Video: Comparison of EVC and VVC against HEVC and AV1

AV1’s royalty-free status continues to be very appealing, but in raw compression is it losing ground now to the newer codecs such as VVC? EVC has also introduced a royalty-free model which could also detract from AV1’s appeal and certainly is an improvement over HEVC’s patent debacle. We have very much moved into an ecosystem of patents rather than the MPEG2/AVC ‘monoculture’ of the 90s within broadcast. What better way to get a feel for the codecs but to put them to the test?

Dan Grois from Comcast has been looking at the new codecs VVC and EVC against AV1 and HEVC. VVC and EVC were both released last year and join LCEVC as the three most recent video codecs from MPEG (VVC was a collaboration between MPEG and ITU). In the same way, HEVC is known as H.265, VVC can be called H.266 and it draws its heritage from the HEVC too. EVC, on the other hand, is a new beast whose roots are absolutely shared with much of MPEG’s previous DCT-based codecs, but uniquely it has a mode that is totally royalty-free. Moreover, its high-performant mode which does include patented technology can be configured to exclude any individual patents that you don’t wish to use thus adding some confidence that businesses remain in control of their liabilities.

Dan starts by outlining the main features of the four codecs discussing their partitioning methods and prediction capabilities which range from inter-picture, intra-picture and predicting chroma from the luma picture. Some of these techniques have been tackled in previous talks such as this one, also from Mile High Video and this EVC overview and, finally, this excellent deep dive from SMPTE in to all of the codecs discussed today plus LCEVC.

Dan explains the testing he did which was based on the reference encoder models. These are encoders that implement all of the features of a codec but are not necessarily optimised for speed like a real-world implementation would be. Part of the work delivering real-world implementations is using sophisticated optimisations to get the maths done quickly and some is choosing which parts of the standard to implement. A reference encoder doesn’t skimp on implementation complexity, and there is seldom much time to optimise speed. However, they are well known and can be used to benchmark codecs against each other. AV1 was tested in two configurations since

AV1 needs special treatment in this comparison. Dan explains that AV1 doesn’t have the same approach to GOPs as MPEG so it’s well known that fixing its QP will make it inefficient, however, this is what’s necessary for a fair comparison so, in addition to this, it’s also run in VBR mode which allows it to use its GOP structure to the full such as AV1’s invisible frames which carry data which can be referenced by other frames but which are never actually displayed.

The videos tested range from 4K 10bit down to low resolution 8 bit. As expected VVC outperforms all other codecs. Against HEVC, it’s around 40% better though carrying with it a factor of 10 increase in encoding complexity. Note that these objective metrics tend to underrepresent subjective metrics by 5-10%. EVC consistently achieved 25 to 30% improvements over HEVC with only 4.5x the encoder complexity. As expected AV1’s fixed QP mode underperformed and increased data rate on anything which wasn’t UHD material but when run in VBR mode managed 20% over HEVC with only a 3x increase in complexity.

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Speaker

Dan Grois Dan Grois
Principal Researcher,
Comcast

Video: Codecs, standards and UHD formats – where is the industry headed?

Now Available On Demand
UHD transmissions have been available for many years now and form a growing, albeit slow-growing, percentage of channels available. The fact that major players such as Sky and BT Sports in the UK, NBCUniversal and the ailing DirecTV in the US, see fit to broadcast sports in UHD shows that the technology is trusted and mature. But given the prevalence of 4K in films from Netflix, Apple TV+ streaming is actually the largest delivery mechanism for 4K/UHD video into the home.

Following on from last week’s DVB webinar, now available on demand, this webinar from the DVB Project replaces what would have been part of the DVB World 2020 conference and looks at the work that’s gone into getting UHD to were it is now in terms of developing HEVC (also known as H.265), integrating it into broadcast standards plus getting manufacturer support. It then finishes by looking at the successor to HEVC – VVC (Versatile Video Codec)

The host, Ben Swchwarz from the Ultra HD Forum, first introduces Ralf Schaefer who explores the work that was done in order to make UHD for distribution a reality. He’ll do this by looking at the specifications and standards that were created in order to get us where we are today before looking ahead to see what may come next.

Yvonne Thomas from the UK’s Digital TV Group is next and will follow on from Ben by looking at codecs for video and audio. HEVC is seen as the go-to codec for UHD distribution. As the uncompressed bitrate for UHD is often 12Gbps, HEVC’s higher compression ratio compared to AVC and relatively wide adoption makes it a good choice for wide dissemination of a signal. But UHD is more than just video. With UHD and 4K services usually carrying sports or films, ‘next generation audio‘ is really important. Yvonne looks at the video and audio aspects of delivering HEVC and the devices that need to receive it.

Finally we look at VVC, also known as H.266, the successor to HEVC, also known as H.265. ATEME’s Sassan Pejhan gives us a look into why VVC was created, where it currently is within MPEG standardisation and what it aims to achieve in terms of compression. VVC has been covered previously on The Broadcast Knowledge in dedicated talks such as ‘VVC, EVC, LCEVC, WTF?’, ‘VVC Standard on the Final Stretch’, and AV1/VVC Update.

No Registration Necessary!

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Speakers

Ben Schwarz Ben Schwarz
Communication Working Group Chair,
Ultra HD Forum
Ralf Schaefer Ralf Schaefer
VP Standards R&I
InterDigital Inc.
Yvonne Thomas Yvonne Thomas
Strategic Technologist
DTG (Digital TV Group)
Sassan Pejhan Sassan Pejhan
VP Technology,
ATEME