Twitch is constantly searching for better and lower cost ways of streaming and its move to include VP9 was one of the most high profile ways of doing this. In this talk, a team of Twitch engineers examine the reasons for this and other moves.
Tarek Amara first takes to the stage to introduce Twitch and its scale before looking at the codecs available, the fragmentation of support but also the drivers to improve the video delivered to viewers both in terms of frame rate and resolution in addition to quality. The discussion turns to the reasons to implement of VP9 and we see that if HEVC were chosen instead, less than 3% of people would be able to receive it.
Nagendra Babu explains the basic architecture employed at Twitch before going on to explain the challenges they met in testing and developing the backend and app. He also talks about the difficulty of running multiple transcodes in the cloud. FPGAs are in important tool for Twitch, and Nagendra discusses how they deal with their programming.
The last speaker is Nikhil who talks about the format of VP9 being FMP4 delivered by transport stream and then outlines the pros and cons of Fragmented FMP4 before handing the floor to the audience.
If there’s any talk that cuts through the AV1 hype, it must be this one. The talk from the @Scale conference starts by re-introducing AV1 and AoM but then moves quickly on to encoding techniques and the toolsets now available in AV1.
Starting by looking at the evolution from VP9 to AV1, Google engineer Yue Chen looks at:
AV1 has strong backing from tech giants but is still seldom seen in the wild. Find out what the plans are for the future with Google’s Debargha Mukherjee.
Debargha’s intent in this talk is simple: to frame a description of what AV1 can do and is doing today in terms of the history of the codec and looking forward to the future and a potential AV2.
The talk starts by demonstrating the need for better video codecs not least of which is the statistic that by 2021, 81% of the internet’s traffic is expected to be video. But on top of that, there is a frustration with the slow decade-long refresh process which is traditional for video codecs. In order to match the new internet landscape with fast-evolving services, it seemed appropriate to have a codec which not only delivered better encoding but also saw a quicker five-year refresh cycle.
As a comparison to the royalty-free AV1, Debargha then looks at VP9 it is deployed. Further more, VP10 who’s development was stopped and diverted into the AV1 effort which is then the topic for the next part of the talk; the Alliance for Open Media, the standardisation process and then a look at some of the encoding tools available to archive the stated aims.
To round off the description of what’s presently happening with AV1 trials of VP9, HEVC and AV1 are shown demonstrating AV1s ability to improve compression for a certain quality. Bitmovin and Facebook’s tests are also highlighted along with speed tests.
Looking, now, to the future, the talk finishes by explaining the future roadmap for hardware decoding and other expected milestones in the coming years plus the software work such as SVT-AV1 and DAV1D for optimised encoding and decoding. With the promised five-year cycle, we need to look forward now to AV2 and Debargha discusses what it might be and what it would need to achieve.
The codec world is fragmenting. None of the new entrants on to the market is expected to ever gain the universal status that AVC enjoys. This panel from Streaming Media East takes a look at how to prepare for this.
The panel kicks off discussing the differences between AVC and HEVC, VP9 and AV1 and moves on to discuss the pros and cons of supporting multiple codecs. Tarek from Twitch explains its partial adoption of VP9 – the reasons that it makes sense but the overheads which it brings the business.
Vittorio Giovara from Vimeo explains their reasons for using HEVC including their drive to be able to encode and deliver 10-bit video. Ellation’s Subhrendu Sarakar makes the point that managing codec changes and bitrate changes needs to be done carefully to ensure viewers that notice the change understand them and don’t feel there has been a reduction of quality.
After a brief discussion of encoding strongly characterised video types such as anime and gaming, the conversation moves on to AV1 and migrating from VP9 and there is an audience question on HEVC licensing and the lack of use of SVC (Scalable Video Coding)
It’s now relatively well known that Twitch deployed VP9 using FPGAs rather than as a software encoder which was the only way to get the real-time speed at 1080p60. The panel discusses encoding speed both in the encoder and decoder for VP9 and AV1 then finishes with a Q&A from the audience.