What is best setting of Nikon D3300 camera to shoot daytime video from a moving car? I want to shoot outdoor road videos looking through windshield of car in broad day around noon time moving at about 25 MPH. I want to document what the road and surrounding areas look like for web display which means videos would be downscaled. What is the recommended settings like mode, focal length, shutter, aperture fstop etc?

Shooting through a windshield is a very dicey proposition.  There is an amazing amount of glare that you don't see when you are in the car, but which you will see when you look at your camera footage.  A far better solution would be to mount a GoPro (or some other small, disposable camera) on the exterior.

Nevertheless, if you insist on using a DSLR, then only with a wide-angle lens will you get "the surrounding areas" to give context to your road.  You can think of angle of view this way: if you have a 90 degree field of view, then you have (in the left half of the frame) something that sees the range from 45 degrees left to the center of the road and (in the right half of the frame) something that sees the range from 45 degrees right to the center of the frame.  45 degrees to one side or another is not very wide-angle (compared to turning your head and looking sideways), but wide enough to show some very limited context.  To achieve that with a DX format, you need a 10 or 11mm lens.

For shutter speed, you don't want too much blur.  25 miles per hour is 36.7 feet per second.  Since you are shooting at max 45 degrees, 36.7 * cos(45) = 26 feet per second.  If you shoot at 60 fps with a 180 degree shutter (1/120th of a second), then the largest blur on the sides will be 26/60 = 2.5 inches.  2.5" may be an acceptable amount of blur for a building-sized object that's on the way out of the frame.  If you look closer to the center of the frame, say 22.5 degrees off center, the blur will be 36.7 * cos(67.5) = 1.4 inches.

Wide-angle lenses tend to have deep depths of field, so you can safely use an aperture that gives you the right exposure (but check your depth-of-field charts).

But a GoPro will give you a better result for many reasons, not least because they have built-in very wide-angle lenses.


How to get the highest possible quality out of a MP4 file I took over the editing for a project recently and I wasn't given the raw files. All I was given was the partially completed MP4 file. I used Final Cut Pro 7 to complete the project edits. When I exported the file, I exported using Quicktime Conversion to create a .mov file.

The issue is that this file must be broadcast quality and it just failed QC because parts of it are pixilated.

I'm wondering, is there a way to export the file - which looks perfect on my end - so that it isn't pixilated and it passes QC?

If the pixelation wasn't in the sources you had, then it was probably introduced by the video encoder you used to export.  (Presumably Apple's h.264 encoder, creating a .mov with an h.264 video stream, as opposed to one of the many other video codecs that the mov container can hold.)

Video encoding always trades off CPU time vs. bitrate vs. quality.  Using more CPU time can get better quality at the same file size.  Different encoders (x264 vs. mainconcept vs. apple vs. IDK what else) will have worse or better achievable tradeoffs.  x264 is the best H.264 encoder for pretty much everything, esp. if you care most about final quality per file size.  It's free and open source, so there's no reason not to use it.

Look for a slider to turn up the CPU usage and/or bitrate until the resulting encode is high enough quality.  I'm not going to go into any more detail, just google for video encoding guides to find out more.

edit: As stib points out, you might well be in a situation where your output file is going to be transcoded before broadcast, in which case you should just turn up the bitrate as high as is reasonable, to minimize generation loss.  Prores has no advantage over h.264 for this purpose, though.  Your file will be decoded once, at full rez, in order.  Prores is intra-only, and can decode faster at reduced rez, but gives up quality per bitrate in order to gain those features.  h.264 and prores both support bit depths higher than 8bit per component (subject to encoder/decoder support), which may be relevant if the TV station that will broadcast it wants to mess with the colors during transcode.  If they won't, then the small compression advantage of 10bit h.264 is of low value, given how much slower x264 is when encoding at higher than 8bit.

prores is (slightly) lossy, but as far as I know, h.264 at the same very high bitrate will be even less lossy.  You can even use x264 to produce lossless h.264, if the people you're sending it to can decode it.

If you were sending it to people that were going to do something and save that as prores themselves, then using prores yourself might make sense.  I think I read that prores is designed to stop losing quality for multiple generations of transcoding.

If you're going to permanently archive the output file, spending some more CPU time (and using x264) to get good quality per bitrate might still be useful.  But if you're instead archiving the FCP project and sources, then that doesn't matter.

end of edit

If you don't want to set up x264 for Final Cut Pro, or export lossless and feed that to x264, then similar controls for the h.264 encoder that comes with FCP probably exist.  I don't use FCP, but this is really a video-encode-quality question, so I'm answering anyway.  An answer from a FCP user would probably still be useful.

BTW, one case where x264 isn't the best choice is encoding a movie for your mobile device or something where you're only going to watch it once, and large filesize doesn't matter.  Then a GPU encoder like Intel quicksync can throw enough bitrate at the video for it to look good enough on a tablet or phone, but be smaller than the dvd or blu-ray source.

If you're doing "encode once -> watch many", like for broadcast, it makes sense to use as much CPU time as you can, to get the best quality for your target filesize (2pass mode).  Or to get the smallest filesize for your target quality (CRF mode).


Why do high FPS videos look less blurry than real life? Quickly wave your hand in front of your face right now. Looks really blurry right? Now watch a 60 fps video. How come it looks so smooth? To me 60 FPS videos look even smoother than real life. Why?

Well this answer is just based on my knowledge of video cameras and is largely a best guess.

In video cameras motion blur is not (necessarily) determined by the fps but by the shutter speed (in cinema: shutter angle). The quicker/higher the less motion blur (I guess you can liken this to a screens refresh rate). Thus, things filmed at 24fps (cinema standard) but with a faster shutter speed will have a sort of other-worldly appearance as if everything is faster than in the real world. A good example of this is the opening Normandy scene in Saving Private Ryan.

When you combine a fast shutter speed with more than traditional fps (generally anything over 30) the motion looks surreal. Likely any other phenomenon is related to the way we process images and that I cannot adrquently speak of as I believe research in this field is largely mixed.

Here is a good link on shutter speed: http://www.red.com/learn/red-101/shutter-angle-tutorial


Premiere Pro CC export produces dark, muddied video I've dug around numerous forums and have had no success finding a solution to my issue - .mp4 files color corrected in Premiere and exported in H.264 end up being unacceptably dark, the colors crushed.  There are a lot of conversations from 3 years ago about exports being lighter, or solutions offered on a Windows platform (I use a Mac), lots of complaining about Quicktime, but nary a fix for what ails me.

Here's an example of my issue:

Top left = Premiere program monitor; Top right = Quicktime playing the .mp4; Bottom center = Youtube (obviously).

In reading forums, I wonder the issue is that I'm editing in 0-255 rgb range, but it's exporting in the 16-235 range.  Or vice versa?  I'm fairly new at this and while I'm pretty confident in everything else regarding video production, I can't figure out what's going on behind-the-scenes in Premiere that would cause this.

I have found each video example to be unchanged from Mac to PC, on Safari, Chrome and IE11, exported for Vimeo or Youtube, on the MacBook Pro screen to two differing-model dell monitors.

I work on a 2013 MacBook Pro, with an Nvidia GeForce GT 650M.  The drivers are up to date.  There are no meaningful graphics card settings on OSX.

At first I thought that Quicktime as a player doesn't have anything to do with it since it shows up the same on Youtube.  It must be in the file.  Then I imported the .mp4 back into the project and the color/white balance looked fine.  So now I have no idea.

Thanks in advance.

Andrew

In my experience Quicktime always produces incorrect shading and color with video- period. It shouldn't be used to assess what really "is there".

First, go into Bridge. Under EDIT, make sure you've synchronized all your color settings for all Adobe Products, and that you're using WEB AMERICAN (Monitor Color for sRGB).  That would be the correct profile for web content like youtube.

After that; try re-out putting. Also; you can check your NVIDIA settings; but you want to allow applications to control color; so it could be that your system is simply using a different color profile or an expanded color gamut for web vs what Adobe is using.

But I'd shy away from using QT for viewing files (or anything MAC for that matter); having switched over to only using Windows based workstations so many problems like these have been solved for us.

Hope this helps.


VHS tape has one "cog" blocked off - can't play it I'm converting some old VHS tapes to DVD, and all is going well.

The last VHS tape, however, is different than the others. Where you would normally have 2 "cogs" for the two reels, this tape only has one, while the takeup wheel "cog" is more or less blocked off:

When I insert the tape, it doesn't go down all the way into the player (I'm assuming because the plastic piece above is blocking where the gear would normally go). The VHS player panics, and spits the tape out.

How can I resolve this? And to satisfy my curiosity, what is this piece and why is it there?

So, I posted these images to Reddit under /r/whatisthisthing, and the answer that came back was obvious once it was offered:

Someone has taken a normal tape apart and re-assembled it with the take up spool upside-down.
It can't be a cleaning tape because it will not engage with the take up spool drive. A machine might just spit it back out but it could slam into the drive mechanism and cause some damage.

You will have to take the cartridge apart and carefully flip the spool over. No telling what other nonsense might be going on inside that cassette, however. So standard YMMV disclaimer applies.


How can loop animations with a different start and end point in after effects? I use normally: loopOut('cycle') expression to loop a movement. But sometimes I want to loop an animation like this:

1-3 frames -> rotation 30deg
3x loop a full rotation
after looping -> add 10 other frames and
make rotation 120deg

How is it possible to loop between this actions and not using copy+paste?

Here is a link to my work

I loop the arms motion, but as you see in the first frames the left arm has to wait until the right arm does the first half of the motion. If I add a half motion to the left arm I can't loop it. I would have to avoid copy+paste because I want to loop it 40 times. At the end of my animation I also need a different motion with the right or left because the swimmer has to touch the wall with two hands. I hope, I was clear.

