question: Does streaming a YouTube video use the same amount of data regardless of whether it’s actually a moving image? For example, sometimes I just listen to a piece of music and the “video” is just a picture of the album cover. Does this use less data because it’s not a moving image?
comment: Oh man I hope I can explain well enough. Music with just an album cover image should use less data if it's a static image. Less refresh and painting of images on screen means less data is needed. Rewatching/listening to it immediately could potentially save a little data if it's cached and rewound in the browser window but if you refresh the page to reload it, it might use more data, but I'm not sure how YouTube handles that content in either instance. On a lot of YouTube apps, there's an option for "Stats for nerds" and it'll show you you real-time bandwidth usage.
passages: BULLET::::- Video streaming: , Netflix had 3.14 petabytes of video "master copies", which it compresses and converts into 100 different formats for streaming.
  
  BULLET::::- Photos: , Facebook users had uploaded over 240 billion photos, with 350 million new photos every day. For each uploaded photo, Facebook generates and stores four images of different sizes, which translated to a total of 960 billion images and an estimated 357 petabytes of storage.
  
  BULLET::::- Music: One petabyte of average MP3-encoded songs (for mobile, roughly one megabyte per minute), would require 2000 years to play.
   An industry that is impacted by data streaming is the Video Streaming industry. Consumers are now demanding videos to be available at immediate request, meaning that it is no longer only the quality resolution of image that acts as important performance metrics in the media industry, but also how quickly video starts to play.
   The performance of an algorithm that operates on data streams is measured by three basic factors:
  
  BULLET::::- The number of passes the algorithm must make over the stream.
  
  BULLET::::- The available memory.
  
  BULLET::::- The running time of the algorithm.
   The amount of data used by video streaming services depends on the quality of the video. Thus, Android Central breaks down how much data is used (on a smartphone) with regards to different video resolutions. According to their findings, per hour video between 240p and 320p resolution uses roughly 0.3GB. Standard video, which is clocked in at a resolution of 480p, uses approximately 0.7GB per hour. 
   BULLET::::- The scene frame is proposed by AVS2 based on the surveillance video coding method of background modeling. When the surveillance tool is not opened, Frame I is only for reference for images before the next random access point. When the surveillance tool is opened, AVS2 will apply a certain frame in the video as the scene image frame G, which can be considered as a long-term reference for the subsequent images.
  
  BULLET::::- AVS2 can generate the scene image frame GB with some frames in the video, and frame GB can also be applied as a long-term reference.
   YouTube accepts videos that are uploaded in most container formats, including AVI, MP4, MPEG-PS, QuickTime File Format and FLV. It supports WebM files and also 3GP, allowing videos to be uploaded from mobile phones.
  
  Videos with progressive scanning or interlaced scanning can be uploaded, but for the best video quality, YouTube suggests interlaced videos be deinterlaced before uploading. All the video formats on YouTube use progressive scanning. YouTube's statistics shows that interlaced videos are still being uploaded to YouTube, and there is no sign of that actually dwindling. YouTube attributes this to uploading of made-for-TV content.
  
  Section::::Features.:Video technology.:Quality and formats.
   The image change rate fundamentally affects how "fluid" the motion it captures will look on the screen. Moving image material, based on this, is sometimes divided into two groups: "film-based" material, where the image of the scene is captured by camera 24 times a second (24 Hz), and "video-based" material, where the image is captured roughly 50 or 60 times a second.
   BULLET::::- Alternative transfer characteristics information SEI message, provides information on the preferred transfer function to use. The primary use case for this would be to deliver HLG video in a way that would be backward compatible with legacy devices.
  
  BULLET::::- Ambient viewing environment SEI message, provides information on the ambient light of the viewing environment that was used to author the video.
  
  Section::::Profiles.
   In interlaced video, the horizontal scan lines of each complete frame are treated as if numbered consecutively, and captured as two "fields": an "odd field" (upper field) consisting of the odd-numbered lines and an "even field" (lower field) consisting of the even-numbered lines. Analog display devices reproduce each frame, effectively doubling the frame rate as far as perceptible overall flicker is concerned. When the image capture device acquires the fields one at a time, rather than dividing up a complete frame after it is captured, the frame rate for motion is effectively doubled as well, resulting in smoother, more lifelike reproduction of rapidly moving parts of the image when viewed on an interlaced CRT display.
   BULLET::::- Spatial (picture size) scalability: video is coded at multiple spatial resolutions. The data and decoded samples of lower resolutions can be used to predict data or samples of higher resolutions in order to reduce the bit rate to code the higher resolutions.
  
  BULLET::::- SNR/Quality/Fidelity scalability: video is coded at a single spatial resolution but at different qualities. The data and decoded samples of lower qualities can be used to predict data or samples of higher qualities in order to reduce the bit rate to code the higher qualities.
   BULLET::::- Motion estimation (ME) search strategy can also cause different visual quality for the same PSNR. So-called "true motion" search commonly will not reach minimum sum of absolute differences (SAD) values in codec ME, but may result in better visual quality. Such methods also require more compression time.
  
  BULLET::::- Rate control strategy. VBR commonly cause better visual quality marks than CBR for the same average PSNR values for sequences.
   In July 2018, Billboard and Nielsen revised the ratios used for streaming equivalent album units to account for the relative value of streams on paid music services like Apple Music or Amazon Music Unlimited versus ad-supported music and video platforms such as Spotify's free tier and YouTube. Under the updated album equivalent ratios, 1,250 premium audio streams, 3,750 ad-supported streams, or 3,750 video streams are equal to one album unit.
  
