Standards body MPEG is lining up two new codecs as stop gaps
before its next-generation heavyweight codec VVC comes on line in a move which
could both stimulate and muddy the market for live and on demand
streaming.
As if the codec space wasn’t crowded enough, MPEG is
entertaining the prospect of not one but two more standards for video delivery
within the next couple of years.
Its recent call for proposals for two new codec technologies
can be seen an attempt by the standards body to force HEVC license holders,
including its own division MPEG LA, to reduce the terms of their license
demands.
“Earlier this year the industry realised that new codecs
were coming and started to panic but the result is that the market is getting
even more fragmented,” says Thierry Fautier, chair of the Ultra HD Forum and VP
video strategy at Harmonic.
“HEVC works and has 2 billion installed devices but the
problem is the licensing. MPEG may feel that the more pressure that can be put
on HEVC, the more it will give in.”
Samsung’s codec
The first proposal is for a new video coding standard “to
address combinations of technical and application requirements that may not be
adequately met by existing standards”.
As MPEG points out, coding efficiency is not the only factor
that determines industry choice of video coding technology for products and
services. There’s the cost implication too. To which one might add, politics.
The focus of this new video coding standard is on use cases
such as offline encoding for streaming video on demand and live over-the-top
streaming. The aim is to provide a standardised solution which combines
efficiency similar to that of HEVC “with a level of complexity suitable for
real-time encoding and decoding and the timely availability of licensing
terms.”
Essentially this is what the Alliance for Open Media (AOM)
is already doing with its AV1 codec.
If you are a consumer electronics manufacturer like Apple
being charged even 1 dollar per device you sell to use the HEVC codec then
that’s at least $200 million per year off the bottom line. In reality the cost
could be more than this, added to which is the uncertainty around the actual
licensing costs which certain other HEVC license holders will apply.
But that’s not all. Apple is a member of AOM but noticeably
absent is its big rival Samsung. No surprise then that Samsung is the chief
and, to our knowledge, only backer of this new video coding standard under
proposal at MPEG.
V-Nova’s codec
The second codec being considered by MPEG is actually an
existing technology which acts to enhance the deployment of hardware codecs
processing MPEG4/H.264 AVC and HEVC.
It is calling on the industry to propose solutions for ‘low
complexity video coding enhancements’ and further explains that the objective
is to develop a codec which has a base stream decodable by a hardware
decoder overlaid by a software layer which will improve the hardware’s
compression efficiency.
The target once again is live and on demand video streaming.
The argument here is sound – instead of waiting for a new
codec to come along what if it were possible today to add software which
improves compression efficiency and which also saves on broadcasters having to
rip and replace their existing (AVC, HEVC) codec investments?
Turns out this is entirely possible since the initiative is
designed around the Perseus Plus technology devised by V-Nova.
“MPEG wants to standardise what V-Nova does,” says Fautier.
“So far their success was limited, one reason [being] is this is not [yet] a
standard based solution.”
Any other vendor can submit a proposal for MPEG evaluation
but it’s likely that V-Nova’s will win the day since it’s already in the market
and MPEG’s specs fit the Perseus design.
“AVC and HEVC are massively supported by various platforms
and hardware solutions/assistance is provided on many devices,” says Christian
Timmerer, who speaks for MPEG.
“However, it has been shown that software solutions can
enhance quality significantly which can provide a better quality of experience
for the end user at lower (or equal) bitrate but with some additional
processing efforts to be done on the terminal side.”
V-Nova itself claims that at or below HD resolutions,
Perseus improves H.264 performance by more than 40% and at UHD resolutions improves
HEVC performances by 70%.
Although its solution would not be royalty free, it will
argue that its approach addresses the large installed base of AVC today such
that broadcasters don’t have to change their decoder to HEVC or expose
themselves to HEVC license terms.
“We welcome the efforts made by both MPEG and AOM to develop
codecs, however, we are also conscious of the fact that lead times for new
codecs are long and replacement cycles of devices in the field often even
longer,” says Fabio Murra, SVP product & marketing, V-Nova.
“As such, this
approach represents a game-changing opportunity, now and in the future, to
accelerate the deployment of more advanced compression between the longer
cycles of codec evolution.”