Using time remapping could be a solution. You animate one full circle of the animation and precompose this. Then you time remap that layer and use loopOut('cycle').


How to Fix Warp Stabilizer Incorrect Rotation I am using Warp Stabilizer on some footage and it's almost perfect but there's a random erroneous rotation in the middle.

Is there a way I can fix this manually, maybe go into the keyframes or correct some points?

Edit: or just disable rotation all together? (while keeping position and scaling)

Here is an example clip

(btw I lowered the frame-rate to make the stabilization faster)

Thank you!

sorry I don't use this forum and have zero time to answer, but from the clip you posted I'd strongly suggest you don't use warp stabilizer - instead use "stabilize motion" and then make sure to check the "rotation" parameter so that you are given a second tracker - then once you've stabilized the position and rotation of the footage you'll have to do a little extra to manually slide the footage left or right depending on where the camera goes (look into stuff like "setting a null as the target for tracking motion" and you'll get a better understanding of all this stuff).


Concat overlapping videos with ffmpeg using python3 I have a number of videos that overlap in time that were downloaded from an online video stream:

0m00s  - 15m10s
14m50s - 30m20s
...

The first few seconds (usually around 20 seconds) of a video segment duplicate last few seconds of the previous segment.

I'd like to concat the video segments and form a single video file without duplicate parts. I can do it programmatically using ffmpeg libraries to find the cut points by minimizing error between a frame of the current segment and the last frame of the previous segment.

Is there a way to achieve this with an ffmpeg command?

I wrote the following script to solve my problem. It uses framemd5 checksums to find the inpoints in time and then uses the concat demuxer (thanks @Gyan for the tip!). I also created a gist with a more complete version that supports exact PTS inpoints using concat video filter; computing inpoints using explicit frame differences.

# Usage: ffmpeg $(python3 script.py input1.mp4 input2.mp4) -y -an output.mp4

import os
import sys
import subprocess

ffmpeg_concat_echo, md5_last_frame = '', None

for video_path in map(os.path.abspath, sys.argv[1:]):
        framemd5 = subprocess.check_output(['ffmpeg', '-nostats', '-hide_banner', '-i', video_path, '-an', '-f', 'framemd5', '-c', 'copy', '-'], stderr = open(os.devnull, 'w'))
        tb_num, tb_den = 1, 1
        inpoint = 0.0
        for line in framemd5.split(b'\n'):
                if line.startswith(b'#tb'):
                        tb_num, tb_den = list(map(int, line.split()[-1].split(b'/')))
                elif line and not line.startswith(b'#'):
                        splitted = line.split(b',')
                        md5 = splitted[-1].strip()
                        pts_time = float(splitted[2]) * tb_num / tb_den
                        if md5_last_frame is not None and md5 == md5_last_frame:
                                inpoint = pts_time
        md5_last_frame = md5
        ffmpeg_concat_echo += 'echo "file {}"; echo "inpoint {}";'.format(video_path, inpoint);

print('-nostats -hide_banner -avoid_negative_ts make_zero -fflags +genpts -f concat -safe 0 -i <({}) -c copy'.format(ffmpeg_concat_echo))


Cannot export video file in correct resolution I am following this tutorial on how to cut out audio from my video (I actually wanted to cut out just part of audio but i know how to do that so its not a problem)
@ 2:55 the video shows a window which does not appear when i drag and drop my video in. :(
however when i right click on my video bar and click properties it still says the video is 480x800
However when i try to export the video the resolution of the original video appears as 720x480
In addition when i go to sequence>sequence settings the video frame is grayed out at 720 and 480 so i cannot change the settings.
When i try to export the video in the 480x800 resolution it just appears as a small video in the middle with whole bunch of black space around it.
I just want my exported video to be the same as the original video but i cant figure out how to do that.
Im using adobe premiere-cs6 but i need 50 more reputation to create that tag.

From your question, you want to remove the audio from a video clip, using Premiere.

Start a new sequence, and drop your clip into it. There should be audio and video streams in the timeline.

Using File > Export > Media, there is a very simple way to remove the audio.

Using these toggles here, you can disable audio from being included in the export.

However, you will also want to make sure that your export settings are the same as the video clip.

As for setting a codec, I suggest either:

Format: QuickTime / Codec: Animation - if you need a high-quality, large file size video for further editing.
Format: QuickTime / Codec: H.264 - if you need a file ready for playback, distribution, or internet upload.


Does the M4V file type have direct support for Audio? I am working with a video vendor who just ripped a dvd and sent me BOTH m4v files AND aac files (audio and video separately),. When I asked him why he did not just send 1 m4v file with the audio and video in ONE FILE, he wrote me back this (Which I need to confirm is true or false):

  .M4V is a video format that doesnt directly support audio so the computer automatically rendered the audio files out as .AAC. What you
  say is an .MP4 format is really just the "file type" and not the
  extension itself.

Doesn't sound quite right, but I am not a video pro. But I do not want to have to splice all these files together again.

Please advise: Is his statement (above) correct?

Thanks, sleeper

I find the m4v extension a bit confusing.

For MPEG-2, the .m2v extension is associated with a raw video stream. Those files can have only video.

Now for MPEG-4, Apple uses the .m4v extension as a container format, and in fact if you rename an .m4v file to .mp4 it is likely to play on players that only read .mp4 files, since the two format are essentially equivalent.

I think you would need to check this .m4v file and make sure it is really the container format, and not an elementary video stream similar to what you find in .m2v files for MPEG-2.

If you feel comfortable inspecting files with a hex editor, just open this .m4v file, skip the first four bytes and check if the next four are the letters 'ftyp'. If they are, then you have an MP4 container file that should have no trouble holding audio along with the video. If, on the other side, you've got something else, then you may have an elementary stream, in which case you may want to recommend to your vendor to use a different extension for these files. Using .avc is probably more appropriate for an H.264 elementary stream.


Best medium for mixed content - High quality pictures and SD video Should I try to output family movies/slideshows to a DVD or a Blu-ray, if my video content is mostly SD, and some of my images from are high-quality RAW photos?  I'm thinking on just going the DVD route if the quality potential won't matter much?  Thanks for your opinions.

Please also suggest the best authoring software to use at a good price if you have opinion as well.

It depends on your goal:

If you must deliver to viewers with only a classic DVD player then make it a DVD.
If they only have a Blu-Ray player then make it a Blu-Ray.

For content preservation I would recommend to basically write all original content onto a disk with highest possible quality in wrappers/containers that are widely supported (high-quality JPEG for photos and MPEG4 or MPEG2 for videos). Then most modern players will be able to present the content, as well as allowing you to keep good mezzanine quality.


Is mp4 or avi format convertable to raw? Can I convert it to a raw video ?

Arduino Drone Next Step| Buying New Item(s) and Public Flight

No, if you don't record in raw, you can't get back to it.  That's why people go through the headaches of recording in RAW.  RAW is the actual photosite exposure data and isn't actually a usable image on it's own.  Imaging sensors don't pick up all colors on each individual pixel.  Some pixels pick up red, others blue, others green.  Some fancy designs may have one or more other colors as well.

The data about the values of each of these photosites (each of which will eventually be a pixel) is fed in to an algorithm that looks at neighboring pixels and figures out the RGB value for each pixel.  During this calculation, the information about the original values is lost and only the RGB pixel values are kept.

On some sensor designs, it might still be possible to work backwards if you had full bit depth RGB data (though many can't), full understanding of the filter and conversion logic and avoided certain exposure situations, however you have an additional problem that the video has been put through one or more rounds of compression in addition to being stored in a color format that does not preserve the full bit depth of the color data.

This means that the necessary color information does not exist anymore no matter if your particular camera happened to use an algorithm that was reversible (which is itself unlikely).

Practically speaking, there is no way to get back to RAW from a processed video.  If you want to work in RAW, you need to start in RAW.

If you don't have an option to work in RAW and are trying to maximize your color correction ability, shoot with the highest color depth you can and shoot log color to avoid losing information in the brighter and darker areas.  You'll end up with a little bit less color information in the mids of the finished product, but it will buy you a ton of room for tone adjustment in post (and if you are able to shoot 4444 and are editing to a final output of 422 or lower you probably won't lose a ton anyway.)


Premiere distorts picture while paused Premiere is distorting footage while paused, making color grading ridiculously challenging.
Whether the media is playing in the source monitor or the sequence monitor, the picture is pixelated and tinted red and yellow. While playing, the picture looks normal. Here are two screenshots from the Black Magic Cinema Camera. The same happens with the 5Dmk3 H.264 footage.
Paused

Playing

Troubleshooting
Here's what I've tried and the results so far:

I reinstalled Premiere Pro CC 2015.
I tried from different cameras. The issue persists in every case. I've tried with H.264 from a Canon 5Dmk3 as well as with ProRes 422 HQ from a Black Magic Cinema Camera.
I tried footage from different shoots. Same problem.
I created a brand new project and imported new footage. It still distorted while paused.
I rebooted my Mac in safe mode, created a brand new project, and the picture wasn't distorted. It was, however, cropped down to only show 25% (the lower-left corner of the picture).
I tested in Final Cut Pro X 10.2.1. No problems here.
I tested in Speedgrade CC 2015. Same problem as Premiere.

Normally it renders OK, but when I've tried to render to MPEG the distortion persists in every 2nd frame.
My setup
Here's the hardware and software combination I'm running on. If I hadn't successfully eliminated the distortion in safe mode, I'd think my OS was the issue. It may be, but this issue did not occur in 10.11's safe mode.

Premiere CC 2015
OS X 10.11.5 (the public beta of El Capitan)
MacBook Pro (Retina, 15-inch, Late 2013)
2.6 GHz Intel Core i7
16 GB 1600 MHz DDR3
NVIDIA GeForce GT 750M 2048 MB

My question
What next step(s) should I take to resolve this issue? (Or, what else can I do to understand it more deeply?)

