
var path = thisProperty;
var cx = 100;
var cy = 200;
var r1 = 300;
var ratio =  20;
var quality = 30;
var closedPath = true;
var allPoints = new Array();

for (var a = 0; a < 360; a++) {
    var theta = degreesToRadians(a);
    x0 = Math.cos(theta);
    x = cx + r1 * x0;
    y = cy + 0.75 * r1 * (Math.sin(theta) - Math.sqrt(Math.abs(x0)));
    allPoints.push([x,y]);
}
path.createPath(allPoints, [], [], closedPath);

and added a stroke and a fill to the shape layer and set the width of the stroke to 10 and the color of the fill to light red. I got this shape as a result.

Now, I want to animate the end point of that stroke, you may see that I am looping the variable a from 0 to 360. That 360 value represents the end angle of the shape and I would like to have it animated to make an animation that "draws" the heart.
How do I animate the end value?
Is there a way to add a "dummy effect" so I can use it like
var a_max = effect("dummy")("endpoint")

Press the triangle marked "Add" next to the Contents of your shape layer.
Add a "trim path"
Add a keyframe to the "End" parameter of 0%.
Move along your timeline.
Add another keyframe of 100%.

Your path will draw on.
You probably don't want to fill it until it is drawn.


Software to Trim a Video into Multiple Files I am coming from the good old Times from GoPro Studios(discontinued),
Go Pro Studio had a feature I really loved:
To Precut your Videos into Multiple Parts and Naming them Seperatly.
Because Having Hour Long Files on your System is quite a Wastage of Space.
Also, the Ability to go Back and find All Clips Already Trimed and Named was Really Helpful.
Now I'm looking for an Alternative that can:

Trim one Video into Multiple Files (ideally with a single Watch true
Selecting Parts with Shortcut I/O without the need to Stop Every Time
to Export it Manually)

The Ability to Name the Trimmed Videos

No or little Quality Loss

It Should be Free to Use (No Watermark etc...)

Optional Export Queue to do the Time Heavy Stuff while I do something else...

What are you using for Cutting down your Videos?
What I already looked tried but couldn't find the Feature I was looking for:

Avidemux
Hit Film Express
Quick
Bandicam (Would be quite Okay but quite Expensive)
Shotcut

If I missed a way to do it in the one Above feel free to point me to it.
Thanks for your Help!

Now I'm looking for an Alternative that can:

Trim one Video into Multiple Files (ideally with a single Watch true Selecting Parts with Shortcut I/O without the need to Stop Every Time to Export it Manually)

In the light of not fully understand the "a single Watch true Selecting Parts with Shortcut I/O", my suggestion would simply happens on ffmpeg, i.e
ffmpeg -i input.mp4 -ss <start-time> -t <duration> part1.mp4

The Ability to Name the Trimmed Videos

The ffmpeg handles it nicely

No or little Quality Loss

You may consider the option -codec:v option or more options

It Should be Free to Use (No Watermark etc...)

FFMPEG is free.

Optional Export Queue to do the Time Heavy Stuff while I do something else...

scripting could help


FCPX Libraries - Smart Folder (Mac OSX) Is there a way to create a Smart Folder that contains just FCPX Libraries (.fcpbundle)?

Not sure what parameters to use for the 'Kind is Any' or 'Name Contains' search fields.

Thanks

You can choose "Kind" and set it to "Other" then type "Final Cut Pro Library" into the text field. Like this:


How can encode video with images like these [overlay a video over a fixed image] with ffmpeg? How can I use ffmpeg to composite a video image with a still image to create a final image such as the one below (where the video image "plays" on the large screen and the still image creates the illusion of a theatrical audio environment)?

Asked and answered : How can encode video with images like these (overlay a video over a fixed image) with ffmpeg?

But you want to add coordinates to the movie file to scale to a specific area.

For the perspective/scale:
https://ffmpeg.org/ffmpeg-filters.html#toc-perspective

For the overlay:
https://ffmpeg.org/ffmpeg-filters.html#toc-overlay-1


What equipment is required to record game play and commentary and post to YouTube? My son would like to record game play on PS3 (Minecraft, Lego) and overlay his own commentary and upload these videos to his channel on YouTube? What hardware, software and/or dedicated equipment is required to achieve this?

Assuming that you're looking for a low cost option, the key words you need to Google are "HDMI HD GAME Capture" which will result in hardware like this HD 1080P Video Capture HDMI Recorder with SD Card Slot for XBox 360 One PS3 PS4

The HDMI pass-through function guarantees smooth HD gaming
experience even while recording.
Record 1080P HD video into USB    disk or SD card directly, no PC required.
Supports all video sources input: HDMI, component, composite.
Pass through 1080P HDMI to display on big screen.
Record your voice with video together through microphone input.

£55 + shipping...bargain - and doesn't hog your PC whilst recording.

That should be all you need but, if further editing is required, google some free video editors to try out or you can perform basic trim and edits on YouTube...here's how.


Warp points binding in After Effects I need to do an effect In After Effects, and this it: Imagine I have a video of a dotted ball and another one with a talking mouth.
I want the ball have the talking mouth, but in way that whenever the ball opens and closes the mouth, the texture of the ball streching accordingly.

What I tried so far:
Created a mask on the mouth video.
Tracked and saved the motion of the upper and bottom lips into null objects.
Now I need an effect similar to Distort/Mesh Warp which is able use my saved motion on the ball (by binding to my null object as a parent).
I hope you understand what I'm trying to say.
Thanks in advance,
Mate

If you haven't found it yet, the Puppet tool likely what you're looking for.  You will create specific anchor points and you can keyframe their motion.

There's several tutorials out there for the right way to use the tool, but the best advice I can offer is to just play with it till you get the desired effect.

Personally I put more points where I DONT want it to move and use fewer points where I do.    To practice just create a solid and drop points on it, then grab a point and start moving it around.   It will become clear.


Are there any red filters that fit an SJ4000 Are there any red filters to fit the SJ4000 camera? Is is possible to use one compatible with a gopro hero 3?

there is a german speaking website that sells sj4000 fitting red and magenta filters if you are still searching:

http://www.magic-filter.de/artikelliste/gruppe/id-004-produkte-fuer-qumox-sj4000.html


High resolution recording with component cable I am using a HD Video Camera with a max resolution of 1920x1080. It is a Canon Legria HF M32.

I would like to record the videos using my PC. I have a component cable to USB adapter. My problem is the max resolution this allows me to record at is roughly 700x500.

Is there a way to record at a higher resolution on my PC?

If you are actually using a component cable (3 or 5 connectors with 2 more for audio) then you should be able to do HD signals unless your capture device or source device is limiting you.  Based on the SD resolution limit, it sounds like you may actually be using a composite cable though (1 yellow cable for video and a white and red cable for audio).  Composite cables only go up to SD resolution (more accurately 720 by 480 for NTSC and I forget the exact resolution for PAL but it is 576 horizontal lines.)

If you want to record HD videos using your PC you will need an actual HD capture device.  I'd personally recommend going with something HDMI based since your camera supports HDMI out.  This would prevent quality loss from going to analog and back to digital (component video cables are still analog).  Such devices aren't super cheap though.  Devices like the Black Magic Intensity or Matrox MX02 will handle your needs, but they are in the $200 price range.


Exclude audio from time remap I am working on a project, I have separate a audio layer and a video layer (with the audio muted) and I have applied time remapping to the video layer. The issue is now that whenever the video slows down or speeds up the audio also slows down and speeds up along with it. I want to know how to keep the audio speed default without the time remap affecting it.

I would duplicate the layer before applying time remapping (cmd+D).
Then only apply the time remap to one of the two layers.
Switch off the eyeball on the layer for audio (and make sure the loudspeaker icon is still enabled)
Switch off the loudspeaker icon on the layer with the time-remapping applied to it.


How to change value when passing marker with certain comment I wanted to change one value when marker with certain comment starts. I've tried something like this, but it doesn't work.
if (marker.comment("R1 L1").time > time){
  value = 40;
}

You need to check how expressions work. An expression sets the value of a property with the first line that returns a value. So for example an expression could just be:
40

since that line returns the value 40. The second line in your expression value = 40 does not return a value, it attempts to set the value property to 40, which doesn't work, because value is read-only.
What you need to do is return 40 if the time is after the marker, and if not return the current value, thus:
if (marker.comment("R1 L1").time > time){
  40;
} else {
  value;
}

Or more tersely, using ternary notation, which uses the form (condition)? <value if true> : <value if false>, thus:
(marker.comment("R1 L1").time > time)? 40 : value


Is it possible to select particular portion of a video in adobe premiere pro?, Im a beginner to video editing, kindly help me to select (free select, as like in Adobe Photoshop) particular portion of a video, to merge with another video?

If the element you need to put on the video doesn't move and the shot you are putting it in doesn't move, the best bet is to actually use Photoshop to extract the object you want to place in another video and put it in a file format that supports a transparent background (TGA, PSD, etc.)  You can then import it to Premiere and place the image wherever you want in the frame using the Motion effects settings to define the size and placement.

If the video you are placing it in is not stationary, then it will be necessary to perform motion tracking on the video you want to place the image within.  This is much more complicated and is generally done in something like After Effects.


