Video Codecs Today: Minefield, Muddle, or Multiple Choice?
The pressure to optimize delivery of video at ever higher bitrates is growing such that the traditional once-in-a-decade leap in compression standards is on the verge of disintegrating.
It’s not that codec development is being outpaced; rather, that advances made in this area driven by the explosion in video over IP are creating heated competition and a fragmented market.
The latest to join battle is MPEG-5, (AKA Essential Video Coding/EVC), which standards body MPEG has put on a rapid track to ratification by this time next year. MPEG will talk about this at the NAB Show next week.
It’s yet another attempt to bypass HEVC, which has been bogged down by perceived or actual high cost of implementation even while its technical benefits are not in question and its install base of 2 billion device continues to rise.
EVC will be royalty-free and aimed to be at least as efficient as HEVC. In tests, this target has reportedly been exceeded by 24%. But royalty-free codec AV1 is already in the market while MPEG’s own Versatile Video Coding (VVC) which targets immersive media applications and has greater target efficiency is due October 2020.
Meanwhile, Samsung began proposing its own AV1-style codec through MPEG seemingly because Apple is a member of AV1-backers Alliance for Open Media. Since the South Korean firm has just announced its own participation in AOM it's unclear where the fate of this proposal resides.
V-Nova is hoping to get its Perseus Plus codec accepted by MPEG as a standard means to enhance the deployment of codecs processing H.264 and H.265. This is something it already does, but you can’t blame V-Nova for wanting official MPEG backing. It’s an approach, though, that rivals Content Aware Encoding for OTT, a technique that also does not require clients to swap out their hardware decoder.
An outside alternative is from Sweden’s Divideon whose XVC codec is being pitched as a compromise between HEVC and AV1.
The Media Coding Industry Forum, which launched six months ago and includes companies like Canon, MediaKind, Sony, Nokia, and Apple, will have its work cut out policing all of this to avoid another HEVC licence debacle, although it’s worth noting that HEVC patent holder HEVC Advance is also a member.
MPEG may feel the more pressure put on HEVC, the more it will give in over licence issues, but the genie is well and truly out of the bottle.
What seems more likely is that a number of these options could enjoy wide adoption. As analyst Futuresource points out, “Broadcasters may favour VVC and streaming services could utilise XVC or AV1.”
The market needs a codec that delivers high compression efficiency, reasonable encoder complexity, broad decoder support, and a clear licensing scheme. There are clear questions of scale and the market will need to move to an all-software base, but just as cinematographers now pick digital sensors as they would film stock for different applications, so broadcasters and service providers might one day be able to cherry pick, swap, and replace codecs with automated ease.
The fragmented, frustrating future of HEVC licensing dominated discussion at the Media Coding Industry Forum's recent meeting, which attempted to influence licensing for the upcoming Versatile Video Codec.
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Is AV1 all that people expect it to be? How much better would HEVC be doing with a fair royalty policy? Look to these charts for the answers to tomorrow's codec questions.
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