According to Adobe, it's a bug. Until Adobe fixes this bug with an update, the workaround is to switch off GPU acceleration in Project Settings.


Reverse order of clips when importing from card or camera in Final Cut Pro X? When I'm doing to-camera commentary in my studio, a regular part of my workflow is to record some footage on my DSLR and then import it immediately into Final Cut Pro X. I'll often need another take (or ten) before I've finished so it's really annoying that when FCPX fetches the files it does it in the order they were shot, so the file I want is always the last to appear.

Is there any way to make Final Cut Pro X fetch the most recently recorded file first instead?

I don't think it's possible. In my experience the contents isn't loaded in any particular order, so setting the order to ascending content created date doesn't actually change the order the files are loaded. You can still try setting the date order to ascending if you wish: click the  button on the status bar then click the ‘content created’ header to sort ascending.


Possible to stream/append images into an existing mp4? I've been working on a service that downloads a number of images, saves them to disk, and then uses ffmpeg to create an animation (gif or mp4). This can be fairly intensive in terms of memory and CPU usage.

Are there any methods that would allow me to dynamically append and encode a new image to the animation as they're ready, rather than having to read all of the images at the end and generate the animation at the end?

Everything is possible!

Let's image, you have a /directory/ per video animation and files like img0001.png, img0002.png. You have 3 ways:

Wait all images, img0001.png, img0002.png ... img0100.png to be in directory, run ffmpeg, get mp4 and remove images (current way)
Write application in C with ffmpeg libraries: wait every single image, decode it in memory, remove from disk immediately and feed to encoder in libavcodec. When you got last image, for example img0100.png, you feed it to encoder and call something like flush() to complete image, so your mp4 will be completed. Drawback of this method is memory consumption - your process will live until all images processed, so if you downloading it long time, process will consume some memory all this time!
You can try to implement same in bash script using pipes:

Here we got any input, list files for example:

`    ls -1 | grep "jpg$" | while read filename; do`

Then unpack images:

`    ffmpeg -v 0 -nostdin -i "$filename" -f rawvideo -s 120x60 -pix_fmt rgb24 - `

And encode it:

`    done | ffmpeg -nostdin -f rawvideo -s 120x60 -r 10 -pix_fmt rgb24 -i - -s 320x240 -vcodec libx264 -y res.mp4`

I think, you got idea.


Power for lav mic plugged into a Zoom H5? I have a handheld Zoom H5 recorder and just ordered a lav mic (Voice Technologies VT4001).

The Zoom's spec sheet lists its inputs as 2 "XLR/TRS combo jacks" capable of providing phantom power at +12V, +24V and +48V.

I will be using the lav wired.

Question: which is the simplest way to connect and power this mic from this recorder? Do I need some sort of adapter or will a simple mic jack <=> TRS cable do?

You will need an electret power supply that accepts phantom power and then will hook it up via a standard XLR cable to the H5.  If you have the bare wire version, you will also need a connector to put on the bare wire so that it can tie in to the electret power supply.  You will also need to make sure that +48v phantom power is turned on on the H5.  (Alternately you could use a battery powered electret power supply, but I'd recommend sticking to using phantom since it is available.)


Periodicals/magazines/blogs for cinematography? I want to stay up-to-date on cinematography techniques -- not just regurgitated press releases on camera technology. What regularly updated resources (not books) should I follow to continually learn the craft of cinematography?

Note: this is a re-post of a question that was closed as off-topic on Photography - Stack Exchange.

For basics in digital cinema the Vimeo School is a great start.

There are tons of blogs for cinematography.

One of the most interesting blogs that covers gear and on the set experiences
is by noted DP, Philip Bloom, a real major force in modern digital cinema:
http://philipbloom.net/blog/

Coen Brothers too:
http://thecoenbrothers.blogspot.com/?zx=2bb8d66a241d6286

For me the best way to find what's up is to see if your favorite
director, studio, camera manufacturer, or whatever has a blog via Google.


how to animate dots in sequence I'm new to After Effects and wondering how that's possible to animate opening for this map so each dot appears individually? I know how to make the opening using the mask but it shows the edges while I'd like to have "popping one by one dots" animation.Please see image below:

This tutorial can help you:

You will find there how to make dotted effect from scratch (use outlines of the map). Then you shall add some key-frames for animation.

To make dots appear more random, you can use Fractal Noise as animated mask.

Good luck!


FFMPEG Loop Concatenate Video to Specific Length I am trying to use FFmpeg to generate for example a 1-hour video from concatenating a 1-second input video over and over and over again.
The problem is that the length of my input video is of various lengths so I can't just hardcode it to make it concatenate 3600 times.
My approach is:
1.Acquire the length of the input video (in this example, 1s)
2.divide the target length by the length of input video (in this example, 3600)
3.Let FFmpeg concatenate for (3600) times with -vcodec copy -acodec copy
I am using Android Studio and the com.writingminds:FFmpegAndroid:0.3.2 module
Any ideas would be appreciated.

Use stream_loop to loop the input indefinitely and set output -t to limit the duration.
ffmpeg -stream_loop -1 -i input -c copy -t 3600 output


Is 4K good enough to choose for special footage such as weddings? Resolution is obviously better in 4K but can anyone give some insight as to whether other factors of video quality are being compromised? If so, does it make sense to record in 1080?

Where are you planning on exhibiting the footage? In my experience, the average consumer has a low-quality TV they bought because of the price, and they have the factory settings that look awful because they don't even know that they would want to change them, let alone how that would happen. In my opinion you're wasting your time because your client probably won't be able to tell the difference.

On the creation side, you're multiplying the amount of data captured by 4. That increases the cost of filming (more memory cards to save it), storage (more hard drives to use while editing), and editing (need a better graphics card, more RAM, and likely more time).

If you have clients who will truly benefit from 4K, by all means, use it. But if you're doing typical videos for the web, corporate or home televisions, it's probably not worth it. If you're creating content for large outside displays that actually reach above HD, or for professional projection in a theater, then it could be worth it.

FWIW, most television shows are shot in HD, and even some feature films. I've never heard anyone complain about the quality because of the lower resolution. If I recall, parts of the first Captain America movie were shot on a Canon 7D, which only does HD. I know of nobody who said those parts were terrible or even noticed them. (Here's an article about it on Canon's web site.)


FFmpeg concat plus video inside video with different times I have 4 files with same encoding to concatenate

  "video1.mp4": duration 3 seconds. Show time from 00:00 to 00.03
  "video2.mp4": duration 1 second. Show time from 00:01 to 00.02
  "video3.mp4": duration 2 seconds. Show time from 00:01 to 00.03
  "video4.mp4": duration 2 seconds. Show time from 00:03 to 00.05

What commands to get the following output?

00:00

00:01 to 00:02

00:03

00:03 to 00:05

Basic syntax is

ffmpeg -i video1 -i video2 -i video3 -i video4
       -filter_complex "[1]scale=0.40*iw:-1,setpts=PTS-STARTPTS+1/TB[v2];
                        [2]scale=0.40*iw:-1,setpts=PTS-STARTPTS+1/TB[v3];
                        [0][v2]overlay=x=W-w-20:y=H-h-20:eof_action=pass[m2];
                        [m2][v3]overlay=x=W-2*w-40:y=H-h-20:eof_action=pass[m3];
                        [m3][3]concat=n=2:v=1:a=0"   out.mp4

I assume all videos have same resolution and framerate. I've scaled videos 2 and 3 to 40% before overlay and offset their start time to 1 second.


What's the best free video editor for a music slideshow? I am looking for a FOSS video editor to make a slideshow with. I want soemhting that's easy to use with the ability to have standard timed transitions across all clips. What's the best option?

In my opinion, it is the best idea and the fastest Adobe Premier Pro software
Its great user interface can be the best idea for you
Da Vinci Rizalo and Final Cut software are also great
Good luck


mp4 - Codec or Container Please explain, so confusing. I get that AVC is a video format, MKV is a container (that can contain mp4 video, FLAC audio etc.), but what is mp4 then?

MP4 has not really an official meaning, but it adds a lot to the MPEG-confusion. MP4 refers to MPEG-4 which is a huge collection of video-related standards that has been growing for more than 20 years.
MPEG-4 part 14 container: takes an .mp4 file extension, therefore often just called MP4, if it contains audio, it can also have the .m4a extension, for video .m4v, and others (.m4p, .m4b, .m4r). the container format is a derivative of Apple QuickTime's container format (.mov).
MPEG-4 Part 2 video codec: Most often just called MPEG-4, sometimes it also takes the name of the encoder software: Xvid, DivX... Became the first de facto standard for web video.
MPEG-4 Part 10 video codec: also called MPEG-4 AVC and (ITU-T) H.264, and by the name of it's most popular encoder software: x264. De facto standard video codec today: video conferencing, smartphone videography, Web, Blu-Ray, TV, camcorders. Almost all video capable devices ship today with H.264/AVC hardware codecs by default besides newer but still less common codecs like VP9, HEVC or AV1. The successor for H.264/AVC has been coming since 2013, but just for fun they decided not to call it MPEG-4, but MPEG-H Part 2 also known as ITU-T H.265 or High Efficiency Video Coding (HEVC).
AAC (Advanced Audio Coding) is often called MPEG-4 Audio. It is probably the most prominent amongst the many codecs standardised in MPEG-4 Part 3. It often uses the file extension .mp4 or .m4a
I'm not even going to start about all the other MPEGs :-)
TL;DR
MP4 could mean a video codec, a file that contains video and/or audio or even something else. It's not a clear term.


Change default audio track in mp4 video I often download mp4 videos with multiple audio tracks.
Is it any way or some tools with explanation to change default audio track ?