Good alternatives to Omnidazzle? Does anyone know of a good pen software that allows you to draw on the screen? kind of similar to omnidazzle ?

here are couple of sites you should check out:

1.http://epic-pen.com/

2.http://ink2go.org/

3.https://www.pencilkings.com/drawing-tools-and-drawing-software/

hope it helps, good luck!


Why reencode MP4 to MOV for "easy post processing"? On this page author reencodes MP4 from GoPro to MOV for "easy post processing". Why the processing becomes easier after that? The author also uses -sameq flag which is gone from ffmpeg without the explanation about what it did for H.264 blocks.

On this page author reencodes MP4 from GoPro to MOV for "easy post processing". Why the processing becomes easier after that?

The author provides no explanation and does not go into any detail of what he means by "post processing". What we know:

The author's ffmpeg command is using the encoder mpeg4 which will output MPEG-4 Part 2 video (like the old Xvid video).
The format of the GoPro video is probably H.264.

We must assume that the author believes H.264 is slower to decode than MPEG-4 Part 2 video, but that is not necessarily true. Or perhaps he believes that MOV container has some advantage over MP4 container when used with these formats; I can't guess what the supposed advantages would be since the containers are so similar.

  The author also uses -sameq flag which is gone from ffmpeg without the explanation about what it did for H.264 blocks.

-sameq does not mean "same quality" (1)(2). The author's prodigious use of -sameq indicates that he doesn't really know what he is doing.

For H.264 specifically, when this option was still around (ages ago) it should have never been used when outputting H.264 because the option was designed for the "MPEG" quantizer scale which is not used by x264. Also, this option may have been ignored completely by libx264 at some time, but I can't recall exact details.


Can you give a tip how to create a video with such effect? I really like these effects and I would like to reproduce it.

I would like to point that I don't know how this effect is called. Whether it is made within a camera or in post production?

Here is 2 videos that have this. They are not identical but I think they are quite similar. I like how the video has some kind of distortion.

In the first video it is like fast forward with a lot of camera movement. You can see it starting from here

In the second video it is like fast forward but is slow motion. The effect can be seen when the drummer is in a frame.

So my questions are:

If it is in camera effect how is it made?
How to achieve it in video editing software?

The first one is a so called hyperlapse. Just not a smooth one. It is basically just speed up.

Same goes for the second one, just that it also has a diffrent shutter speed.

So how to do them:

Simply record the walking video and speed it up in post.

To achieve the special look in the second one, not every camera can do that. You need a camera with a really low FPS, for example 10, then you also expose 1/10 second. You should get a similair look, then you will need to experiment. But that effect may be hard to achieve on a digital/cheaper camera.


Is it possible to charge a panasonic HDC SD900 while filming? On this camera, the battery can only be charged inside the camera. So I cannot charge one battery while using an other.
My only alternative is to charge while I film. Can I do that?

Yes, you can.

I first asked the question on a youtube video reviewing the camera. And I got the folowing response:

  Yes, it works. You can do anything while charging.

Now, I have bought the camera and tried it myself, and I confirm that Yes, is it possible to charge a panasonic HDC SD900 while filming.


50% higher bit rate vs 20% higher resolution I have two videos: first one has 50% higher bit rate, second one has 20% higher resolution and slightly higher FPS. Which one will look better? I use a 1080p 72 inch 60 Hz screen at 10 feet distance.

Video 1

Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4
Format settings, CABAC : Yes
Format settings, RefFrames : 13 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 1 h 18 min
Bit rate : 2 966 kb/s
Width : 1 056 pixels
Height : 594 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.197
Stream size : 1.63 GiB (71%)
Language : English
Default : Yes
Forced : Yes
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Video 2

Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, RefFrames : 5 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 1 h 15 min
Bit rate : 2 073 kb/s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.090
Stream size : 1.09 GiB (78%)
Language : English
Default : Yes
Forced : No
Color range : Limited
Matrix coefficients : BT.709

Could you give files (or png screenshots) to comparing?
I think that file with higher bitrate and higher resolution should look better, with other conditions being equal.

1056*594 = 627 264 pixels.
1280*720 = 921 600 pixels (47% more pixels relative to 1056x594 resolution)
921 600 / 627 264 = 1.469 * 100% = 147% relative to 1056x594 resolution.

2966 kbps for 1056x594 - 43% more bitrate for this video, relative to 1280x720
2073 kbps for 1280x720
2966 / 2073 = 1.43 * 100% = 143% relative to bitrate of 1280x720 video.

What do you think?
I think that with these settings both videos should be approx equals. Maybe the subjectivity of the perception of the human view will make its adjustments in this comparing.


FFMPEG how to add image and soundwaves to video I have an mp3 song that I am making a video for, I also have a background image.

My command that doesn't work.

ffmpeg -i song.mp3 -i image.jpg -filter_complex \  "[0:a]showwaves=s=3840x200:mode=line[sw];" \
-map "[out]" -map 0:a video.mp4

I'm trying to read the documentation and understand how to just put the image as a background, overlay the Soundwaves on the Image and keep the audio. Can someone help me understand how to do this?

Use the overlay filter to put the showwaves on top of image.jpg:

ffmpeg -i song.mp3 -i image.jpg -filter_complex "[0:a]showwaves=s=3840x200:mode=line:colors=red|yellow[sw];[1][sw]overlay=(W-w)/2:(H-h)/2:format=auto,format=yuv420p[v]" -map "[v]" -map 0:a -movflags +faststart video.mp4

Adjust showwaves colors with the colors option. Each channel will have its own color, so in this example, if song.mp3 is stereo, the left channel is red and the right channel is yellow.
If you just want a single waveform of all channels add the aformat filter before showwaves, as in aformat=channel_layouts=mono,showwaves=s=3840x200:mode=line:colors=00ff00.


Scrolling Text Looks Bad I want to have a text scroll through a video. I use Kdenlive for editing and rendering and it supports having a scrolling text and simply made it black text on a white background.

It scrolls very fast, way faster than would be readable. Which is intended. However, it should still look crisp (appearing clear, sharp, etc.).

When I stop at any point in the video, the text is as sharp as it could be. However, when playing the video, the text looks blurry.

It doesn't appear to be a player issue. I tried 3 different players, same thing. When I take a screenshot while playing the video, the text looks sharp, too.

I use a 60 fps LCD laptop monitor with 4 K resolution scaled to 1920 px x 1080 px by the operating system and tried 30 fps and 60 fps video.

The problem vanishes when I stand 4 m or more back.

Is this a known problem and is there a solution? Like using colors which aren't as different as black and white for the text and the background or actually lowering the frame rate or showing smaller/bigger text or anything?

Some general advice on motion graphics / rolling text, i dont know KDEnlive so i dont know how to achieve that in your specific software.

Make scrolling speed fit your framerate. If your framerate is 25fps, the text should scroll at 25 / 50 / 75 / 100 / 125 etc. pixels per frame.
If you are using a progressive scan playback device like a projector or a computer screen, make sure your project is set to be in progressive and not interlaced. If necessary, de-interlace video that was shot interlaced before using it in the project.
Never use fonts or graphics that have lines which are only 1px, if you need to do that, duplicate the layer and put a copy of the graphics with a very soft gaussian blur (1 or 2px blur) in the background.
Put a soft shadow around the font, also very subtle, 1 or 2px dissolved shadow.


After Effects P/B-frames aka motion vectors for Datamosh replication I am trying to replicate Datamoshing with After Effects. I'm close but I need to link the displacement map to motion vectors rather than just colors and brightness values. I know AE recognizes motion vectors as it uses them for motion blur. If there is a way to extract and move P/B-frames and apply them to other I frames that would be perfect but I haven't found that yet.

I figure if i could translate motion vectors into shades of black and white i could apply the displacement map to that layer using luminosity. Is there any way to do that? Perhaps extracting motion blur as a separate layer with an alpha channel?

The easiest way to get this kind of effect is to use Glitch - a plugin from aescripts.  It's not going to let you properly combine two sources, but it will go a long way towards giving you "broken" looking digital video...


What are the placards in this picture? I've always wondered what these things are such an awkward angle. I only see them in Whitehouse shots.

They are for the teleprompter.  The words are on a screen below, the angle is to reflect to the speaker's line of site...

I'm sure there are different implementations, but that's the basic gist.


Color Correction filter to dull/desaturate Video Novice w/ After Effects, but here it goes...I am looking to emulate the style/technique from this website background video https://y.co/

Is there a color correction effect to create this look? Or is it something like a solid color layer blended in a specific way?

I have footage I am going to use as the landing page background on my website, and I want to create this effect so the text feels like it is in the "foreground" and stands out on top of the background video.

If you do a primary color correction on your video to get it normalized (this is assuming your footage looks correct in terms of exposure, white balance, etc); I'd add the following filters to achieve that look without any plugins...

You would have to play with the parameters; I haven't seen your footage, so I can't say how strong a filter would need to be applied.

Either ADD and Adjustment Layer on Top of your Footage Layers; or you can nest your comp into another comp and do your color correction there.