MPEG’s call for low complexity video coding enhancements is
not only intended to enhance any existing video codec but could be used to
provide an upgrade to any future codec.
“There is rapidly growing interest in enhancing compression
efficiency, and doing so without necessarily requiring new hardware is
something the industry and our customers find compelling,” states Murra.
Content Aware Encoding
It is an approach, though, that is competitive with Content
Aware Encoding (CAE) for OTT, a technique that also does not need to change the
decoder, and is supported by Apple’s operating system for mobile iOS11.
“We believe the most reliable approach is to focus on
improving the codec implementation” - Mark Donnigan, Beamr
In contrast to encoding using ABR (Adaptive Bit Rate) where
each resolution such as HD or SD is matched to a given bit rate, CAE can make
more efficient use of bandwidth, particularly in live streaming scenarios.
The leaders in this field are Harmonic (which markets
EyeQ content-aware encoding software), Brightcove (which includes CAE in
its online video platform) and Beamr (which deploys a patented content-adaptive
bitrate solution, CABR, over HEVC).
“Beamr can reach high quality video at additional savings of
as much as 40% over a comparable HEVC encode using our CABR mode, which in my
mind obfuscates the need for an ‘enhancement’ layer,” says Mark Donnigan, vice
president, marketing, Beamr.
The Isreali and Palo Alto-based outfit has achieved greater
than a 50% improvement in the bitrate efficiency of its HEVC codec from first
launch five years ago. Since its tech is integrated with the rate-control of
the encoder it means that, in theory, CABR could be used with a dual-layer
approach.
However, Donnigan maintains that since CABR often leads to
bitrate reductions of an additional 30-40%, “a user adopting CABR won’t likely
need the added implementation complexity of a dual-layer solution to meet their
objective for high quality at lower bitrate.”
He says, “The question that must be asked is whether the
benefits of the additional complexity such as the MPEG committee is calling
for, are worth it? We believe the most reliable approach is to focus on
improving the codec implementation, which when combined with content-adaptive
technology such as CABR, will yield a benefit for all devices with HEVC
decoders today - no updates required.”
He argues that the importance of playback compatibility
is often overlooked by every new codec or technology enhancement.
“As a striking example, this is the situation right now with
AV1, where there are encoding vendors offering solutions for creating AV1
compatible files, but - outside of a very narrow combination of a desktop
computer and a beta browser - the files cannot be played back where consumers
want to consume the content such as on a mobile device, TV, game console or
media player.
“The fact is, with a well-designed implementation of an
existing codec such as HEVC, [new codecs] are not required,” he says.
Donnigan believes that MPEG’s proposal for low complexity
video coding enhancements is “an academic initiative” that will not have
commercial appeal because the complexities of developing and implementing it
outweigh the codec efficiency that he says Beamr delivers today.
“And we deliver efficiency completely inside the standard of
HEVC with no changes required to the decoder or player application.”
Whatever happens with the Samsung or the V-Nova promoted
proposals, it will be many months before either gains standard status as the
proposals move within MPEG. It’s not a sluggish organisation – far from it.
It’s got multiple standards efforts on the go all the time for which the
process includes working drafts in multiple iterations until a final draft gets
the vote of national bodies. According to Timmerer, that could take two years
(or more) depending on the number of contributions.
By then in 2020 MPEG’s main next gen codec initiative will
be about due. This is VVC (Versatile Video Codec) which could well trump every
other codec out there.
What’s more there’s an independent body to police the whole
situation and prevent the mess which the industry has got itself into with the
lack of clarity around HEVC licensing.
The Media Coding Industry Forum (MC-IF), launched at
IBC2018, and has companies like Canon, MediaKind, Sony, Nokia as well as Apple
on board. HEVC Advance, one of the HEVC patent holding pools is also a member.
Speaking without his MPEG hat, Timmerer admits, “We are
entering a situation with multiple codecs and this might be a problem in terms
of market fragmentation but usually the market will make its decision one way
or another.”
Referring to AV1 and other codec upstarts, Fautier says “VVC
will wipe out all these monkey codecs, assuming it can be licensed to
everyone’s satisfaction. Development has to go hand in hand with common sense.”
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