Use FFmpeg:

ffmpeg -i input.mp4 -map 0 -c copy -disposition:a:0 0 -disposition:a:1 default output.mp4

Audio tracks (streams) are numbered from 0.

Supposing the input video has 2 audio streams, and the default audio stream is 0, we need to

remove the “default” disposition from it (by setting it to 0: -disposition:a:0 0) and
set it to the audio stream 1 (by setting it to “default”: -disposition:a:1 default).

In general, remove the “default” disposition from all audio streams except one, and set it for it.

Note:

Not all media players honor default audio stream — for example Media Player Classic don't honor it (but you may set the preference by the language of audio streams), while VLC Media Player and FFplay do.

Proof (note the location of the “(default)” tag):

ffprobe -hide_banner input.mp4

gives (among others)

Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 69 kb/s (default)
Metadata:
  handler_name    : SoundHandler
Stream #0:2(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 74 kb/s
Metadata:
  handler_name    : SoundHandler

while

ffprobe -hide_banner output.mp4

gives

Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 69 kb/s
Metadata:
  handler_name    : SoundHandler
Stream #0:2(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 74 kb/s (default)
Metadata:
  handler_name    : SoundHandler

The numbering here numbers all tracks, so #0:0 (omitted from the FFprobe outputs) is the first (video) track, and #0:1 and #0:2 are audio tracks.


OBS Studio: desktop audio falls out of sync I have an interesting problem:
When I stream to Twitch (or record), my desktop audio goes out of sync with the video over time. The microphone is perfectly synced the whole time.
Both OBS Studio and "playback device->Speakers" have 44.1kHz.
I have device timestamps on, started with it off, changed it because of the desync.

So with everything I've tried I'm not sure if I messed anything up, but....

Turning off "Use device timestamps" in the properties of "desktop audio" fixed the problem.


Star Trek Continues: ffmeg dvdsub: overlapping subtitles So I've downloaded the free fan-created Star Trek Continues Blue-Ray ISO for Episodes 1-3 and I'm trying to convert the FHD 1920x1080 to SD 960x540 to be able to watch on my phone:

ffmpeg -canvas_size 960x540 \
-i /media/STC_VOL1_BR/BDMV/STREAM/00000.m2ts \
-map_metadata -1 \
-c:v libx264 -map 0:0 -strict -2 -r 24 -s 960x540 \
-c:a libmp3lame -map 0:1 -b:a 384K \
-metadata:s:s:0 language=EN -c:s dvdsub -map 0:2 \
/media/Videos/Star\ Trek\ Continues/S01E01\ Pilgrim\ Of\ Eternity.mkv

but after a few seconds of watching the converted mkv, the subtitles become:

unreadable due to overlapping
are slightly big (no issue)
shifted to the right and bottom of the screen

What am I doing wrong?

Note: I've only ever dealt with srt subtitles and I  know that dvdsubs are images, so that's why I thought the canvas_size parameter might be of help, but it makes no difference.

Technically the cleanest look with these subtitles would be to:

Extract the subtitles
Turn them to text using your favourite OCR application
Carefully review and edit the text
Burn them back into the media stream in the size, colour, orientation and format of your choice

This is a large and time consuming job which I have personally undertaken in the past but is probably overkill in this case.

The better option is to simply add in the FFmpeg option -fix_sub_duration (placed before the input file options) and this will fix the doubled up subtitles as I illustrate below, and make the subtitles easily readable:

The details of the -fix_sub_duration option can be found in the FFmpeg-all man pages but I have taken the liberty of quoting these details here:

  -fix_sub_duration

  Fix subtitles durations. For each subtitle, wait for the next packet in the same stream and adjust the duration of the
  first to avoid overlap. This is necessary with some subtitles codecs,
  especially DVB subtitles, because the duration in the original packet
  is only a rough estimate and the end is actually marked by an empty
  subtitle frame. Failing to use this option when necessary can result
  in exaggerated durations or muxing failures due to non-monotonic
  timestamps.

  Note that this option will delay the output of all data until the next
  subtitle packet is decoded: it may increase memory consumption and
  latency a lot.

You will note that this is the first of the Advanced Subtitle options, the second being the -canvas_size that you have already used...


White balance vs color correction I understand that it is a newbie question and if googled there are tons of articles regarding this, yet I am a bit confused with the answers given.
So, in every video post production there is almost always some color correction. In this case, why is white balance correction necessary? Especially if a color card is used and the colors of the video are adjusted to the card, why "bother" with the white balance?
Yet, I have seen videos concerning video editing and I noticed that both white balance and color correction appear, with WB preceding.
Finally, is there a standard procedure regarding the work flow of the color adjustment?
Thank you in advance.

Regarding the standard procedure, the short version is:

get the colour looking correct but neutral, which is when you do corrections for white balance and exposure problems. The footage will look "natural" at this point.
match the colour between shots (this is really part of step 1).
apply a creative colour grade, to achieve the look that you want. You can do this on a scene by scene basis, rather than shot-by-shot.

Usually getting the colour looking natural is the best place to start when applying a "look". It's very hard to get a consistent look between shots that are not corrected to match each other.


By which software/website this animated video was created? I'm looking for a software or online website that creates animated videos that supports the integration of a business logo.

Example - Facebook Video

I found many online services that create animated videos similar to this but with slightly lower quality. So I'd appreciate it if anyone could tell what is the name of the software or the website this page uses for creating their animated videos.

As for video editing, this is pretty straightforward. The frame and the flowers are simply an image that has an alpha channel applied to it to make the contents of the frame opaque. The images in the frame are static (as in not animated) images with crossfade transition (as well as a static background image). You can do this with pretty much any video editing software.

As for the illustrations, I'm pretty sure they were created with Adobe Illustrator (or any other vector graphics software). While the editing for this video is super easy and can be done by anyone, I would recommend you hire a professional illustrator if you want to create something similar but don't have experience in that area (and don't want to have to rely on stock images/illustrations).


BlackMagic hyperdeck Connection failed I've got a Blackmagic hyperdeck and a computer. Their are both connected on the same network.
The network settings of the hyperck are :

Remote : ON
DHCP:OFF
IP address:192.168.1.100

I can ping the ip address provided by the hyperdeck.

$ ping 192.168.1.100
>>11 packets transmitted, 11 packets received, 0.0% packet loss

But when I try to connect myself with telnet for a TCP connection it failed :

$ telnet 192.168.1.100 9993
>>Trying 192.168.1.100...
>>telnet: connect to address 192.168.1.100: Connection refused

Do I have to configure something else on the hyperdeck or the computer ?

We made a new set up but my computer had a new IP which was the old hyperdeck IP. And the switch of the hyperdeck was off.
So if was pinging my own computer.

I switch on the switch, change the ip adress, it work back again.


Adobe Premiere clip duration lag Sort of a strange issue with Premiere. As you are aware you can change a clips duration by sliding the clip from the end back or fourth. For some reason, in a particular project this takes at least 3 seconds to move in or out (almost like lag). I've confirmed that in other projects this doesn't happen, so it wasn't something I changed in the settings. Have any of you ever experienced this or have any suggestions?

I already did a lot of work in the project, and I would hate to do that over again.

Solved: issue was audio effect on the master that was causing the clip duration change lag. iZotope RX was the plugin causing this if anyone is interested!


Brightness and contrast ratio, inversely proportional? I'm comparing the features of 2 projectors, which are very similar between them. They both have 1300 lumens.

However I was surprised to see the following values:

Projector 1
Brightness (lm) 3000
Contrast ratio 2000:1

Projector 2
Brightness (lm)*1*2 1300 (Max)
Contrast ratio*1  3600:1

What does this mean ? They are both for home videos, but is the second one more suitable to darker environments, because it has less brightness ? But it offers better color quality, with more contrast ? Is this analysis correct ?

Also, not sure what "*1*2" means, and why they wrote (max). Probably it provides less brightness on average.

On that particular specification page the *1 and *2 mean look further down the page at notes 1 and 2, which are as follows:

*1: Varies depending on conditions

*2: All brand names and product names are trademarks, registered trademarks or trade names of their respective holders. Lamp life specification is an estimate based on verification under proper conditions and is not the duration of the warranty. Lamp will shut-off automatically when usage reaches the specified estimated maximum lamp hours. Service life may vary widely depending on usage and operating environment and conditions, as well as users' adherence to the maintenance and cleaning procedures provided in the user manual.

In terms of which one is best - it will depend on your needs, but the second one has higher frame rate and better contrast, which for most applications will be what you need, however if you do need the extra brightness for displaying in brighter environments, the first one may be more appropriate for you.


Getting a model to hit same exact mark I am trying to see if there's a term for what I'm about to explain or a better way of doing this.  Basically, my company is filming an actor from the waist up for short, 1 or 2 sentence clips.  These clips need to be strung together to look as seamless as possible.

The main problem is that the model has to rely on muscle memory to remember where her head (specifically eyes, nose, mouth) and shoulders are in the frame.

My solution would be to use a mirror with a hole cut out for a camera lens.  On the mirror would be marks showing where her features should return to after she says something.

Is this typical, or is there a better way to do this? Or possibly to have another monitor with an overlay of the original position on it?

I'd just like to try to make sure she doesn't constantly look away from the camera to achieve this.

Any thoughts?

One option, if you don't mind the actor keeping her head still, is to be partially lying down. She could be in a recliner, leaning back, with her head against the headrest so she never moves it.  She would feel the headrest behind her so she could tell if she'd turned her head, and it wouldn't "drift" left or right because the friction of the headrest would keep it in place.

Of course you would want to shoot all her lines in as short a session as possible so she didn't get uncomfortable - like 5 minutes for all the lines and retakes.


FFMpeg - why recording a video and then compressing it produces a smaller size video than recording with combined options I played a recorded video to test this, so video content would be same in both cases.

Recorded video length is 1 Minute in both cases.