FILTERS

USE THIS ORDER ON YOUR FOOTAGE/ADJUSTMENT LAYER GOING TOP TO BOTTOM

Color Correction - Brightness Contrast:   Reduce Contrast (you will have to play with this as I don't know if your footage is High Key to begin with).  But to get that look, you want low contrast footage behind your text, so that you lift your blacks and shadows up. I wouldn't increase Brightness unless you shot 4:4:4.  But you want very low contrast which basically flattens out the overall image and mutes the colors as well.
Color Correction - Hue Saturation Lightness (HSL):   Reduce Saturation by 50%. Increase Lightness: 2-10%  Leave Hue at 0.
Color Correction - Vibrance:  Now that you've reduced your Saturation; adjust the Vibrance Up till you get the colors to punch through to your liking. You may need to reduce Saturation in previous filter or not reduce it so much as 50, depending on your footage. But pulling back your saturation a decent amount, and replacing it with Vibrance will give you the tonality you're looking for color space wise.
Last Filter: Add Video Limiter Filter, and soft knee your Luminance to 99.90.

Lastly; if you want to knock your TYPE out from your footage background, you can add even a very small amount of Blur. Gaussian Blur; or Fast Blur, Lens Blur is nice but adds render time. All options would work for this.

FOR YOUR TEXT

Adding a even small stroke will help it pop. Use video/film friendly fonts, no fine lines/hairline fonts. Some of my favorite fonts for video are:  Gotham Ultra; Gotham Book, Gotham Medium, Whitney (SemiBold, Book, Book SmallCaps) Operator in Small Caps various weights, and if you want Serif, Mercury is a great font, as is Perpetua with the right weight.

If you are using fine line fonts, such as Gotham ExtraLight, adding a stroke of 1px as the same color of your font, and reducing the opacity of the stroke to 50% will help.

And lastly; adding a drop shadow (very subtle so almost not noticable) with 0 Distance, 0 Spread and Size 10-25 (Depending on Fontsize) and then reducing the opacity of the shadow to 10-40% works well.  I particularly don't like the drop-shadow look; but I do use it to get the text to pop out from my motion backgrounds.

Regardless, you want your text to background footage to have a wide latitude of contrast. So if your footage is bright, you'll either want to darken the footage down, or use a solid color layer on it, something to create a wider spectrum if you plan to use a light colored or white font. That-- or use a dark font.

If your footage is dark, either brighten it up, or use a bright colored font. Same goes for color.

FINAL TIP

I would recommend having your project comp set to 32 Bit Floating Point as far as workspace, even if your footage is 4:2:0.  You'll get better CC results.

Hope this helps.

Martin


How to use ffmpeg drawtext without changing the width of a video Folks, I am trying to add text to an mp4 file.  Seems easy enough right?  But once the new mp4 file is generated, the new file has half the width of the original file and is higher.  It is almost like it switches the mp4 file from landscape to portrait?  Here is the command I am using:

ffmpeg -i file01.mp4 -vf drawtext="text='Text Here': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: boxborderw=5: x=(w-text_w)/2: y=(h-text_h)/2: enable='between(t,20,30)'" -codec:a copy file01Text01.mp4

I then attempted to stop drawtext from distorting the video stream but this results in an error:

ffmpeg -i file01.mp4 -vf drawtext="text='Text Here': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: boxborderw=5: x=(w-text_w)/2: y=(h-text_h)/2: enable='between(t,20,30)'" -c copy file01Text01.mp4

Any help on seeing how I can modify the command so that the video width/height is not changed would be appreciated.  Thank you.

Gyan solved it: (see comment above)

drawtext cannot alter the video frame size. Your video is most likely portrait but stored as landscape with a rotation tag, and ffmpeg auto-rotates the video for you. Add -noautorotate before -i to avoid that.


Simple Squib (gun wound) I was wondering if there was a simple way to make a squib to imitate gun wounds without having explosives in an actors shirt.

Two simple solutions:

1.) Plastic bag of blood with a fine wire/string stuck to it.  Thread the wire through the wound hole in the shirt/leg/buttocks of the clothes, and yank.

2.) Lightly compressed air with a blood hose.  Indy Mogul's first Backyard FX episode has a great video on building this kind of rig: http://www.indymogul.com/backyardfx/episode/BFX_20070611


Voice is dropped in ads on cable channel via OTT I am not a video expert. I used to be an audio engineer (like a 1000 years ago) and have done some video editing on my own professional grade editor for giggles but not in the last 10 years.

And yet, I am seeing something that makes me curious. So I thought I would finally ask.

I get cable over OTT via a Roku. Periodically, on channels that have minor packet loss, I have noticed that ads will lose any actor voice and the voice over portion of the content. The background and other sounds are there. Just the voices are missing. For example, an ad for a popular insurance company will have all the background sounds, however, the voice of the person in the video and the voice over announcer are gone. This does not happen for shows. It also does this for most any ad periodically and inconsistently. The same insurance ad can show again in the next ad block just fine. One ad can be missing voices, the next ad is fine, then the third ad is missing the voice. This can happen on any channel from time to time and seems to be tied to very minor packet loss. Basically, the channel is working just fine, just very minor periodic packet loss. This may be a hint.

Strange huh? Any ideas? It is not really a problem for me, just a curiosity. In fact, it is kind of nice so I am not really complaining.

I don't have a definitive answer, but what you're describing sounds like phase inversion on one of the stereo channels. This causes cancellation when heard in mono of anything centered in the mix, as an announcer voice would most likely be. Someone listening in stereo would not hear much if any difference, so I assume you're listening to a mono feed. It's hard to imagine a scenario where a commercial is delivered in a way that would separate the main channels but leave the background sound.

Why only sometimes? Speculating again, there may be one misconfigured server in a group of servers, and playout of any given spot is randomly coming from that server. It's also likely that these are local insertions, since an issue like this would probably be detected quickly at a national level.


How does HDR movie work? The new DSLR camera released by Canon, 760D, has capability of recording HDR movie. My question is how does this work? In still photography, when setting the camera to HDR, the camera will take 3 shots (the mirror will flip 3 times), with different shutter speed to adjust the exposure and then process it to combine into 1 picture.

For movie, definitely the mirror will need to be flipped all the time while simultaneously need to record at different exposure level. So how does the camera manage to handle this?

At a guess, it will be a similar technology to HDRx from RED or Magic Lantern - 2 frames instead of one recorded for every single video frame.

Reference 1: http://www.red.com/learn/red-101/hdrx-high-dynamic-range-video
Reference 2: http://cgi.tutsplus.com/tutorials/a-simple-way-to-shoot-hdr-video-footage-using-magic-lantern--ae-20993

In Magic Lantern every frame is recorded at 2 ISO values, in the case of the RED camera, two frames are captured instead of one with different shutter speeds with the second frame "2-6 stops faster".
The selection of ISO/"stops faster" is carried out by the user in both case prior to recording.

All that has to be done then, is to blend the resulting "dual frames" into a single video frame for an HDR video.
Also, keep in mind that you do not need 3 frames for an HDR - you just want to cover a greater range than a single exposure can cover, this can be 2 frames or 200 frames. For video it is 2.


FFmpeg pad filter calculating wrong width I'm using
ffmpeg.exe -i in.jpg -filter_complex "[0:v]pad=iw:ih+10:0:0" out.jpg

to add a padding of 10px at the bottom of images and videos.
In most cases it works as expected but with some the width is off by 1px resulting in failure with error:
[Parsed_pad_0 @ 000002ba70617c40] Input area 0:0:623:640 not within the padded area 0:0:622:650 or zero-sized
[Parsed_pad_0 @ 000002ba70617c40] Failed to configure input pad on Parsed_pad_0
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0

you can see that the width of the input area is 623 and the padded area width is 622 but this should not be the case since we are using iw to set the width of the padding.
Here is a sample image that fails.

it turns out you can not pad subsampled pixel formats at odd boundries.
the workaroud is to make the boundary even by using
ffmpeg.exe -i in.jpg -filter_complex "[0:v]pad=ceil(iw/2)*2:ceil((ih+10)/2)*2:0:0" out.jpg


What does an external video recorder like a Ninja offer? According to the Ninja Website

  Take your consumer camera to a truly Pro recording device. Avoid the internal MPEG compression & go from sub 30Mbps MPEG to 220Mbps ready to edit 10-bit 422 Apple ProRes HQ.

This External Recording article from Nikon states

  Another useful optional accessory that is often used on more professional video productions is the external recorder. With an external recorder such as an Atomos Ninja attached to a Nikon HD-SLR, you can record a higher quality, uncompressed video signal from the camera directly to the external recorder via HDMI.

I'd like to understand what this means in layman terms? Will the image be sharper frame by frame? Is it like watching a higher FPS? Just more data to pull from when Grading? Is it useful on all video cameras or only high end ones?

If the final video is ultimately going to be uploaded to YouTube would it make a difference?

If you record (typical AVCHD) sub-30 Mbps 4:2:0 video to a card and 220Mbps 4:2:2 video to an external recording device, you will be hard pressed to tell the difference when you view it back on YouTube.  Very, very hard pressed to tell the difference.

However, if you plan to edit the video--changing contrast curves, color, saturation, etc., and especially if you are trying to key any region (whether for green screen replacement or because you want to muck with certain color ranges in certain ways), or if you want to digitally zoom in a bit, then you are going to immediately notice a large difference in how the video behaves in your editing program.

