Comcast Archives – Page 3 of 4 – The Broadcast Knowledge

Video: Speed-Distortion Optimization: Tradeoffs in Open Source HEVC Encoding

Posted on 30th January 2020 by Russell Trafford-Jones

HEVC, also known as h.265, has been with us for 7 years and whilst its use continues to grow, its penetration remains low in streaming and broadcast transmissions. One reason for this is the increase in compute power it requires. With 4-rung ABR ladder for streaming being so common, a two-fold increase in complexity means finding 8 times as much compute power in your encoder.

This talk, led by MulticoreWare and Comcast, discusses the x.265 codec and the abilities of the presets. Pradeep Ramachandran uses a diagram of the x.265 encode system to expose some of the ways in which x.264 works.

Pradeep then gives an overview of the key tools of HEVC ahead of explaining those they tested against using UHD HDR content. Alex Giladi then takes the stage detailing their use of Dynamically Controlled RDO and how they were able to determine the best combination of modes to create the best encode.

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Speakers

	Pradeep Ramachandran Principal Engineer in Office of CTO, MulticoreWare
	Alex Giladi Distinguished Engineer, Comcast

Video: Non-standard Codecs with Standard WebRTC

Posted on 29th January 2020 by Russell Trafford-Jones

WebRTC is used on a massive scale thanks to Facebook messenger and Google, but when it comes to video streaming services, some find its open source codec VP8 too restrictive. WebRTC is actively evolving to adapt and become codec agnostic though this work is ongoing. In the meantime, Comcast is here to show us there is a way to inject the codec of your choice into WebRTC.

Finding that many of their video capture devices, CCTV cameras and the like, had hardware AVC encoders, Bryan Meissner explains Comcast didn’t feel it had much of a choice in codec, therefore they looked for a way to make WebRTC to carry AVC.

While forcing an unsupported codec into a protocol wasn’t ideal, they were able to leave much of WebRTC unchanged. The RTP and Data channels were established as normal and peering continued to work as ever. With control of both the send and receive side, the team found they could pick out the data from the WebRTC stack ahead of the normal decoder and feed that into Exoplayer using its API. This allowed playback on Android devices. Bryan goes on to explain the approach for iOS and web browsers. As WebRTC is ‘baked in’ to browsers, there really are very few ways to change the signal flow.

At the end of the day, Comcast made this work and used it in production or many years, Jeff Cardillo explains as he wraps up this video. But he also takes time to talk through some of the problems. Having to bypass parts of a program with parts of another library does increase complexity. Not only does the code become more complex but the code becomes platform specific, you need control over the source and keeping the individual parts synchronously up to date can be a balancing act.

Jeff finishes this talk from Demuxed SF 2019 by elaborating on the mobile and browser tradeoffs at play.

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Speakers

	Bryan Meissner Sr. Director Software Development and Engineering, Comcast
	Jeff Cardillo Principal Software Engineer, Comcast Interactive Media

Video: Codec Comparison from TCO and Compression Efficiency Perspective

Posted on 26th November 2019 by Russell Trafford-Jones

AVC, now 16 years old, is long in the tooth but supported by billions of devices. The impetus to replace it comes from the drive to serve customers with a lower cost/base and a more capable platform. Cue the new contenders VVC and AV1 – not to mention HEVC. It’s no surprise they comptes better then AVC (also known as MPEG 4 and h.264) but do they deliver a cost efficient, legally safe codec on which to build a business?

Thierry Fautier has done the measurements and presents them in this talk. Thierry explains that the tests were done using reference code which, though unoptimised for speed, should represent the best quality possible from each codec and compared 1080p video all of which is reproduced in the IBC conference paper.

Licensing is one important topic as, by some, HEVC is seen as a failed codec not in terms of its compression but rather in the réticente by many companies to deploy it which has been due to the business risk of uncertain licensing costs and/or the expense of the known licensing costs. VVC faces the challenge of entering the market and avoiding these concerns which MPEG is determined to do.

Thierry concludes by comparing AVC against HEVC, AV1 and VVC in terms of deployment dates, deployed devices and the deployment environment. He looks at the challenge of moving large video libraries over to high-complexity codecs due to cost and time required to re-compress. The session ends with questions from the audience.
Watch now!
Speaker

Thierry Fautier
President-Chair at Ultra HD Forum,
VP Video Strategy, Harmonic

Video: Mitigating Online Video Delivery Latency

Posted on 1st November 2019 by Russell Trafford-Jones

Real-world solutions to real-world streaming latency in this panel from the Content Delivery Summit at Streaming Media East. With everyone chasing reductions in latency, many with the goal of matching traditional broadcast latencies, there are a heap of tricks and techniques at each stage of the distribution chain to get things done quicker.

The panel starts by surveying the way these companies are already serving video. Comcast, for example, are reducing latency by extending their network to edge CDNs. Anevia identified encoding as latency-introducer number 1 with packaging at number 2.

Bitmovin’s Igor Oreper talks about Periscope’s work with low-latency HLS (LHLS) explaining how Bitmovin deployed their player with Twitter and worked closely with them to ensure LHLS worked seamlessly. Periscope’s LHLS is documented in this blog post.

The panel shares techniques for avoiding latency such as keeping ABR ladders small to ensure CDNs cache all the segments. Damien from Anevia points out that low latency can quickly become pointless if you end up with a low-latency stream arriving on an iPhone before Android; relative latency is really important and can be more so than absolute latency.

The importance of HTTP and the version is next up for discussion. HTTP 1.1 is still widely used but there’s increasing interest in HTTP 2 and QUIC which both handle connections better and reduce overheads thus reducing latency, though often only slightly.

The panel finishes with a Q&A after discussing how to operate in multi-CDN environments.

Watch now!
Speakers

	Damien Lucas CTO & Co-Founder, Anevia
	Ryan Durfey CDN Senior Product Manager, Comcast Technology Solutions
	Igor Oreper Vice President, Solutions Bitmovin
	Eric Klein Director, Content Distribution, Disney Streaming Services (was BAMTECH Media)
	Dom Robinson Director, id3as

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