There may be a split second difference in the videos as I start FFMpeg command in cmd window and then switch to VLC player to playback video.

1) command to record:

ffmpeg -f gdigrab -framerate 30 -i desktop -f segment -segment_time 60 out12Dec1%03d.flv

This recorded video of 1 min is 9.99 MB.

2) command to compress:

ffmpeg -i out12Dec1000.flv -vcodec libx264 -crf 20 output.mp4

This compresses the video to 1.76 MB

3) Now I am trying to use the parameters to directly capture in compressed mode instead of using 2 steps.

ffmpeg -f gdigrab -framerate 30 -i desktop -f segment -segment_time 60 -vcodec libx264 -crf 20  outvcodec12Dec19%03d.mp4

I tried both with and without framerate option, and used flv / mp4 for output.
The output videos are between 2.24 to 2.57 MB.

Why is the recorded output in case 3 not close to 1.76 MB?

Your first command is transcoding using FLV1 codec to store in .flv. This is not the same input provided to the x264 encoder as when directly encoded to H264. In fact, it's quite worse, since the default target bitrate set for FLV1 is 200 kbps (although for full desktop capture, it will overshoot by a lot). This has less complex detail in general so it's easier for x264 to encode than the full fidelity raw desktop input.


Is there any method to create an audio visualizer as seen in video below So I've been looking for a certain effect to add to videos for my channel, and in doing so I can safely say that the internet is filled with useless and endless templates for simple audio visualizations or ungodly expensive suites that can't do what I actually want to do. (or at least similar)

There are three videos below, I believe them to have been rendered in After Effects.

this one is why I know it to be After Effects,

The uploader says to have been using javascript math expressions, alas I can not find anything where I could learn how to do anything close to that. Particles or no particles.  I'm more looking at trying to find something I can learn from rather than "can someone do this."  If there is any free resources out there I could possibly use?

The channel I linked has long been abandoned.

Edit: I can't even add the tags to this post of "Particles" or "Visualizer"

Audio Spectrum effect that comes with After Effects. Just apply the effect to a solid layer and there will be a dropdown of the layers in the current composition, select the audio layer.


ffmpeg - one input, two outputs - separate instances I've been struggling with a ffmpeg-related issue for a few days now.
What I am trying to accomplish is to grab AV signal from a single input (/dev/video0), then save it into two files simultaneously.

Output no. 1: raw AVI file, for further editing
Output no. 2: preview mp4 file, to work as a preview within an embedded VideoJS player on an webapp.

Here's my command:
ffmpeg -f v4l2 -standard PAL -i /dev/video0 -f alsa -thread_queue_size 512 -i hw:0,0 -preset superfast -crf 25 -r 25 -aspect 4:3 -acodec libmp3lame -b:v 6M -b:a 128k -channels 2 -ar 48000 /vids/vid1.avi | -acodec libmp3lame  -b:v 500k -b:a 128k -channels 2 -ar 48000 -y /opt/lampp/htdocs/preview.mp4

The command above doesn't seem to work for me. Where have I gone wrong?

Remove the pipe character.
ffmpeg -f v4l2 -standard PAL -i /dev/video0 -f alsa -thread_queue_size 512 -i hw:0,0 -preset superfast -crf 25 -r 25 -aspect 4:3 -acodec libmp3lame -b:v 6M -b:a 128k -ac 2 -ar 48000 /vids/vid1.avi -b:v 500k -b:a 128k -ac 2 -ar 48000 -y /opt/lampp/htdocs/preview.mp4
(mp3 is not standard in MP4 so let ffmpeg pick the default audio codec)


How to encode video to profile high using ffmpeg? This is my first post here. I am in a situation where my original file is of profile High and transcoding profile is High10. I am suspecting that this is the cause my video is not getting played in jwplayer. I have also tried to set profile to -profile:v high
but no help . I am using ffmpeg version

ffmpeg version 2.6.2

No pixel format specified, yuv420p10le for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
x264 [error]: high profile doesn't support a bit depth of 10
[libx264 @ 0x350d960] Error setting profile high.
[libx264 @ 0x350d960] Possible profiles: baseline main high high10 high422 high444

Please help me.

The ffmpeg build you have uses libx264 compiled for 10-bit. Apparently one can only build with support for either 8-bit OR 10-bit. So, you'll need a build where libx264 supports 8-bit.


avconv converting videos in really bad quality I have this linux command line app called avcon. It is used to converting files. For instance if I have a file called video.mp4 I can run avconv -i video.mp4 video.ogg and it will convert this video.mp4 to video.ogg.

So my problem(question):
Whenever it converts any file the output file's quality is super bad compared to the original video (the input video). How can I get around with that? I mean how can I convert the file and still get the same quality?

If this is not possible using this app. Can anybody suggest anything else for converting video files using the command line?

Get ffmpeg

Download a recent build of ffmpeg. Binaries for Windows, Linux, and OS X are available on the FFmpeg Download page. Development is very active and there is no need to use buggy avconv (note that this answer was written for ffmpeg, so I'm not sure if any examples will work with avconv).

Theora video & Vorbis audio in OGG

Theora is old and has been superseded in many cases by VP8/VP9 video in WebM (see example below), so there are few reasons to use Theora in OGG/OGV.

ffmpeg -i input -c:v libtheora -q:v 5 -c:a libvorbis -q:a 5 output.ogv

-q:v – video quality. Range is 0-10, where 10 is highest quality. 5-7 is a good range to try. If you omit -q:v then ffmpeg will use the default of -b:v 200k which will most likely provide a poor quality output, and libtheora may drop/skip frames if the bitrate is too low.
-q:a – audio quality. Range is 0-10, where 10 is highest quality. 3-6 is a good range to try. Default is -q:a 3.

Adapted from FFmpeg Wiki: A Brief Theora and Vorbis Encoding Guide.

VP8 video & Vorbis audio in WebM

ffmpeg -i input -c:v libvpx -qmin 0 -qmax 50 -crf 5 -b:v 1M -c:a libvorbis -q:a 5 output.webm

See FFmpeg Wiki: VP8 Encoding Guide and VP8 Encode Parameter Guide to optimize your command.
If you want to encode VP9 video, then use -c:v libvpx-vp9. It is currently a slow encoder.


QoS for video streaming What are the most used metrics to evaluate the QoS of a video streaming session? I am looking for tutorials, papers, lecture notes, ppt, anything of that kind, or your own answer.

From the perceptual front (in the user point of view):

Quality:
Here we are evaluating quality of video and audio being streamed. Usually, higher the bit rate better the quality - but it also means more cost. The basic quality measure for Video is PSNR. However, more relevant matrices from the perceptual quality is blockiness and there are many other approaches like this.
Usually, choosing the codec and bit rate fixes the quality primarily, so network doesn't effect that much in that case.
Consistency (or lack of jerkiness):
This is a rough measure of times when the continually running stream got interrupted. Usually this is a measure of length and pauses that are caused due to unavailability or reduction of bandwidth during some time and player needs to wait for the data to arrive.
Usually, buffering is done to the optimal level in the receiver to minimize the effect on this.
Errors in pictures:
This is the indication of errors occurred during the transmission due to which patchy or blank screens. There are cases, where transmission could be error free, in which case, this won't be a problem.
Latency:
This refer to amount of time the service needs to begin the deliver and time the system gets reflected to screen. There are various elements of the system that contributes to this. Usually, for VoD type systems, some reasonable but it is a reasonable concern for the two systems.
End-to-end delay or so called guarantee:
The end-to-end delay is essentially same as round trip delay between two systems. For two way communications like telephony, end-to-end delay is of great importance.
Service guarantee:
Usually, this refers to probability with which the given service will be surely available to the end users. This is equivalent to probability of call drops or network blocking of calls.

Intrinsic parameters:
Here we can think of QoS metrics from the point of view of basic measures of the network which is reflects the QoS as perceived by user.

Bit rate guarantees:
This includes the maximum and minimum of available bandwidth during the entire session. Guarantees available for the network bandwidth is usually the single most
Error rate or Loss runs:
Usually, unlike satellite paths, in the internet there are no bit errors (above transport layer) - the errors get reflected in the form of packet losses. Basic metrics is hence packet error rate on the networks. More research has concluded that these can be modeled as loss lengths where typically, errors occur in some bursts. The packet loss and the length of the losses has a significant effect in terms of perceptions. This paper describes this metric in depth.
Latencies or Various delays:
This involves the delay between the path, setup delay, resource reservation delays and buffer delay that all contributes to initialization of display and latency. Many a times, efficient codecs collects various pictures together before encoding to optimize bit rates this allows more efficient compression (higher quality) but increases the latency.
System uptime and usage factor:
If either the systems is dysfunctional (down) or it is fully utilized (blocked) it will have

The paper below shows good relationship between various taxonomies.
Survey of QoS specifications : http://eia.udg.es/~marzo/doctorat/aur98.pdf


Good codec for embedded system video decoding I need to get streaming video working where a source streams video to an embedded platform. This embedded system has an ARM-Cortex-A9 without a GPU or a hardware video decoder.

Unfortunately I don't have control over this platform so I will have to make do with what I have. I need to be able to decode live video with a maximum size of 640x480. I really have no clue what codec is best suited for this job. Bandwidth is less of an issue since it will run on the same network with a cable.

Does anyone have a recommendation of a codec that would be suitable in this situation?

While I haven't implemented this myself I would suspect Google's VP9 (or VP10) to be a good option.

Considering Android phones use an ARM CPU, the codecs and libraries supporting it should be highly optimized as they've been around for almost 10 years, and Google has a reason to continue improving it.  Plus it's royalty free both to play and to encode.