What makes the low bit-rate recording work so well is that the compression algorithms are very smart about fooling our vision system, which is very easy to do.  But such smarts break down almost immediately as soon as you start treating the video as a series of images to be manipulated (which is how video editing programs ultimately "see" the video).  That's when you are going to wish you had recorded in a format that is more true to the digital workflow and less clever about how easy it is to fool our vision system.

If all you ever want to do are the simplest of cuts and fades, you can do that with low bit-rate video.  But if you want to push the image around more robustly, you will quickly realize the need for a higher bitrate solution, which is what the external recorders give you.


KdenLive: Nothing is being rendered on Windows? Let's start off from the beginning: I have already configured KdenLive to point to the melt.exe file, and all the other proper plugins to allow rendering.

When I hit "Render" and try to render to a file, I am told that it has started to render, and then I am instantly told that the render completed successfully, in 00:00:00. However, there's nothing saved to disk.

I tried analyzing the script that generates when you select "Generate Script". It seems to be giving a "usage" dialog due to incorrect parameters. I'm wondering if maybe this is the problem. It reads as follows:

C:\Users\b4ux1\Documents\Vlogs\2017-10-22>"E:/Kdenlive-
17.08.1/kdenlive_render.exe" "in=0 out=100 "E:/Kdenlive-
17.08.1/share/mlt/melt.exe" atsc_1080p_60 avformat -
"file:///C:/Users/b4ux1/Documents/Vlogs/2017-10-22/2017-10-22_001.bat.mlt"
"file:///C:/Users/b4ux1/Documents/Vlogs/2017-10-22/2017-10-22.webm" f=webm
vcodec=libvpx acodec=vorbis crf=15 vb=0 quality=good aq=7 max-intra-
rate=1000 cpu-used=4 threads=4 real_time=-1"
Kdenlive video renderer for MLT.
Usage: kdenlive_render [-erase] [-kuiserver] [-locale:LOCALE] [in=pos]
[out=pos] [render] [profile] [rendermodule] [player] [src] [dest] [[arg1]
[arg2] ...]
  -erase: if that parameter is present, src file will be erased at the end
  -kuiserver: if that parameter is present, use KDE job tracker
  -locale:LOCALE : set a locale for rendering. For example, -locale:fr_FR.UTF-8 will use a french locale (comma as numeric separator)
  in=pos: start rendering at frame pos
  out=pos: end rendering at frame pos
  render: path to MLT melt renderer
  profile: the MLT video profile
  rendermodule: the MLT consumer used for rendering, usually it is avformat
  player: path to video player to play when rendering is over, use '-' to disable playing
  src: source file (usually MLT XML)
  dest: destination file
  args: space separated libavformat arguments

I was having the same problem. Found this fix from the bug reports.  I did it all, exactly as it says, including the part that changes the melt directory in the program as opposed to moving the melt file to match the directory, and it worked. I did not lose my saved project that previously wouldn't render. It's saved in a different location and keeping it did not effect the fix.

https://bugsfiles.kde.org/attachment.cgi?id=108162


MKVToolNix equivalent for .MP4's Good day! I'm looking for MKVToolNix equivalent software for .MP4's. I will use it in a video file without subtitles, I'll find it's subtitle and merge it with the video file just like what I did in MKVToolNix. Thanks!

I just went through a very similar use-case working with TS files.  MoritzLost has the key point but as ffmpeg options can be quite difficult to sort out when you are first getting started, here is a more detailed answer.
Short Answer
For a single input mp4 file and single input SRT file, we can keep all streams from both files and merge them into a new mp4 container (only transcoding the subtitle stream...ie lossless on the audio/video) like this:
ffmpeg
    -i input.mp4 \
    -i subtitle.srt \
    -map 0 \
    -map 1 \
    -codec copy \
    -scodec mov_text \
    output.mp4

If you have unknown stream types, multiple subtitle streams, or other things going on then this may not work and you might need to revise the options.
MP4 vs MKV container - limitations of mp4
You should know that the MP4 container does not support embedded srt (subrip) streams.  It only supports mov_text for soft-subs.  So we have to transcode the SRT to mov_text or use hard-coded subs (where the subtitle text is encoded into the video stream directly and cannot be turned off).
This is one of the reasons that I prefer the mkv container format over mp4.  It allows me to easily maintain multiple audio and subtitle streams with many different formats all within a single file (keep everything together).  Yes overall file size is larger for people that don't care about those extra audio/subs... but I don't share over the network and hard-disk space is cheap.
Plex and VLC and most other modern media players have no trouble with MKV right out of the box...so something to think about whether you really want to use mp4 if you are someone that cares about soft-subtitles and keeping everything together (single file).
ffmpeg
ffmpeg is a very powerful free/opensource tool.  The command line options can be confusing but once you understand how to use the -map and -codec options, you can already do a lot.  If you are semi-technical and do lots of video work it is worth learning how to use the command line on your OS and how to use tools like this.  Windows Services for Linux makes this easier than ever for windows users on Windows 10.  For Mac/Linux it has always been easy to install and run these tools.
How to mux multiple inputs into a single mp4 container
The following would take an input mp4 (or other) file and a second srt input file, take all streams from both files and mux them into a new output.mp4 file.  We tell ffmpeg to copy the audio/video streams (no transcoding or quality loss) and to convert any subtitle streams into mov_text since that is the only type that mp4 container supports.
ffmpeg
    -i input.mp4 \
    -i subtitle.srt \
    -map 0 \
    -map 1 \
    -codec copy \
    -scodec mov_text \
    output.mp4

Depending on how you run this on windows, the \ to continue the command on the next line may not work and you may need to remove the backslashes and condense the command into one without newlines.
Again but with comments explaining the options.
ffmpeg \
    -i input.mp4 \          # first input file (index 0)
    -i subtitle.srt \       # second input file (index 1)
    -map 0 \                # select all streams from first input file
    -map 1 \                # select all streams from second input file
    -codec copy \           # copy audio/video streams (no transcode)
    -scodec mov_text \      # transcode all subtitle streams to type mov_text
    output.mp4              # name of output file

Running this command will show you output something like the following for a simple input mp4 with a single audio and video stream.
...
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
  Stream #1:0 -> #0:2 (subrip (srt) -> mov_text (native))
...

You can see it copies the first two streams (audio/video) from input 0 (the first input) and does a conversion on the third stream from input 1 (the second input...the srt file).
Alternatively, go from MP4+SRT to MKV with mkvtoolnix
If you aren't opposed to MKV containers, then there is no reason you can't just take the input mp4 and separate subtitle file and mux all the streams into a new MKV file instead.  This would also keep the SRT as an SRT and not transcode it into mov_text.
Remember MP4 and MKV are just "containers" and so you can copy around the video/audio/subtitle streams from inside these containers without any transcoding (loss of data/quality)...as long as the destination container type supports that stream's codec.
mkvmerge \
    --output output.mkv \
    input.mp4 \
    subtitle.srt

In this case, because we are taking all streams from the input files and mkvmerge doesn't do any transcoding, the command is much simpler.
If it was me with your use-case I would just go to mkv unless you are trying to build a file for a player that only supports mp4 and don't have any other option (ie get a different player).
References
https://en.wikibooks.org/wiki/FFMPEG_An_Intermediate_Guide/subtitle_options#Set_Subtitle_Codec


4k upscaled Blu-Ray vs 4k upscaling on a TV I was recently looking to purchase Game Of Thrones Season 1 on 4k Blu-Ray however after doing some research it seems that the first season was actually all shot in 1080p so the 4k blu ray discs are is just upscaled versions of the original content.

I was wondering if letting a TV upscale 1080p content to 4K would be any lesser quality than buying the 4k Blu-Ray discs of the upscaled 1080p content.

It really depends on the methods of upscaling in both cases, but your TV upscales "on the fly" for each moment, which is meant to be fast while compromising on quality. One would imagine a studio releasing a 4k version took their time processing and rendering that 4k upscale to their liking and only then release it.


How to do <=1 Hz timelapse photography with Canon 7D? I'd like to take 1 Hz and sub-second timelapse videos with my Canon 7D. I've tried both DslrDashboard and Magic Lantern, and couldn't figure out how to set the timelapse any faster than that. Worse, both of them ended up taking photos at such a jittery rate that I could hear it was completely off kilter. The camera would take one photo, then wait for a couple seconds before taking two in less than half a second, and so on, making the result unusable for video making. I was using manual mode, and shutter time, f-stop and ISO were all set to static values.

The camera is otherwise perfectly capable of taking many photos per second, even at RAW quality. Is there some fundamental issue with the timing used when remote controlling (and even when using custom firmware) causing this, or did I miss an important setting to make it all work? If this is simply an issue with both these products, are there other software products (preferably FOSS) which will reliably take 1 Hz or faster time lapse series?

(Repost from photo.SE after suggestion.)

The problem isn't the remote timing, it's the rate at which data can be written to the SD or CF card.  The camera can shoot a bunch of images quickly in burst mode because it stores them in an internal buffer for a short while before it writes them to memory.  However, this pace of data acquisition is not sustainable for long periods of time because the buffer will fill up before it can offload to the card.  The best thing you can do is make sure you're using cards with the fastest write speed possible.  Shooting jpeg only might also help, depending on how quickly the camera converts RAW to jpeg.