  Similarly the Recording Industry Association of America, which had previously certified albums based on units sold to retail stores, began factoring streaming for their certifications in February 2016.
   BULLET::::- Full Reference Methods (FR): FR models compute the quality difference by comparing the original video signal against the received video signal. Typically, every pixel from the source is compared against the corresponding pixel at the received video, with no knowledge about the encoding or transmission process in between. More elaborate algorithms may choose to combine the pixel-based estimation with other approaches such as described below. FR models are usually the most accurate at the expense of higher computational effort. As they require availability of the original video before transmission or coding, they cannot be used in all situations (e.g., where the quality is measured from a client device).
   While MPEG-2 allowed a ½ pixel resolution, Inter frame allows up to ¼ pixel resolution. That means that it is possible to search a block in the frame to be coded in other reference frames, or we can interpolate nonexistent pixels to find blocks that are even better suited to the current block. If motion vector is an integer number of units of samples, that means it is possible to find in reference pictures the compensated block in motion. If motion vector is not an integer, the prediction will be obtained from interpolated pixels by an interpolator filter to horizontal and vertical directions.
   BULLET::::2. The STREAM convention: sums the amount of data that the application code explicitly reads plus the amount of data that the application code explicitly writes. Using the previous 1 million byte copy example, the STREAM bandwidth would be counted as 1 million bytes read plus 1 million bytes written in one second, for a total of 2 million bytes per second. The STREAM convention is most directly tied to the user code, but may not count all the data traffic that the hardware is actually required to perform.
   To reduce data rate and hardware requirements, video frame has size of 960 horizontal by 540 vertical pixels with pixel aspect ratio of 1:1, which results in display aspect ratio. Progressive scanning at 30 or 25 frames per second reduces data rate even further, but may result in increased “judder” when compared to the traditional rate of 60 or 50 images per second (fields or complete frames depending on scanning type) used for television broadcast.
  
  As of 2013, Apple has not made detailed information about this recording format publicly available.
  
  Section::::Relation to other technologies.
   BULLET::::- the cost of the TV card can be lower because there is no need to supply an MPEG-2 encoder
  
  BULLET::::- the quality of captures can be higher because there is no need to re-encode streams
  
  BULLET::::- ratio of file size to quality is higher due to the broadcasters' high-efficiency encoders
   Streaming is a guaranteed delivery style of service. A terminal requests a context of X bandwidth (currently 8, 16, 32, 64, 128, or 256kbit/s) and, if the current spot beam has enough resources available, it is allocated a guaranteed chunk of the available bandwidth. So if it asks for an 8k streaming context, the terminal will at all times be able to send data at 8kbit/s.
  
  Streaming contexts are billed by time.
  
  Section::::Data services.:Background.
   BULLET::::- Reduced Reference Methods (RR): RR models extract some features of both videos and compare them to give a quality score. They are used when all the original video is not available, or when it would be practically impossible to do so, e.g. in a transmission with a limited bandwidth. This makes them more efficient than FR models at the expense of lower accuracy.
   Section::::Techniques.:Cloud.
  
  A newer approach is to perform video and multimedia optimization in "the cloud" – data centers either operated by the service provider or by a third party. The major benefits of this technique are that it allows smoother bit rate adaptation and utilizes transcoding and caching methods to distribute resources only when and where they are needed.
   Section::::See also.
  
  BULLET::::- UHDTV – digital television formats with resolutions of 4K / 2160p (3840×2160) and 8K / 4320p (7680×4320)
  
  BULLET::::- Rec. 2020 – ITU-R Recommendation for UHDTV with standard dynamic range
  
  BULLET::::- Rec. 2100 – ITU-R Recommendation for HDTV and UHDTV with high dynamic range
  
  BULLET::::- Image file formats based on HEVC
  
  BULLET::::- Better Portable Graphics – a file format for images based on HEVC
  
  BULLET::::- High Efficiency Image File Format – a file format for images and image sequences based on HEVC
  
  BULLET::::- Comparison of video codecs
  
  BULLET::::- List of open-source codecs
   Interlace introduces a potential problem called interline twitter, a form of moiré. This aliasing effect only shows up under certain circumstances—when the subject contains vertical detail that approaches the horizontal resolution of the video format. For instance, a finely striped jacket on a news anchor may produce a shimmering effect. This is "twittering". Television professionals avoid wearing clothing with fine striped patterns for this reason. Professional video cameras or computer-generated imagery systems apply a low-pass filter to the vertical resolution of the signal to prevent interline twitter.
   Video codecs such as MPEG-2, H.264 or Ogg Theora reduce the amount of data in a stream by following key frames with one or more inter frames. These frames can typically be encoded using a lower bit rate than is needed for key frames because much of the image is ordinarily similar, so only the changing parts need to be coded.
  
  Section::::See also.
  
  BULLET::::- Video compression picture types
  
  Section::::References.
  
  BULLET::::- Software H.264: http://iphome.hhi.de/suehring/tml/download/
   In order to increase the resolution of video images, therefore, new schemes have been created that capture full-frame images for each frame. Video composed of such frames is called progressive scan video.
   (3,600 s × 300,000 bit/s) / (8×1024×1024) requires around 128 MB of storage. 
  