See VP9 on Wikipedia.


reasons for After Effects CC deprecating wmv and H.264 I've recently upgraded to After Effects CC from CS6 and I discovered that in the render queue, options for wmv and H.264 have been deprecated.  I know codecs come and go, but I'd like to understand the reasons why Adobe eliminated these options.  I know they're still available in Media Encoder CC, but why not After Effects CC?

While I'm not aware of any release of the official reasons for this, I can offer a strong theory based on my knowledge of the way workflows are intended with After Effects.  After Effects is an effects and composition package, it is not designed to be placed at the end of a processing pipeline, but rather in the middle of it.

After Effects is designed to work on clips that will be edited in to a finished product.  As such, it doesn't make a lot of sense to export from After Effects in a format that is targeted at end viewers, such as h.264 or WMV.  It makes much more sense to target high quality, low compression intermediate formats that will minimize iterative quality loss or simply to use embedded compositions directly in Premiere.

Since it isn't a designed use case to be doing final output from After Effects, it doesn't make a lot of sense to put in extra development time maintaining a feature that is redundant and not part of the main intended work flow of the product.  If you want to do a final output in that format, you can still use Media Encoder to do it and then they only have to license and maintain the encoders for one application rather than two.

It is unfortunate in the cases where you wanted to do a one off render of a clip, but that isn't their main use case that they are designing around.  They probably decided that maintaining that use case simply wasn't worth the cost of maintaining.


How to Stabilize Hyperlapse Footage Like GoPro Hypersmooth? How would you stabilise footage in post to the smoothness level of GoPro Hypersmooth automatically?

From what I have seen from online videos, the videos are way more stable than warp stabilised hyperlapses. I have also noticed that the faster (longer) the GoPro footage, the more stable it is. I suspect that they are selecting the best frames to put in the video and then run another round of electronic stabilisation. If I am not mistaken, warp stabiliser uses every single frame and warps them and thus will never be able to reach the GoPro stability of skipping unwanted frames.

Is there any way to do this automatically or semi-automatically? If GoPro can do it in a small package in seconds, it should be achievable in a powerful computer rig.

This is not only useful for handheld footage, but also gimbal/steadicam footage.

These use a combination of sensory input to counteract movement and crop the video so it resides inside of a larger one allowing it to move around and remove movement. It's a software based gimbal. I'm not sure if there is any plugins for AE or similar yet to achieve such effects. As most software is closed source that does this.


How can I record audio & video synced with another audio file? I want to record a drum cover. I have three input sources: a camera, the output of my electronic drum kit (computer registers it as a microphone), and an existing audio file (the song). I want to record myself playing along with the song, and have the resulting audio&video sync up exactly as I was playing it. I'm thinking I want to have a program where I import the song and put it as an audio track, then the program lets me record audio & video while playing back the existing project (namely the audio track).

What's a relatively cheap program that would allow me to do the above? As it is now I have to record the audio & video while I'm listening to the song, then edit the song file in a program to manually sync it with what I recorded, then import that modified song file into the program, which is too much of a pain.

You are over thinking it.  Edit a quick beep in before the audio starts on the song, play the song aloud while you are recording the drums.  Hit one of your drums so that you can see and hear it quickly on the video as well.  Record the audio direct from your drums and have a third track that is the microphone for the camera.  The camera audio track will here both the drums and see the drum hit being used to sync.  Then align the song and the drum track based on those markers in the video editor of your choice.


How can I make a video such that the quality degrades if someone tries to record it using screen recording software? How can I make a video such that the quality degrades if someone tries to record it using cam-studio or similar software? We create music videos which are often subjected to piracy. Although the CDs are encrypted, making it difficult for people to duplicate, anyone can record the videos using camstudio or similar software while playing it on their computer.

Rovi does try to add an element of security but the simple truth is that once it is being played, there is actually nothing you can do to prevent it being copied. Unless you control everything (including the screen) then an attacker can just wait until the encryption has been removed and copy the output. So this could be in memory, on screen, by intercepting HDMI etc.

This has been discussed at great length on security.stackexchange.com as it is one of the unsolved issues in security.


Equipment for video recording in a florescent lighted classroom What economy equipment is needed to record an educational event being presented in a classroom under florescent lighting with no exterior windows?

I am envisioning two hd-camcorders, each tripod mounted with one pointed at the podium and the other at the projected screen where supporting presentations may be shown.  I hope to capture two streams of the event simultaneously so that I can switch between speaker and stream during post-production.  I am also considering capturing a separate audio track using a digital voice recorder sitting on the podium.

I'm more interested in the clarity of the captured image than the color balance under florescence.  The screen contents may include small text that should be readable in the final HD video.  My only other consideration is that the camcorders have removable batteries and recording media (sdram, etc.) so that I can record multiple one hour events during the course of the day.

I have done this with cheap camcorders and they work great! Currently, I use a Sony camcorder, and a Panasonic, and the only major difference is the brightness of the screen, which only bothers me outside in full sun. However, you are not going to be happy with footage of a presentation screen. There will be moire effects and other problems, and you are way better off getting a digital copy of the presentation PowerPoint or photos or whatever they are using, then editing those originals into your video.

In my experience doing this though, many speakers are incredibly boring to watch, and audio of what was said is way more important than video of the talking head. Your video cameras won't capture production-quality audio, but you can capture that separately by patching into the PA system. You'll obviously need to coordinate with the sound guy for that. They may be able to just give a recording, or you might need to bring your own equipment. ASK first, because some sound guys really don't like you messing with their equipment, and some are happy to hand you a patch cable.

Also, sounds like you're planning to do this for a conference? Many conferences already do very good quality recordings. Unless you're the guy doing that, you might ask about that - I prefer not to make videos when I can buy them :)

I am reluctant to suggest specific equipment because it will be out of date as soon as I submit my answer. I can confirm that many cheap camcorders do fine with business presentations, but I'm reluctant to suggest any specific models. Just look for the removable memory and batteries feature and get whatever seems like a good deal. Sony and Panasonic both have excellent imaging quality, but I prefer the Sony (it is one year newer which is probably the only difference).

Here's two pretty lousy examples:

             - A presentation about 2.4GHz radio control systems.

             - John Penny speaks about piloting the Rare Bear Reno Racer plane.

This is what you can acheive with cheap camcorders and no setup at all. If you have time to do setup, you could improve on this, but as you can see, video of the screen and the speaker aren't going to work together. I have also done video recording at a conference, but those are private. It came out better because I only recorded the speaker, and I had access to all the PowerPoint slides, which we edited into the video later at full quality. If you plan to do that, get a really smooth tripod and follow the speaker, or ask them to stay within your frame. Some speakers are really animated and they cover the entire front of the room walking around. That's going to be a problem for fixed shots. Tape on the ground can help the speakers stay in frame.


How to split video output signal from 1 PC to 40 projectors? I am thinking of implementing this by daisy-chaining multiple splitters but I am not sure if it will work.

Does anyone know of a cost-effective solution to this?

Thanks.

You can't use a passive splitter for this as the signal level would drop far too low, however it should be trivial to accomplish with some simple active distribution amplifiers.

There are two real solutions for this and the best bet really depends on the details of where the projectors are.  More than just splitting the signal, the amount of distance to the projectors may also be an issue as most video signals degrade over long distance cable runs.

If all the runs are fairly short or you are able to use either fiber or signal boosters, you can use a large distribution amplifier or matrix switch to feed one signal to all 40 outputs at one location.

Alternately, you could use a series of smaller distribution amplifiers to spider out from the middle.  As each DA will also act as a repeater, it should help you cover a longer distance and you only need a chain of about 3 to cover all 40 projectors if you are using 4 way DAs.  You'd start with the signal in the middle, run it in to a distribution amplifier and run each of the 4 outputs in to another distribution amplifier heading off towards your other projectors.  Those 4 DAs would give you 16 total outputs.  Each one of those would run in to another 4 way DA and give you a total of up to 64 outputs, which easily covers your 40 projectors.

Another option if exact timing doesn't matter and you already have a solid Ethernet network in place would be to stream the video over the network and have each projector play back the stream independently.

A final option would be to setup a short range broadcast using wireless gear, however this is probably the most costly and potentially most error prone of the options though it can also be the easiest to setup if the environment supports it as it doesn't require multiple splitters or any complicated wiring, however transmitters tend to not be cheap as the range gets longer and beyond a certain range, you start needing licenses.


Zoom in/out transition in Blender Does anyone know hot to create this zoom transition in Blender? I don't know how to create directional blur.

Directional Blur is a feature of the VSE (video sequence editor), aka compositor.  When you open up Blender, select Video Editing as the Screen Layout.  Make one window a Node Editor (where you will introduce your directional blur node), and choose the Compositing view. Open another window as a Video Sequence Editor (where you will put your clips) and view it as a Sequence.  Then, either enable Backdrop in the Node Editor (so you can see your rendered result) or open a third window as a UV/Image Editor displaying Rendered Result.  You might have to set your render resolution to get 100% of your image (because the default is to render at 50% resolution, and while that just shrinks things for 3D worlds, it crops things for the compositor).

At the first frame, set the number of iterations to 1 and set a keyframe (right click).  Set the zoom factor to 0 and set a keyframe.  At the last frame, set the zoom to 1.0 or 2.0 or whatever you consider to be a maximum.  Tune up the number of iterations to whatever makes it smooth (could be 10, 20, whatever).  Keyframe those.

With your second clip (that you are zooming to), set the first frame of the effect to the same zoom and iteration numbers that you used for the last frame of your first clip.  Keyframe those.  For the last frame of the effect, set the iteration count to 1 and the zoom amount to 0.0 and keyframe those.  Then cross fade between the two.

In the middle you should have two very zoomed images that, when blended 50/50, look like they could logically belong to either image (because it's mostly just blurred pixels).

The above was checked with the latest release of Blender: 2.79b.