Any way to change properties of subcomp based on parent comp? I have a dozen 'main' comps which have a bunch of nested comps. I need to create about 30 versions of each main comp, with different colors.
The subcomps are animated shapes, which take their color from a color picker in the main comp.
I would love to avoid having to duplicate all the subcomps 30 times, so I don't have hundreds of copies.

Is there ANY way to allow a nested comp to change based on the comp within which it is nested?

I know there is no "thisComp.parent" option -- since a comp can be nested in many different parents -- but is there a way to "push" a property "down" into a subcomp? Or any clever workaround? Does this make sense?

E.g., main comp "M01" has subcomps "S01a", "S01b", etc. The colors of shapes in S01a etc are based on a color picker in M01.
I want to duplicate M01 to M02, change the color picker value, and have S01a S01b pick up the new color value, without having to duplicate them to S02a, S02b, etc in order to reference M02.

I'm using True Comp Duplicator, which is a lifesave with its 'update expressions' option ... but my project is over 50MB now, with hundreds of comps, and is unwieldly.

(I cannot use a 'change color' effect in the main comp; there are transparencies & blend modes that would get messed up.)

You can link properties in different compositions by using an expression like this one.

comp("Comp Name").layer("Layer Name")("Property e.g. Transform")("SubProperty e.g. Position")

If the property is more nested you just add another ("sub property") until you reach the property you need, just as you would click through the drop down menus.

Also helpful: VideoCopilot recently released a great free script specializing in pre-comping 3D layers in exactly that way. http://www.videocopilot.net/blog/2014/08/free-script-3d-pre-compose-tutorial/

Edit: Regarding the clarification in the comments about using relative selectors for comps.
Unfortunately not possible per se. You can do it with layers by specifying the index number but a comp doesn't really have a unique parent which makes this rather hard to have a generic selector for comps. If you have a unique procedural naming based on your comp "depth" this might be possible with some advanced expression or maybe script but if you just named them "my cool comp" and "my other cool" comp you can't really make a script for that.


Corrupt video when playing through JW Player I have some files that when played in jwplayer the playback is corrupt.
The files are encoded to h.264 using FFMpeg and there is other files encoded in the same way that works.

At the moment we only use the flash version of the player.

The corrupt playback looks like this:

http://adam.ingmansson.com/public/jwplayer-corrupt-video.png

This problem started showing up after we did an upgrade to FFMpeg, so I haven't ruled out that it could be an encoding error.

the command used to run FFMpeg is:

ffmpeg
    -i /home/ftp/1c8f08b7d0d9e7fa4b24066156ad50bc981497a0.mov
    -vcodec libx264
    -preset ultrafast
    -profile baseline
    -acodec libfaac
    -ab 96k
    -crf 19
    -vf movie="/home/adam/logo.png [watermark]; [in][watermark] overlay=main_w-overlay_w-10:main_h-overlay_h-10 [out]"
    -y /home/ftp/1c8f08b7d0d9e7fa4b24066156ad50bc981497a0.flv

I am in no way an expert in FFMpeg commandline, so feel free to point out any mistakes made.

FFMpeg info:

ffmpeg version git-2012-05-02-2330eb1 Copyright (c) 2000-2012 the FFmpeg developers
  built on May  3 2012 08:51:25 with gcc 4.4.3
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-version3 --enable-x11grab
  libavutil      51. 49.100 / 51. 49.100
  libavcodec     54. 17.101 / 54. 17.101
  libavformat    54.  3.100 / 54.  3.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 72.103 /  2. 72.103
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 11.100 /  0. 11.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/ftp/javarecorder/aeb1038bd3e380782e2293cfdeb56ba8fab0d167.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2012-05-15 16:33:35
  Duration: 00:25:01.00, start: 0.000000, bitrate: 4299 kb/s
    Stream #0:0(eng): Video: qtrle (rle  / 0x20656C72), rgb24, 1920x1080, 3593 kb/s, 9.24 fps, 1k tbr, 1k tbn, 1k tbc
    Metadata:
      creation_time   : 2012-05-15 16:33:35
      handler_name    : Apple Alias Data Handler
    Stream #0:1(eng): Audio: pcm_s16be (twos / 0x736F7774), 44100 Hz, 1 channels, s16, 705 kb/s
    Metadata:
      creation_time   : 2012-05-15 16:33:35
      handler_name    : Apple Alias Data Handler

Seems like the framerate was the problem. JW Player seems to have problems playing videos with high framerates (like 1k).

A simple -r 30 in the FFMpeg command seems to have solved it


What is the terminology for AR text in a video? I'd like to learn how to add text in a video that's anchored to a 3d space in a video like augmented reality, but I'm having trouble finding out what this kind of effect is called.

Example:

In the example the text is also 3d, but I'm mostly interested in the AR style text effect itself, I plan to add 2d text to a video, basically moving credits that move like an AR object.

Thanks,

There's not much to it, the effect could be called "3D tracking Text" or something like that.

Open up After Effects. Load up your file that you want to put the text in. Use the camera tracker that natively comes in After Effects. Now, you can attach a null to one or more points that are automatically generated and detected, which will follow the geometry and movements from the footage. Once you're happy with where the null is positioned, you can create a new text layer and parent it to the null, so that the text is following its position, rotation and scale. That's it.

Creating a 3D-Text however is a different story. For that, you could use the element3d plugin for aftereffects, but that's quite expensive. Alternatively, you could track the camera and export the tracking data to a 3D-environment. I'd recommend using pfTrack for the tracking part. Then, inside the 3D-Program (like Cinema4D, Modo, 3Dsmax, Maya, etc.) you can import the tracking data which will give you a camera that matched the movements of your footage. If you then just place an object, like 3D-Text in the 3D-Space and render the footage from the perspective of the aforementioned camera, you can place that footage on top of your original footage and the object will stick.


Dump keyframes of a livestream I'm trying to create a "highlights" gallery for an event that's been livestreamed (say an Apple product launch keynote or similar H264 stream) - is there a way using FFMPEG to dump all the keyframes / a frame every 5 seconds into a folder as images? I can then curate the most interesting ones.

I'd think that keyframes are a better bet because they'd represent a scene or camera angle change, which would correspond to "interestingness", but are there any other better ways to do this?

Basic form is

ffmpeg -i livestream -vf select=key -vsync 0 -q:v 1 snaps%d.jpg


after effects letters animation Hi guys I am pretty new in after effects.  Please guide me to create something like this.

Effects's names etc.

To do that I'd use animated masks on each letter to reveal them. First I'd make the text layer, then one by one add masks.  So for the M I'd:

make a small rectangular mask just below the bottom of the lower left leg, the same width as the leg.
Because we want to see the letter while we're animating the mask I'd set the mask mode to none temporarily.
Turn on animation for the mask shape (hit m to reveal the mask shape property and click the stopwatch to turn on animation, or just hit alt / optshiftm)
Next I'd move the playhead a couple of frames to the right and drag the top two vertices of the mask up so that they follow the shape of the leg. If the mask was set to add at this point you'd see a bit of the M's leg appearing. Align the top right vertex of the mask with the inside vertex of the leg, where it meets the downward stroke.
move say, another frame right and drag the top left vertex of the mask so that it is aligned with the top left vertex of the M. A bit outside it is probably best.
move another frame along and now add another vertex near the top left one. Move it to the top-right side of the first leg of the M
move this new keyframe and the old top-right keyframe to reveal the first downward stroke

…and so on. Basically you just reveal the character with a mask. Remember that between keyframes mask vertices always move in straight lines. So to get them to move in a curve you need to add lots of intermediate keyframes. You can also use smart mask interpolation to help.

In the video above it happens twice, so you can just copy the layer, set the opacity to 50% and start it a few frames earlier.


How can I convert a 3D SBS video to individual left side video and right side video? Let’s suppose I have a 3D SBS video and I want to convert it such that I get two video files, one for left side video and one for the right. How can I do it? Is it possible to do so programmatically?

You can use FFmpeg, a free commandline tool to do this.

ffmpeg -i sbs.mkv -filter_complex "split[l][r];[l]stereo3d=sbsl:ml[left];[r]stereo3d=sbsl:mr[right]" -map [left] -map 0:a -c:a copy left.mkv -map [right] -map 0:a -c:a copy right.mkv


Faster deinterlacing with ffmpeg and yadif We are using two-step encoding with ffmpeg to encode raw .mov files to multiple .mp4 encodings ready for streaming over the Internet. Some of the videos are interlaced and we are using yadif to deinterlace them with the following options: yadif=1:-1:0.

Without yadif, regular 2 hour videos take about 3 hours to encode into 6 different .mp4 files (different resolution and bitrates mostly). When adding yadif, encoding takes 6-10 hours.

Our knowledge with videos is limited, so we are wondering can we make the deinterlacing faster? What if first deinterlace the source .mov file into new .mov file and use that as a source for mp4s, will that be faster?

Thanks.

