December 6, 2018
By Tim Siglin Contributing Editor, Steve Nathans-Kelly
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SMW '18: Twitch's Tarek Amara Talks Multi-Codec Streaming

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Read the complete transcript of this interview:

Tim Siglin: And we're back with Streaming Media West 2018’s "Almost Live." I'm Tim Siglin, contributing editor with Streaming Media Magazine, and the founding Executive Director of Help Me! Stream. Today I've got with me Tarek Amara from Twitch. Tarek, what's your title at Twitch?

Tarek Amara: I'm a Senior Video Specialist. My job is mainly part of the transcoding team, and my responsibility is to make sure we stream good video for the present, whether it is on the backbone infrastructure, or any future technology that we need to incorporate at Twitch.

Tim Siglin: And Twitch is primarily live content, right?

Tarek Amara: It's 99 point-something percent live. We started a VOD service, and a clip service as well, but the live is the main driver.

Tim Siglin: Which is interesting, because I remember way back in the early days, with Justin.tv and life-casting, which was an anomaly, because everyone else was doing VOD, and he wanted to do fully live. So, obviously, the heritage is continued through Twitch.

Tarek Amara: Absolutely. And Justin.TV is still driving Twitch to a big extent. It's funny you bring that up. Before I joined Twitch, I knew a little bit about Justin.TV, and I know all the kind of content that people used to stream on Justin.Tv. Now, Twitch is focused on mainly eSports, which is growing as well. So, it's opening the door for different content.

Tim Siglin: If you're focused on live, you're focused on the transcoding, and those kinds of things, you're looking, in that scenario, to transcode for multiple platforms to view live.

Tarek Amara: We try to make sure we deliver the best video quality, the best service, the lowest latency, the pristine video quality and quality of service, even on H.264 today. We do deliver our content to browsers, mobile devices, consoles, but we're still not a living room experience yet. We don't have lots of minutes consumed on TVs, but mobile devices and browsers are the main drivers. And now we’re moving from a single-codec company to deliver multiple codecs, and that's where VP9 falls in, and that's just to diversify, to make sure to deliver better quality of service, lower bitrates of the same quality, and to save on the cost of delivery as well.

Tim Siglin: It's interesting you mention that, having done a lot of work in the past with Adobe and other companies who had to address with Flash multiple codecs, multiple delivery scenarios, and as we've moved to this sort of HTML5 world, where we assumed everybody was doing H.264, in reality there were a lot of devices that worked better with VP9, or work as well with VP9.

Tarek Amara: Absolutely. Our study says, first of all, the alternative to VP9 probably would be HEVC. And if you look up browser sites, specifically Chrome and Firefox, they're not deploying HEVC. So that's already segmenting the market to an extent. Lots of mobile devices have got good VP9 support, with harder acceleration, which makes it more valuable and more of a real solution. Lots of VOD players have been starting to stream VP9, so they're making the platform slightly mature for us, when we came in with the live streaming. Our challenge is more of the real-timing encoding side, which the VOD people that can hour to encode, for us it must be real-time VP9, and that's very scarce.

Tim Siglin: And you also have a decent number of devices with embedded VP9 decoding.

Tarek Amara: Absolutely, and that's probably why we prefer VP9 to HEVC at this stage.

Tim Siglin: Understood. You mentioned Firefox, where we had the whole war a couple years ago, with open video standards. In fact, one of the previous guests on here was from Wikipedia, and had helped push some of that, where Mozilla wasn't going to do 264. And then, suddenly, the ...

Tarek Amara: I agree. Just to add to that, we're talking to the Google Chrome team specifically, they said if VP6 was ready early enough, they wouldn't have deployed H.264. And now their attitude is, "We're not going to deploy HEVC," specifically because VP9 is showing some success, even more mature, with a bigger community around it, AV1 is the future for them. And we don't dictate what standard we use. We're kind of driven by our audience.

Tim Siglin: If I was a sports bookie, I'd take odds on the fact that they will eventually do HEVC, but you're right, they've got AV1 in the pipeline, they've got VP9, of course. So, beyond the codec challenges, what are the other challenges in transcoding for a 99.9% live platform?

Tarek Amara: First of all, historically, our platform used to be H.264-centric, so it's a single codec. So, moving from that to multiple codec is not just plugging in another encoder.

Tim Siglin: It's rearranging the pipeline.

Tarek Amara: Lots of stuff needs to be rewritten from scratch. We've been working so hard on keeping lower latency. Whatever new transcoding technology you bring in, it must be able to deliver comparable, if not better, latency moving forward.

The other thing I would say is, probably all the features we offer today on the Twitch platform, from adding server-based ad insertion, from clips, which is an option ... All these features need to be supported with any new video technology we provide. So, we need to bring in new codec technology to keep what we have and add to it, not to go backwards.

Tim Siglin: Sure. Now, you're owned by Amazon, and one of the conversations that I've heard at the show today is about microservices on AWS. Do you all use Amazon platform, do you have your own solutions, or how does that work?

Tarek Amara: For lots of services, we do use AWS. For the transcoded pipeline itself, which is, from ingesting the video, decoding it, checking it, sending it to a transcoded form, that is still in-house. But, interestingly, the technology we are using at the moment to leverage VP9--the hardware technology comes from Amazon. So, that will allow us eventually either to be on-premises, or we can leverage or offload some of the excess transcode tasks to AWS. The possibility is there.

Tim Siglin: Okay. And, obviously, that possibility is because you're rethinking the entire thing from being single-codec centered to multi-codec.

Tarek Amara: Absolutely.

Tim Siglin: Tarek, thank you for your time. Tarek Amara with Twitch. We'll be right back after a short break.