Automatic motion blur in video editor? Is there an alternative to the automatic motion blur in After Effects for Adobe Premiere, Sony Vegas or Final Cut?

I use it mainly to sync text/image animations with sound cues, however After Effects is not a real-time editor and is difficult to work with several layers.

Is this possible?

Motion from Apple has a setting for Motion Blur on all projects. This section of the documentation explains how to set it (in the project settings). (It's under "Motion Blur and Reflection Settings".)

Once the project setting is set, you may also need to turn it on in the canvas to see it while editing. See here for information on turning it on in the Canvas. (It's under the section named "Render pop-up menu.")

Motion renders a lot of stuff in real time, though turning on Motion Blur will slow it down. You can always set the number of samples to something low-ish (like 4 or 8) while working and turn it up for renders.

I believe that if you're using a Motion template in FCP that it will render the Motion Blur if you set the canvas to "Better Quality" playback.


Create Alpha channel-Videos (obs stinger compatible) with ffmpeg and 2 files I have 2 video files. One file is the main content and the other file has an alpha channel emulated with black and white (white = opacity 100 and black = opacity 0). Sometimes the emulated alpha channel file has only full black and full white frames, but I think some videos that I want to create will have complex alpha channel emulation with gray scales.

Is it possible to make with ffmpeg an vp8,vp9 -pix_fmt yuva420p ready .webm movie?

The alphaextract/alphamerge filters are meant for this.

Since your alpha reference is already greyscale, we only need the alphamerge filter

ffmpeg -i main.mp4 -i alpha.mp4 -filter_complex [0][1]alphamerge,format=yuva420p -c:v libvpx -auto-alt-ref 0 out.webm


Is there a way to record my handwriting and/or drawing as a transparent video in motion? I would prefer to achieve this with my iPad, but I also have an iMac if necessary.

What I want is to record my own handwriting and put the resulting video in real time on top of another video. An app called Video Brush does this (by writing directly on the video), but the footage it exports is unusable due to being jumpy, like it had export issues. Another app called Write-on Video gets close, but the writing just appears. It doesn’t show the writing in motion.

There are a few apps that allow me to achieve this on a white background (VideoScribe, Adobe Sketch recording the screen, etc..)

TLDR; is there any way for me to either write directly on a video and make that writing part of the video or to write/draw on video with a transparent background?

I found a solution, beit a bit ineligant. I screen-record myself drawing in white on a green background using Adobe Sketch. Then use Filmaker Pro’s green screen feature to put in a different background.

Still let me know if you guys have any other ideas.


Adobe Premiere & Final Cut Pro project file standard? Is there a standard for non-linear video project files? I want to create a slideshow of my life using jpg + mp3 files and want to be able to tweak it many years from now. My fear is that if I use Adobe Premiere, it will not be easy to migrate to Final Cut Pro or vice versa or whatever file format is used in the industry standard application in the future.

It's not like having txt files which you can be reasonably sure will still be editable 20 years from now.

FCP can export an XML file that contains the basics of your sequence. Premiere can then import this and create a native project file based on the contents of that XML. I'm pretty sure Premiere can also export a similar file for import/conversion into FCP (I haven't tried though).

It's worth noting that the formats are likely to change considerably years down the line, to the extent that a later version of the same software package may not be able to open it. You're best bet is to make sure all the individual files are archived so that if you're in that situation, you can just start over with the same files.


How do I crop out Region of Interest (ROI) from .mp4 video using FFMPEG? I would like to crop out ROI from specific .mp4 file. User needs to define the ROI by specifying X,Y,Width and Height in percentage between 0 and 10000.

For example, if someone specifies X=4000, and Y=3000 that would mean that top left corner (starting point of the crop) is located 40% to the right from bottom left corner of the video, and 30% down from top left corner of the video. Width and Height should determine bottom right and top left corners.

I am currently doing some tests on this image:

I expected following command to crop out 50% of the width and 50% of the height of the image, starting from top left corner:

ffmpeg -i test.png -filter:v "crop=in_w*(5000/10000):in_h*(5000/10000):in_w:in_h" -c:a copy roi.png

For some reason I get bottom right quarter instead of top left quarter of the image. What am I doing wrong?

EDIT

Once I change command to:

 ffmpeg -i test.png -filter:v "crop=in_w*(5000/10000):in_h*(5000/10000):0:in_h" -c:a copy roi.png

I get top right quarter of the image:

Since I specified X=in_w, and Y=0, this means that (X,Y) is top-right corner of the image. If that is true, and W is 50% of in_w, while H is also 50% of in_h, and I specified (X,Y) to be at top right corner, how did FFMPEG decide that it needs to go to the LEFT of the (X,Y) coordinate and not to the RIGHT in order to make the crop?

Because if it went to the right like it normally does, it would go out of range I guess. How is this logic implemented? I would like to know so I know how to program edge cases for it.

The crop filter arguments specify a crop window of the given width and height whose top-left corner is at co-ordinates (x, y) measured from top-left corner of the input frame. The entire crop window must be contained within the frame. So, to start with, w <= iw && h <= ih.

Then, x+w <= iw && x >= 0 and y+h <= ih && y >= 0. If this condition isn't meant, x or y will be adjusted to auto-center the crop window along that axis, e.g. for a 100x100 input, if w = 50 and x = 60, then x is adjusted to (100-50)/2 = 25.


how to convert mp4 to divx? I have the following DVD player - http://www.lg.com/ae/video/lg-DP542 -
and I want to convert my mp4 files into DivX as that is what my player supports. I tried VLC's converter and Handshake but had no luck. Can you help?

The good old ffmpeg gives you the power ;)

ffmpeg -i input.avi -c:v libxvid output.avi

You can obviously fine tweak the command line with bitrate, audio in mp3 and so on.

es:

ffmpeg -i input.avi -c:v libxvid -b:v 512k -c:a libmp3lame -qscale:a 4 output.avi

This is for a single bitrate use, where you use a constant bitrate for every frame.

Otherwise you could go for a 2 pass bitrate where the 1st pass is used only for determine where is the best for allocate more data...

But you can also convert in xvid/divx Mpeg 4 Layer 2 using a quality preset where you don't put directly the bitrate wanted but just ask for a minimum visual quality respected where you will be less concerned about the final file size (it will be discovered only at the end).

-qscale:v 3 instead of the -b:v 512k that i used above


How to render videos with placeholders using API / command line interface? I would like to be able to automate video creation and rendering.

I imagine the process as creating placeholders, which then can take my dynamic input (images/videos/text).

I would like to know the process of creating videos with placeholders as https://placeit.net/instagram-story-video-template here. Clearly, the video contains a placeholder for the text that we specify. How is this done on the low level?

None of the softwares for video rendering e.g. Final cut Pro etc. can be run on a server using CLI (command line interface).

Which backend / libraries can be used to create something like that?

You could write a simple shell script (either for mac or windows) which consists of basic if - then clauses to read the input of the user, then use ffmpeg by calling it from within the script. I believe that ffmpeg might be the most painless option, since scripting for Premiere and After Effects can be a bit tedious.


Speeding Up, Joining and Increasing Frame Rate FFMPEG "Is it possible to speed up a video using handbrake?"

In the above link, Mulvya show us how to speed up a video, but I want to know, if possible, how can I speed the video joining two or more videos and increasing the frame rate, for example:

I have 2 video files, which I need to join. Both are at 30fps and I want to speed up to 5 times and increase the frame rate to 60fps.

How can I do it?

Assuming audio's not a concern,

ffmpeg -i in1.mov -i in2.mov -filter_complex
       "[0]setpts=(PTS-STARTPTS)/5[a];[1]setpts=(PTS-STARTPTS)/5[b];[a][b]concat[v]"
       -map "[v]" -r 60 -crf 18 output.mov


ffmpeg colormatrix operations only for 8bpc? Unless I'm bad at reading, this page states that colormatrix is only good for 8 bpc.

From Colorspace support in FFmpeg:

  ... colormatrix produces horrible quality for anything > 8bpc (8-bit per component)

Backstory.  One of my typical workflows is to convert 16bit tiffs and 10bit DPX frames into 10bit prores.  However, I think the input colorspace of the frames is assumed to be bt601 and I would always get encodes that looks just slightly off from my originals.  I solved this by adding:

-vf colormatrix=bt601:bt709

And it looks fine visually.  The difference between the source and encode I always just assumed was the lossy compression.

So can someone chime in on if the colormatrix=bt601:bt709 operation is 'supposed' to be bad when the source and encode are >10bpc?  Or is the info on that page outdated?  Or should I be doing it a different way?

Yes, as it says a couple of lines above, colormatrix supports only 8bpc (8-bit per component) pixel formats. So, when a 16-bit input is filtered with colormatrix, it will be converted to 8-bits. And won't get converted back to 16-bit unless manually done or auto-converted due to output encoder limitations. But that's pointless anyway, as the precision has been lost.

Use the colorspace filter.

-vf colorspace=all=bt709:range=tv:format=yuv422p10:iall=bt601:irange=tv

Depending on your use case, format may need to be yuv444p10. Depending in your input, irange may need to be pc.


Slowing down footage with easing (like iPhone 5s) I have a 120 fps footage captured with a GoPro that I'd like to slow down with easing, like the slow motion playback functionality on iPhone 5s.

Is that possible without any extra plugins in Final Cut Pro X? I know how to slow down a footage, but I'd really like the effect from normal speed to slow motion.

You can do it by adding transitions between the speed changed clips as described in the documentation section titled Add Transitions Between Speed Segments. They say:

  When two adjacent speed segments are set to play at different speeds, you can control how smoothly the video switches between the playback speeds. When there’s no transition between the segments, playback shifts suddenly from one speed to another. By adding a transition between the segments, you can create a more gradual, or ramped, effect. You can also control how quickly that transition takes place.


How to paste one specific attribute only? "Paste attributes" allows me to select which effects I want to paste.