Yes, you have the right idea.  If stib's suggestion of making multiple outputs in parallel with the same ffmpeg commandline doesn't quite do the trick, then use a temp file to hold a lossless copy of the output of any slow filtering:

ffmpeg -i src.mkv -vf yadif=3:1,mcdeint=2:1 -c:a copy -c:v libx264 -preset ultrafast -qp 0 deinterlaced.mkv

(never use ultrafast except with lossless, it's WAY worse than superfast -x264-params cabac=0, and not much faster.)  CABAC takes most of the CPU time at lossless bitrates, but it does save 15% bitrate vs. CAVLC.  If you have a ton of scratch space to work with, you could use an uncompressed output file.  Lossless x264 is about as fast to decode as ffvhuff, if not faster, but half the file size.  I think it's your best bet for scratch files (pretty good CPU usage, ASM-optimized decoders, and one of the best as far as compression ratio).  Simpler codecs like ffvhuff might have a place if you need to frame-step backwards without taking seconds per frame, or you could just lower keyint in x264.

Then do whatever you normally do, but with deinterlaced.mkv as your source.

I think I remember reading about someone having added support to x264 for making multiple encodes at different bitrates at the same time.  So motion-search, frame-type decision, and a bunch of other analysis only has to be done once.  I'm not sure if that was just for google's internal use, and it never got merged, or what.  Neither the vanilla x264 cli frontend, nor the ffmpeg libx264 wrapper, have options to activate a feature like this.  I'm pretty sure I would have noticed that in x264 --fullhelp output at some point.

If you have to do a lot of encoding, it'd be worth searching around to see if there's any way to get your hands on a publicly available implementation of this.

This is different from having ffmpeg feed the decoded/filtered video to multiple instances of libx264 in parallel, since each instance would still need to do all the analysis independently.

If you do use stib's suggestion of multiple outputs from the same ffmpeg, reduce x264's number of threads.  By default, each separate output file will auto-detect the number of CPUs in the whole machine, so you'll have 6 times the number of worker threads needed to saturate your CPU cores.  Maybe use 2 or 3 threads for the HD outputs, and single-threaded for the lower-rez outputs, since you want to balance things so all your available CPU time gets used, without having more threads than needed causing extra context-switching overhead.

For HD video with a lot of reference frames, each libx264 instance would take a good chunk of RAM, too.  Reducing thread count doesn't help with this much, since all the threads are reading the same data.

6 instances of libx264 at the same time, instead of multiple threads from the same libx264, will be competing for memory bandwidth / cache space.  They'll each have their own copy of the frames, instead of getting cache hits from each other.  This might or might not be an issue on your hardware.  If this or the RAM-size is an issue, use a temp file and do 3 outputs from one run, and 3 outputs from the next.

yadif (and mcdeint) are not multithreaded.

Or you could deinterlace and output to lossless + some of your desired output rezzes, then generate the rest of your rezzes in another pass of the lossless file.  If you don't have multiple videos queued up to process, this would let you pipeline things to get max use out of all your cores while still not doing all the encodes at once.

If you do have multiple videos to process, you could have a video deinterlacing while you encode another, if you think setting that up is simpler than multiple outputs + lossless from the ffmpeg that runs the deinterlace.  Run the encodes with nice -19 or something, so they don't take CPU away from the ffmpeg process doing the deinterlace.


Noise (from autofocus?) during Video on DSLR I have a Canon 6D Mark II and am shooting video with a Canon EW-83H lens. The videos come out great but are plagued by audible creaking and clicking sounds during playback. My guess is that this noise is due to autofocus of the lens. I tried two other lenses (one prime and one telephoto) but both basically have the same issue. The camera is brand new but the lenses are not (but in good condition).

Is this an issue with my set up in particular or is the always an issue with shooting a video with a DSLR and a lens with autofocus + IS? What's the recommended solution?

The noise you talk about is usually caused by lens motors related to autofocus and motors, related to image stabilization. The best you can do is to use external microphone and connect it to microphone port of the camera. This will give you better isolation of the recorded sound from camera noises and better sound quality.

Of course you can always use external sound recorder and sync video and sound in post.

EDIT: to avoid the noise from focus motors you can use manual focus. To avoid noise from stabilization motors (if any) you can switch off image stabilization (VR, OS, IS or whatever it is named) and use rig with stabilization or tripod.


Best practice recording VHS to digital I have a home video on VHS which I want to transfer to someone else. As I don't have two VHS recorders I am looking into other ways to duplicate the footage.

I am considering two options to do this:

Using a Canon 550D with a
Sigma AF 18-50mm f/2.8-4.5 DC HSM OS lens to film the footage from a full HD 27 inch TV in 1920x1080 at 24 fps.
Using a cheap VCR to USB adapter to capture the footage directly to the hard-disk.

What is the preferable option in terms of quality?

The best option would be either to send it out to someone that has a good capture capability or invest in a decent quality RCA capture card.  The USB option will work the best of your two suggestions, but it is still likely going to be a decent quality loss (granted, VHS in general may not be that high to begin with.)

The first option is not worth considering as the result would be completely substandard.


Colors look different after export Colors look great in FCPX.

After I export (Share > Master file > H.264 Quicktime) they look a bit dull: desaturated, less vibrant. Also sort of like the wrong gamma curve - shadows are darker.

I realise compression is lossy but is this expected?  Should I over-saturate the video in FCPX a bit to compensate?

I saw some very technical forum posts talking about color-space conversions last time I googled for this, suggesting maybe Quicktime uses the wrong 'matrix'.  I am not a video pro but the visual difference does remind me of what can happen with RGB > CMYK and colour profiles in the print world.

At first I thought it was only after upload to YouTube, but the issue is there when I play back the exported .mov too.

Does anyone have any tips or info?

You may need to perform a “trim pass” to export to Rec709 colour space.

See: https://images.apple.com/final-cut-pro/docs/Wide_Color_Gamut.pdf

Matching colors in Rec. 2020 and Rec. 709 masters

When some colors are translated to the narrower gamut of Rec. 709, they may look
different. To ensure that the Rec. 2020 master and Rec. 709 submaster look similar, you can perform a trim pass color adjustment on the Rec. 709 timeline to bring all the colors in line with broadcast specifications. When performing a trim pass in a Rec. 709 timeline, you should attempt to match the look and feel of the Rec. 2020 timeline as closely as possible.

Prepare for the trim pass

In the Final Cut Pro browser, select a master Rec. 2020 project and then choose
Edit > Duplicate Project as Snapshot.
With the duplicated project selected in the browser, choose Window >
Project Properties (or press Command-J), then click the Modify button near
the top-right corner of the inspector.

In the dialog that appears, click the Color Space pop-up menu and choose
Standard - Rec. 709.
In the browser, click the name of the duplicated project (the submaster), then type
“Rec. 709” at the end of the name.
In the browser, click the name of the original project (the master), type “Rec. 2020”
at the end of the name, then press Return.


How to fix Sony Vegas 12.0 blank screen render? I've got video recorded from my phone and I use Vegas to edit them, when I play the video back in VLC player the video orientation is ok, but when I import into Sony Vegas and it asks if I want to set project preferences to match the media, I have

allowed the Vegas to match the project settings and the orientation changes to portrait.

when this happens I change the project settings to make the project settings to landscape and then use track motion to straigten the video. But when I render, its always a blank screen with the audio playing in the back ground.

not allow Vegas to match the project settings and the video shows portrait with the black strips on the side.

I then use track motion to straighten the video but the render produces the same result. Blank screen with audio.

I do not know why this is happening, how would I set up the import and project preferences so that the movie renders properly?

Note: All videos are mp4 format. And the media offline checkbox doesn't make a difference, checked or unchecked.

Use VLC to get the actual frame size. You can go to Tools/media information and from there navigate through the tabs to see what the frame size is.

Then enter that information manually into vegas. When you drop your clips in everything should be good to go.

If you are still getting blank frames in the rendered video then I would guess that to be a render setting. You may want to render to a default setting to see if that helps.


Visual equivalent of VST What would be most similar in concept to VST effects but for visuals?  In other words, is there a standardized interface for running VisFX on a video in the same way that one can run VST realtime effects on audio?

It really depends on how much you care about realtime operation.  VSTs tend to be used both for production and performance, but with video, because there's so much more processing involved, things tend to be split between production and performance.  That being said, for production, After Effects plugins are probably the closest analogy.  For performance, probably Freeframe.

Freeframe is a format that's specifically tailored to be cross-application, but on the production side of things, I don't know of anything that transcends applications the way that VSTs do.  Each video production app tends to have its own format.  The main reason I say AE plugins are the closest analogy to VSTs is because AE itself is almost as ubiquitous in the same application price range/platform.

So there's not really an exact analogy (if you consider all the various factors), but there are similar things out there.


How can 1080p films be so disproportionally lightweight? I calculated that for a film of 2 hours with 30 fps, over a 1920*1080 (16:9) display with 32 bps (True Colour) had to weight : 2×3600×30×1920×1080×4 Bytes which is 1,7915904×10¹² so 1,8 TB...

Is there something I didn't get right? Or is it that uncompressed, I could not have more than 1 film stored on my computer to watch on my very standard 1920*1200 Display?
Are the films that are shot and projected in 1080p really that size?

And my question is : if so how are Blu-Rays compressed into a measly 25-100 GB disk? I thought DVDs and such were lossless encodings and even if not how can we lose 95%+ of the information (100GB/2TB) and be ok watching it?

