Video Compression, Codecs, and Containers Explained When you get an email from Netflix that says, “Watch your favorite movies, now in 1080p H.264 format!” What does that even mean? Compression What it is? Data coding methods for controlling or limiting file size and total information contained in video files. While this is similar to codec, there are some characteristics unique to compression techniques that go beyond just codec. Why care? Every video file has gone through some kind of compression. For video files, the parameters that control compression are: Video codec, resolution, data rate, and (with older video files) scanning. Once a video has been compressed, it cannot be decompressed, compression is usually made possible by limiting the information that is collected, and so that information cannot be restored to a file once it has been compressed. Determining the compression, even with just a cursory understanding, can help you understand how the videol be can be used and what limitations it might have. In video production, all of these compression parameters can be manipulated in order to achieve specific goals. Just remember that your source footage needs to be less compressed or as compressed as your final video format. Commonly seen uses and formats: 1080p denotes the resolution and type of scanning compression used. Almost all videos for web are compressed with the H.264 codec, but streaming players will often create lower resolution versions of the video files. Codecs What it is? Codecs are programming languages used to compress video files and determine what type of information is included in the final video file. Why care? There are currently over 50 different video codecs for video files, most of which are outdated or only appear in certain instances or products. It is not necessary, even for experienced video professionals, to know them all – knowing the key players is enough. The most common cross-platform video codec for web video is H.264. This is also the codec of choice for mobile devices. The native video codec for Apple computers is Apple ProRes 422, while the native video codec for Windows is MPEG-2 Windows Media Video 9. This, combined with differences in containers, often leads to an inability to open video files on the operating system they were not originally compressed for without installing external plug-ins. However, as the world becomes a BYOD environment, and video becomes more widely available, use of these codecs is beginning to diminish rapidly. Commonly seen uses and formats: You may ask, “Why doesn’t everyone use H.264?” H.264 was created as a web standard, and is optimized for web video, but it is a lossy compression codec (a lot of information from the source picture is lost), which can be problematic for editing. Be sure to check, if you are creating a video bound for somewhere other than YouTube, what codec is the best match for your final format. Containers What it is? A container is a fancy word for a file type. It is represented by the set of letters that come after the last period in a file. Why care? The container for a video will determine whether or not the operating system recognizes it as a video file. Some applications only accept video files in certain containers. The H.264 codec is not specific to a container, and can be contained in .mov, .mp4, .flv, or .f4v files, but most other containers use specific codecs. One particularly powerful container (.mkv) even combines multiple files within a single file, including a video stream, an audio stream, and multiple subtitle tracks within a single container. Commonly seen uses and formats: The native container for Mac computers is .mov. The two native containers for Windows are .avi and .wmv. The most common cross-platform container is .mp4. Just remember, if you are creating video for a specific purpose, there is more to the equation than just codec and compression. If you publish a video in the wrong container, the device that is opening the video file won’t even recognize it as a video file. Want more? Try this article: http://www.techhive.com/article/213612/all_about_video_codecs_and_containers.html

Quick Table of Common Video Terms and Codecs Definition Most Common Use SD Standard Definition – The digital resolution of DVD video. Video compressed with at least 400 pixels vertical resolution. Older videos, videos compressed for mobile devices, and videos compressed for lower bandwidth streaming. HD/True HD High Definition – Videos compressed with at least 700 or 1080 (sometimes called True HD) vertical pixel height. Movies for Blu-Ray, television/cable, and hi-resolution streaming .MP4 Video container with cross-platform support. Lossy compression. Web Videos (YouTube, etc.), videos for mobile devices .MOV Video container designed to be read by the Quicktime Video Player. Videos for download, high-end editing formats, and occasionally web video (depending on codec used) .AVI Video container and codec pair for relatively lossless video on Windows operating systems Same as .MOV, but for Windows machines .WMV Microsoft proprietary video container and codec. Videos purchased for viewing with Windows Media Player. H.264 Video codec that is the current web standard for HTML5 . Lossy compression YouTube videos, mobile devices .FLV/.F4V Video container for Adobe’s Flash video. Plays natively in flash assets. Flash-based websites, Youtube for desktop