Three Things Worth Knowing About Video Compression

Video is fast becoming a lynchpin in today’s communication mix and it is easy to get dogged down when trying to understand how streaming video works, given the numerous standards used for compression and the plethora of devices plus software. In recent posts the video compression contestants in the market, their solutions and patent strategies were reviewed. In this post I’ll highlight three things worth knowing about video streaming and compression that further illuminate the technology and its use.

The first fact explains why the current compression standard H.264 might enjoy a longer life than many may think.

The second fact helps us understand how to identify what type of video compression is being used.

The third fact highlights the all important role of the browser for mobile and desktop video viewing and untangles its relation to different compression standards.

Squeezing Legacy H.264 Until the Pips Squeek

Upgrading from H.264 to a next-gen codec technology such as H.265 or VP9 certainly frees up bandwidth and memory requirements for transmitting or storing video, but it is a gamble for players in the ecosystem because it demands substantial investment in new equipment without prior knowledge as to which of the next-gen standards will prevail and when they might disrupt the current mainstream standard. Instead, many prefer to squeeze more life out of the popular H.264 codec. That’s possible because any video codec essentially only specifies the syntax of the (compressed) video stream, and not the method used to encode and decode it.

Thus there are a number of technology companies around who provide enhancements to existing H.264 codecs that further reduce the bit rate without any perceptible quality degradation. Companies who offer solutions here include Beamer, Faroudja, and EuclidIQ amongst others.

Understanding Containers and Codecs

To play back compressed or uncompressed videos on your PC or device, many of you will probably have used files with extensions such as .avi (Audio Video Interleave), .wmv (Windows Media Format), .flv or .swf (Adobe Flash), .mov (Apple QuickTime), .webm (Google WebM) or .mp4 (MPEG–4 Part 14).

So where does the codec fall into this scheme of things? The file extensions mentioned above are so-called container formats that allow a combination of audio, video, subtitles and still images to be held in one single file. Video or audio in such a file container may be uncompressed or compressed. Multiple video (and audio) compression standards in a single container may also be supported. It just depends on the container. Indeed, there are hundreds of container/codec combinations. But the predominant ones are the MPEG4 container that supports the H.264 video codec in combination with AAC and MP3 audio codecs and Google’s WebM container that supports its VP8 and VP9 codec in combination with the Vorbis and Opus audio codecs.

Browsers and Video Codec Support

Web pages viewed in browsers use the HyperText Markup Language (HTML) to render content. In the past it was necessary to add a browser plug-in to view video within a browser. An example is Adobe’s Flash product which is a video plug-in supported by the majority of browsers. Back in 2007 Adobe licensed the H.264 codec making video playback free for all PC and notebook users whose browsers supported adding the Flash plug-in.

Today however, HTML5 allows embedding video directly using the <video> tag, eliminating the need for third-party plugins like Flash (Adobe) or Silverlight (Microsoft). Thus video codec support now depends on the browser used and the underlying arrangements between the browser/operating system/chip decoder vendors with the codec creator.

The table below shows the state of browser codec support in late 2015.

It’s a patchy support landscape to date and a fast-moving target too. The website Can I use is an excellent source for a quick check on the latest support because it provides up-to-date tables of supported front-end web technologies for desktop and mobile browsers.

Google’s Chrome might seem like a good choice now in terms of video support today, however industry insiders claim that Microsoft’s latest Edge browser is due to support HEVC (MPEG4) soon too.

As the codec wars wage, consumers are faced with a murky picture of what works and where in terms of online video - a consistent source of frustration and the price we pay for getting it all free.