DVD and Blu-Ray content makes massive use of lossy encoding.

An easy way to see for yourself is to find a dark scene in a film, and then pause it. If the only issue was a limited number of black levels, you would expect to see a stepped gradient curve from the darkest region to the lightest region. Of course, if true 24-bit color was being used, the "stepping" would be too subtle for your eye to see. But the video isn't even that good! You will most likely see large solid rectangles in the black part of the screen. This is the result of the compression algorithm "guessing" that a square is a good enough approximation, and everything within the square is close enough to the same color to just use one color.

This works well most of the time, but tends to fall apart in films that make extensive use of dramatic dark scenes.

Added from comments: Encoders "cheat" on everything they possibly can. If you can think of something new to "cheat" on that most people won't notice, you can make a lot of money licensing your codec in the video production world.


Producing small H.264 files with Adobe Media Encoder vs ffmpeg/libx264 I am a terrible ignoramus in the subject, but the coronavirus has thrown me in the business of producing videos with my lectures. I care a bit for video quality and a bit more for small size. My source is probably seen as abysmal from professionals: it is a screen capture (4K) by Zoom, heavily compressed. It still looks fairly decent and I import clips in Adobe Premiere Pro 2020 and edit them. The problem is in encoding the final sequences.

I lazily started by using the default preset for H.264 ("Match Source - High bitrate). Unsurprisingly, files are very big but visual quality as good as it gets. Good enough for me at first.

Then a student suggested I use this to compress the videos with this

  ffmpeg -i input.mp4 -vf scale=1920:-1 -vcodec libx264 -crf 20 output.mp4

I did not run myself but he sent me an example and my 1.4 GB file went down to 74 MB without any particularly noticeable quality loss (note that most of the videos are slides and completely static for minutes, so it stands to reason that they compress very well). Here an example of typical frames:

Great, but, of course, I thought that I would not reencode with libx264 and rather produce similarly small files directly from Adobe Media Encoder. Firstly, I reduced the resolution to 1920x1080 during the export. Then, I spent an inordinate amount of time with the default H.264 encoder ("Hardware Encoding") to explore what happens reducing the only control I thought I should focus on (Target Bitrate). I would not manage to go below 650 MB with the smallest target bitrate (0.19 Mbps) but could reach 420 MB with a target bitrate of 1 Mbps. This makes little sense to me, but then I read somewhere to use the "Software Encoding" to get small files. I tried (also exploring blindly different profiles: Main, High, High10) and set the target and maximum bitrate also to the minimum (0.19 Mbps again). Size went down to 112 MB and, although not as small as the libx264 file, I thought it would be ok. The problem is that the quality degraded very noticeably. Here are a couple of examples:

Clearly, I must be missing something pretty fundamental here, but what? Is it possible that Adobe Media Encoder is so much inferior to libx264? Did I miss some key encoding parameter? (There do not seem to exist many in AME, nor they look like those of libx264.)

Any help would be much appreciated!

p.

Adobe licenses its H.264 encoder from Mainconcept, which doesn't do that well at low bitrates. x264 is pretty much the frontier when it comes at low size output for a given quality target, or quality for a given bitrate target. x264 is what's used by platforms like Youtube / Vimeo ..etc to encode user videos.

One thing you could try is to increase the keyframe interval. Default for x264 is 250 frames. Mainconcept will be something around 30-60 frames. If you can get them similar, I expect this to provide a moderate benefit in AME's encoding.

It is possible to use x264 with Adobe tools via VFW - https://sourceforge.net/projects/x264vfw/files/. But I don't recommend it. It's not maintained and there were stability issues.

My recommendation is to export a lighly compressed 1080p encode from AME - possibly DNxHD/HR codec in MOV or MXF container format, and then run the following ffmpeg command:

ffmpeg -i input.mov -c:v libx264 -crf 20 -movflags +faststart output.mp4

The faststart flag helps with quick playback start for web viewers.


How can I merge a large collection of video-audio pair of clips without having to repeat the work for each individual pair in primier pro? I have a  large collection of video clips each with its corresponding audio clip that I want to merge. I need to automate the process by having each video clip merge with its  respective audio clip and have all the merged clips exported as mp4 file. How do this in adobe premier pro 2020?

What format are the seperate audio/video files? Are the audio files currently in sync with the video?
I did this recently with some old source files that had originally been authored for DVD, the source files were .m2v / .wav pairs of files. I used TMPEGEnc Smart Renderer to merge all the source files into one big .mpg file (no re-encoding in this step with that tool, so no quality change), and then fed the resulting file into Handbrake to get an MP4 file. For a one-off, you can likely just use the trial version of Smart Renderer.
For Premiere it would basically be the same, import all the source files, create a sequence, and then drag the video & audio files onto the sequence as appropriate, and export to H.264 Format. Smart Renderer worked easier for me, as the files were mostly prefixed with number order, and the video/audio files had matching names, so I could literally just import a folder at a time into the project, and not have to rearrange anything to get the correct pairing and sequencing - a bunch of the manual sequencing work got done for free by doing it this way. Premiere just would have taken longer to do the same job, plus not trusting myself not to make a mistake somewhere manually building the sequences.


Long distance, low light I'm taking a video next month which will be in a dark conference room with a well lit stage. I need to set up a camera to video the presenter, but this year we have many more attendees, more tables, etc — so the camera will be 100 ft away from the podium (last year we got decent results from 40 ft away). It's a JVC GY-HM180U camera.

Any suggestions / recommendations on how to get the best possible image quality?

People need to define the priorities, if the video footage is important to assign a good place to the camera. A television studio with a live audience is a good example of the priority.

Of course, this is not the case, but I am pretty sure these days is not the opposite to that. It has some importance to be streamed, "Youtoubed" or something. So, talk to the organizers and define a good place.

On the case, you really, really can not be closed or in a better spot, Define if the lens is long enough for the case. Define if the camera shake at that distance, moving the camera to follow the presenter is good enough, define if that shake can be compensated filming on 4K and cropping to stabilize.


In fcpx, Can I edit source media in time line and have the changes be reflected in the project? I'm editing a screen cast in fcpx. I imported the media and made a project with lots of cuts send transitions. Now I need to blur some text so it's not visible on the final version. I opened the source media in timeline  and applied my changes, but the project is not showing my changes. How can I update the project?

Once you have placed a clip in a project, it "breaks" the relationship with the original clip. I suppose this is so you don't make a change to a source clip and inadvertently change it in a project where you didn't intend to change it. I'm not sure that it's useful like that, but its the way it is.

There is an exception, multicam clips. If you make a change inside a multicam clip, the change will carry through all of the edits. But that won't help you now.

If your blur is in the same spot for the entire clip, there are a few easy ways to fix it.

Blur your text in one of the clips. Copy the clip. Select all of the rest of the clips. Command+Alt+V to paste attributes, and the blur will be applied to all of the clips at once.
Download Alex4d's Adjustment Layer title effect. Connect the title clip to your project so that it covers every clip that you want to apply the blur to. Now make your blur. This is nice because you can tweak the effect without having to remove the effect from all the clips and reapplying the clip.
The long way. If you were going to use the exact same setup and want to blur out the same text in the same spot across projects, create an effect with just the blur in Motion and publish it to FCPX. Probably not helpful in this particular situation unless you will use this a lot.


Can we produce true 3D holograms yet? Do we currently have true 3d animated holograms yet? Images that we can walk around and see as 3d? I'm pretty sure we have this for still objects but I've seen plenty of videos of animated concert holograms and they are only looking face on at the stage.

It depends what you regard as "true 3d" but there is a technique called "Light Field Display" which has been in development for some time now. Its essentially still a 2D screen but you can walk around and look at it from different angle as if it were an actual 3d object.
http://gl.ict.usc.edu/Research/3DDisplay/


Divide a video into parts I have just edited a 4 hours video down to an hour, and now want to make that 1-hour long video into parts of 12-18 min. How do I do that without the need to render the 1-hour video first?

Also, is there a way that I can take my microphone recording from video and put it into Adobe Audition to remove white noise and background noise?

Most video editors support marks, and importantly "in" and "out" marks.  Generally, if you set your in and out marks for each of the 12-18 minute segments you want and render the sequence, what renders out is not the whole hour, but only the frames within the in and out marks.  If you do that 5 or 4 times, you'll get the segments you want.

There is essentially no way to remove white noise; you can duck it (meaning reduce the volume of the white noise) during times when there are no other interesting audio signals, but when there's a voice you want to hear, that voice is going to blend with the white noise and it will be heard.  Background noise is also very difficult to eliminate, which is why it is always best to pay attention to audio up front.


How to see if a video file is progressive or interlaced? I can check the resolution of a video by Right Clicking -> Properties -> Details -> Video.

Is there a way to see if the video is progressive or interlaced?

You should be able to tell just by looking at it.  When you watch for motion and see a comb-like horizontal pattern, the video is interlaced.  You could also try pausing the video at several points and looking for this pattern, but not every frame will look interlaced.  Pause the video at points where there is quick motion, and step forward one frame at a time.  Make sure the video is displayed at %100 zoom. If you find a frame which exhibits this pattern, the whole movie is interlaced.  Once you know what to look for, you'll recognize it instantly.