However, for "Motion", it seems to be all or nothing (screenshot below). This is even though within "Motion" itself, there are 5 separate attributes, namely, Position, Scale, Rotation, Anchor Point, and Anti-flicker Filter.

What if I only want to paste, say, the Scale of one clip on 10 other clips, without changing the Position, Rotation, Anchor Point, or Anti-flicker Filter of the other 10 clips?

(Using CC 2015.)

There is no simple way to do this, as Position, Scale, Rotation, Anchor Point, and Anti-flicker Filter are attributes of the Motion effect that is applied to all clips by default. So even though the Paste Attributes panel allows you to paste effects individually, you can't paste the individual attibutes of the Motion effect.

You can, however, use a workaround.

In this case, a simple solution is to add a keyframe and copy that instead. If you have only one keyframe per attribute that holds the desired value, it won't change over time, thus it will be the same as not having the keyframe at all and just using a static value for that attribute.

Step by step:

Select a clip in the timeline and in the Effect Settings panel, set a value for the attribute you want to change (e.g. Scale).
Now press the Toggle Animation button (the clock icon next to the effect attribute designation). This will add one keyframe at the current playhead position that holds the value set in step one. If you want to change that value later on, make sure that the playhead is exactly on this keyframe, as it will create a new keyframe otherwise.
Select the keyframe by clicking on it and press CTRL + C to copy it into the clipboard.
Now select the target clip that you want to paste the attribute onto in the timeline and switch to the Effect Settings panel once more. Press CTRL + V to paste the keyframe. The keyframe still holds the value set in step 1., so you have effectively pasted just that attribute's value onto the new clip.

You can also do this with multiple keyframes (both within one attribute, in case you do want to change the attribute's values over time, or spanning multiple attributes). Just marquee select all the keyframes and copy them into the clipboard. The program will remember which attribute each keyframe belongs to. If you paste multiple keyframes with intervals between them, the intervals will remain and the first keyframe in the section will be pasted at the current playhead position.


Automated/Scripted Video Editing I am looking for a scripting language that can handle cutting together 50+ mp4 files.  In addition to this I'd also like it if I can provide a text file with the date of each video and make some sort of slightly opaque box containing the date that I can burn over the video.  Is there a good tool out there for this?  Most of the stuff I've found only works on avi files.

Consider the following technologies:

ffmpeg + command line
Adobe After Effects + ExtendScript language (based on JavaScript)
Sony Vegas Pro + C# language (or any other Microsoft .NET language)


Audio recording: is/how a dedicated device better than laptop? I'm about to make a series of tutorial videos, but my experience with sound recording is next to zero.

After watching quite a few videos on sound recording, gear reviews and other usual stuff, there's one particular point I'm still not quite getting: is there any advantage of using an external recorder as opposed to sticking a decent lavaliere microphone into my laptop and record with using Audacity (or some other software)?

The initial plan is rather humble: talking head recorded with a modern smartphone camera plus screencasts, everything to be shot indoors, so portability of sound recording device is not an issue. The question is, should I then just focus on choosing a microphone, or is there any advantage in using a dedicated device in terms of sound quality?

There's no quality difference to where the recording is stored - if you plug the same mic into different recording devices, it should record the same. Different quality mics (and recording environment) will give you more difference to your sound than anything else. Do make sure you are recording uncompressed (WAV) format though, using compressed formats will obviously reduce your resulting audio quality.

I have some external recorders, I use them mainly because you can plug in a large SD card, hit record, and the device will just sit there and do that job for hours, no issue. I don't have to worry about a piece of software or laptop crashing, they're portable and I can plug them in at the back of a sound desk or anywhere I like, etc. If you're recording lots of audio, they're just handy to have and use. Most external recorders do default to higher quality settings than what Audacity might (i.e. mine default to 24-bit/96kHz), but you can change those settings in Audacity as required. Portable recorders can also have other interfaces and features that come in handy if you're using them in lots of different environments - I almost always just use mine with the same standard setup, and most of the extras go unused!

For what you're doing, hooking the mic into a laptop and using Audacity will do the same job just fine. Just make sure to monitor things and check your recordings - make sure audio isn't being dropped due to inability of the system to keep up to speed, and that everything is recording as you expect (mic cable/connection good, levels good, mic close enough to the source to pick up the sound cleanly, etc).

You might also consider adaptors for your phone:
https://www.rode.com/microphones/sc6-lik

I've not personally used these, but there are various adaptors out there now to interface sound inputs direct to your phone, as well as dedicated external mics (the above adaptor gives you a more generic approach that you could plug anything into, but there are specific mic only devices for phones as well). I would just double check how the quality options would vary on a phone recording vs using Audacity dedicated on a laptop, which might not even matter for the types of recordings you are describing.


Retaining quality while re-encoding with same codec Just say I have a bunch of separate clips (DV stream format .dv), and I join them using Quicktime 7. If I then export them out as a new .dv file, am I losing any quality?

Is there a loss in quality if you re-encode a video under the same exact codec with the same exact settings? If so, how can I join my clips and retain the original quality?

It can depend on the compression used, but generally yes, there will be a loss of quality, particularly if there is any alteration to the video.  For a fairly low compression format like DV it probably isn't going to be much, but the best bet, if the format supports it, is to append the stream data and alter the file such that it has the necessary format or simply make a virtual clip if your editing environment supports it.

Personally, I've always taken the latter option when working with DV, so I don't recall if it is a format that easily supports combining files or not, though I would expect it is since it compresses every frame independently as I recall. (May be wrong on that though, haven't worked with DV in a while.)


Help with shooting steady I need help with learning how to shoot videos for real estate. My first problem is that I am not strong enough to manage the camera without it shaking or picking up my walking movements. I purchased the Glidecam Smooth shooter and I still can't get videos that are smooth. (ok, so I am a weakling). So that's my first problem... the 2nd is that I need to know from everyone else their suggestions for the best camera for the job. I am currently using Canon 5d Mark II. One of the biggest problems is that when I pass a window the exposure goes crazy and the focus gets blurry.

I know I'm asking a lot here, but ugh, help...

I never tried this myself, but I believe attaching a camera firmly to a tripod with wheels or putting the Glidecam Smooth Shooter onto a car or something sturdy with wheels might work for you.


Program that uses grayscale images to make transitions I remember some old video editing programs used a grayscale image to be used as a transition pattern.

Basically what they did was using the different levels of a grayscale image as a step for the transition.

Here is an example. Given the first image, when the program was analyzing the gray level marked with the red line as a threshold, the transition would look like the image below.

Do you know if that can be done in a free program like Davinci Resolve, Hit Film, probably Blender?

And a tip of how can be implemented?

images by pixabay

What you want is called a Gradient Wipe in Premiere Pro or a Luma Fade in Davinci Resolve.

Just make sure your gradient image is a 3rd layer as long as your transition, and is selected as the 'gradient layer.'

(This should be a comment but I don't have enough karma to comment in this forum. Hope this helps :) )


Shutter speed when recording with DSLR I know that the shutter speed should be approximatively as twice as much the fps. However, I know people who tune the shutter speed to any value they need it to achieve the correct exposure. They say that, except for a few cases, using a shutter speed bigger than the recommended value (2X the fps) is not noticeable.

I would like to hear your opinion about this. It is quite important to me, because if this is true, I would avoid using ND filters, as they reduce image quality.

On DSLRs, a fast shutter can actually be better.  DSLRs scan the image to sample rather than capturing the whole frame at once.  This is why you get a distortion when you do a rapid pan.  A faster shutter will result in stopping motion more clearly (less motion blur), which can seem a little harsher than the softness of film, but a sharper image may be preferable.  That said, a good ND shouldn't have a significant impact on image quality.

So, my final advice is, if you want crisp frames with little motion blur, use high shutter speed, if you need smooth motion for things moving around a static scene, a high quality ND is probably better.  If you simply have a fairly static shot, then shutter is probably the way to go again.


Closed Caption formats - support for overlapping phrases I am looking to develop a tool for editing Closed Captions for MP3s.  It is mostly in support of YouTube music videos.  I've been looking over the Supported Caption File Formats in this YouTube page and the example they show is:

0:01:23.000,0:01:25.000
This text displays for two seconds starting
1 minute and 23 seconds into the video.

0:02:20.250,0:02:23.8
This text displays from 2 minutes and 20.25 seconds after the start
of the video until 2 minutes and 23.8 seconds after the start of the video.

0:03:14.159
This text displays beginning 3 minutes and 14.159 seconds
after the start of the video for an undefined length of time.

It seems clear enough there, with the first line being start,end time, the blank line being a delimiter, and the rest indicating text and line breaks.  The last 'time' entry indicates a start time but no explicit end time - it is up to the software to define how to render it (any examples my software makes, will have an explicit start & end time).  That is basically what is shown in the SubViewer (http:// en.wikipedia.org/wiki/SubViewer - link broken to reduce 3 links to maximum of 2) example at Wikipedia.

What neither page makes clear is whether the captions could effectively overlap.  E.G. a busy meeting, or songs with lead and back-up vocals.  An example of the latter is Johnny O'Keefe's - She's My Baby.

The BG vocals start

1. Bom, bom, bom, BOM..

Continue that with 2 & 3 (when you're on a good 'bom', roll with it..)

Then JO'K cuts in with ..

4a.                Short black hair..
4b. Bom, bom, bom, BOM..

Does the format specify/expect that all captions will be non-overlapping periods of time, like lines 1-3, or does it also support 'interleaved' text as with lines 4 a/b?

I tried this just a short while ago, and YouTube supports interleaving captions! You can even jumble the captions around in time. So the first caption could be the last one showing up in the video.

Just specify the starting time and the end time on all of the captions and they will show up during the time you specified.

Have a good time captioning! :)