How can you fix color banding from VHS video tape in post-processing? Old VHS tapes often have horizontal lines/bands that slowly scroll up or down the video during playback. This video is already on DVD, so I am trying to remove the banding in post-processing.

The Tools I'm using include:
VirtualDub, AviSynth, Premiere Pro CC, Davinci Resolve.

Are there any techniques, plugins or scripts that can help remove this?

Neat Video has been working miracles on footage for us so far, you can give the trial a go! We've never tried it on this specific artifact (that I know of) but it does have features for restoration/archival type damage, and I highly recommend it.


shooting NTSC in Europe On the Sony a7s II in PAL mode I get 100 fps video, but in NTSC I get 120fps.

I am in Europe. If I switch to NTSC and shoot inside, what effect would that have? As far as I can tell, it only plays a role when shooting inside, with artificial lighting, correct ?

The two principal reasons for shooting a region-specific frame rate are (1) reasonable synchronization with environmental electrical and lighting systems (thereby minimizing flicker) and (2) reasonable compatibility with playback devices and their assumed frame rates.

That said, there are reasons people want to shoot "off speed".  It is quite popular these days to shoot at altered frame rates and/or shutter angles for aesthetic purposes.  Such creativity requires a little knowledge about how those changes are going to be affected by environmental electrical and lighting systems, and how those choices are going to play when finishing the footage to be played at the given frame rate of a particular market.

Shooting at 120 fps in an environment lit with lights fed by 50Hz mains is very likely to result in unpleasant light power phase problems.  Shooting at 120 fps in sunlight and slowing the frame rate down to 25Hz will provide 20% more slow-down than shooting at 100fps, which might be desirable for your subject (and not a problem for other reasons stated above).  If you are shooting exterior night scenes lit by sodium, mercury, xenon, and/or neon lights, you are back in trouble again.


Is 0.0036% time inaccuracy on a consumer-grade camcorder expected? I did an experiment on our church's camcorder (Sony Handycam HDR-CX380) recently to test whether it was the source of a time inaccuracy between our video recordings and PC audio recordings of sermons (see Identifying source of audio drift between camcorder and recording PC).

What I discovered is that video files recorded by the camcorder are about 0.0036% shorter than a stopwatch measurement of the same events. (Example: 3:56:52.81 of stopwatch time led to a file with duration 3:56:52.30.) It's not noticeable when watching the footage on its own, but when I try to match a high-quality audio recording to the video, the bad lip-syncing is noticeable.

Is this kind of inaccuracy in recording times typical for consumer-grade camcorders? Or is our camcorder "broken" even by consumer-grade standards?

IME, 0.0036% is rather better than average. Consumer gear operates on quite inexpensive crystal oscillators. These oscillators or crystals are not tuned precisely (or they would cost too much), and they don't have extraordinary stability over temperature ranges.

Professional gear uses special techniques to keep audio and video gear in synchronization.  They use premium-quality sync generators with oscillators that cost more than your whole camera. And even then, they must be re-synchronized several times per day.

And traditional broadcast gear would have a master sync generator, and all the cameras, switcher, etc. would "slave" to that central reference so that everything would be in lock-step.

It sounds like your gear is operating properly. Nothing is "broken". That is simply normal and expected performance.

If you need to sync video to your reference audio track, it is MUCH better to "stretch" or "shrink" the video to fit the audio than vice-versa. Slightly changing the length of the video track with simply insert (or remove) an extra frame every few minutes, which almost nobody will notice.  But slightly changing the length of an audio track is likely to create quite noticable and annoying artifacts.

It is simple enough to try it for yourself. Try slightly changing the length of a long video clip and watch the results.  And then try the same with an audio track. You may be lucky that you can get away with it. Only you can try the experiment with YOUR content and YOUR editing system, and YOUR expectations.


What codec do I need for this video file? I have a video file from my Hikvision NVR which I cannot play on Windows 10 in either VLC or Windows Media Player - all I get is a black video and the seek bar just whizzes along...

I can play this video in VLC on Windows 7 so I'm pretty sure it has something to do with the fact that it is a new computer.

Media Info gives me the following:

Complete name               : C:\Users\cos\Web\PlaybackFiles\2018-07-18\192.168.1.250_02_20180718224704172.mp4
Format                      : MPEG-PS
File size                   : 3.40 MiB
Duration                    : 1 min 51 s
Overall bit rate            : 257 kb/s
FileExtension_Invalid       : mpeg mpg m2p vob pss evo

Video
ID                          : 224 (0xE0)
Format                      : AVC
Format/Info                 : Advanced Video Codec
Format profile              : Main@L5
Format settings             : CABAC / 2 Ref Frames
Format settings, CABAC      : Yes
Format settings, ReFrames   : 2 frames
Duration                    : 1 min 51 s
Width                       : 2 560 pixels
Height                      : 1 440 pixels
Display aspect ratio        : 16:9
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Color range                 : Full
Color primaries             : BT.709
Transfer characteristics    : BT.709
Matrix coefficients         : BT.709

Audio
ID                          : 192 (0xC0)
Format                      : MPEG Audio
Duration                    : 1 min 51 s
Compression mode            : Lossy
Delay relative to video     : -5 min 7 s

Text
ID                          : 189 (0xBD)
Format                      : RLE
Format/Info                 : Run-length encoding
Duration                    : 1 min 41 s

I'm sure this is a codec, or perhaps lack of codec, issue but I need some help to determine what the cause of the issue is.

Has anyone experienced thisbefore?

There is hardly any video in your AVC file. The data rate is 0.2Mb and the frame is a full size PC desktop resolution (WQHD) instead of a  "real" video resolution such as 1920x1080.
Based on its size, I'd guess you only have 2 frames in there. That would be stretching a bit if you need a real video file. A low bandwidth (25Mb) AVC source of this size would be 100x bigger.

Try using a standard HD res at the source, a bigger bitrate and more key frames.


How to make a video presentation with the possibility to go to the next or the previous "video-slide"? I've tried to make a Power Point presentation but I've to many videos and rendering inside so the presentation doesn't have a good portability and continuity. I would like to make directly a video, the problem is that in a video I can't go to the next or the previous slide (that in this case can be a piece of video or a conventional "static" slide with text...) like in a presentation. What software or tool can I use to have this feature in a video. Best solution would be: use the same command (right/left arrow, mouse click...) of the PP presentation to go to the next or previous video slide.

I recently saw this page:

https://hacks.mozilla.org/2014/08/building-interactive-html5-videos/

Basically it uses the track element within the video element to make clickable "skip points" in the video. Javascript and html5 (with video) are pretty much amazing these days and with a little bit of experimentation I am sure you can get what you want. (Like on skip event pause the video if playing etc.)

Here is the relevant code from that page modded to your needs:

  <video width="480" height="204" poster="assets/sintel.jpg">
    <source src="q1fx20VZ-kNspJqnJ.mp4" type="video/mp4">
    <source src="q1fx20VZ-27m5HpIu.webm" type="video/webm">
    <track src="assets/chapters.vtt" kind="chapters" default>
  </video>

The contents of the vtt file look like this:

WEBVTT

1
00:00:00.000 --> 00:01:42.000
Opening credits

2
00:01:42.000 --> 00:04:44.000
A dangerous quest

3
00:04:44.000 --> 00:05:50.000
The attack

4
00:05:50.000 --> 00:08:24.000
In pursuit

5
00:08:24.000 --> 00:10:13.000
Cave Fight

6
00:10:13.000 --> 00:12:24.000
Eye to eye

7
00:12:24.000 --> 00:14:48.000
Ending Credits


Remove an image through subtraction? Firstly, I'm no video professional, I'm an audio professional. Video theory is a dark area for me. So I will use an audio-type analogy in this question.

In audio editing, it is possible to subtract one waveshape from a bunch of other waves by inverting the phase of the wave(phase subtraction). While this is a simple, easy to understand process, due to my lack of knowledge of digital video processing, I am unsure if this process is an available tool in video editing. My logical mind tells me that it is. I know in nature, like in bubbles, phase interactions cause interesting effects.

I need to use this process on a video to remove the axis scales from a 3D spectrogram, so that everything else in the video except the axis scales are left.

For this I assume I need an isolated image of the thing I want to subtract i.e. the axis scales. I'm using Adobe Premiere Pro or After Effects, whichever is best for this. The Image I want to remove is stationary in the video.

Any advice on how to do this in Adobe AE/PP if it can be done is appreciated.

It is possible and works in a similar manner. What's different is that normal pixel values in video are always positive, whereas it's normal for audio to go both positive and negative several thousand times per second.

If you have a copy of the axes without the spectrum, you can overlay the image with the spectrum on top of the image of the axes and set the blend mode of the spectrum image to "difference." That will subtract the image of the axes from the spectrum image and leave black where the axes were.

If you don't want black, but some other color, you can use an image mask that sets the axes to an alpha value of 0 and the rest of the image to an alpha value of 1 (or 255 if you're working in 8 bit per channel mode). Then put some other color underneath the masked footage.

EDIT: I forgot to mention that the image of the axes alone should be black wherever you want the original image to come through. (Because you're then subtracting 0 from the original image in those areas.)