Video: Low Latency Streaming

There are two phases to reducing streaming latency. One is to optimise the system you already have, the other is to move to a new protocol. This talk looks at both approaches achieving parity with traditional broadcast media through optimisation and ‘better than’ by using CMAF.

In this video from the Northern Waves 2019 conference, Koen van Benschop from Deutsche Telekom examines the large and low-cost latency savings you can achieve by optimising your current HLS delivery. With the original chunk sizes recommended by Apple being 10 seconds, there are still many services out there which are starting from a very high latency so there are savings to be had.

Koen explains how the total latency is made up by looking at the decode, encode, packaging and other latencies. We quickly see that the player buffer is one of the largest, the second being the encode latency. We explore the pros and cons of reducing these and see that the overall latency can fall to or even below traditional broadcast latency depending, of course, on which type (and which country’s) you are comparing it too.

While optimising HLS/DASH gets you down to a few seconds, there’s a strong desire for some services to beat that. Whilst the broadcasters themselves may be reticent to do this, not wanting to deliver online services quicker than their over-the-air offerings, online sports services such as DAZN can make latency a USP and deliver better value to fans. After all, DAZN and similar services benefit from low-second latency as it helps bring them in line with social media which can have very low latency when it comes to key events such as goals and points being scored in live matches.

Stefan Arbanowski from Fraunhofer leads us through CMAF covering what it is, the upcoming second edition and how it works. He covers its ability to use .m3u8 (from HLS) and .mpd (from DASH) playlist/manifest files and that it works both with fMP4 and ISO BMFF. One benefit from DASH is it’s Common Encryption standard. Using this it can work with PlayReady DRM, Fairplay and others.

Stefan then takes a moment to consider WebRTC. Given it proposes latency of less than one second, it can sound like a much better idea. Stefan outlines concerns he has about the ability to scale above 200,000 users. He then turns his attention back to CMAF and outlines how the stream is composed and how the player logic works in order to successfully play at low latency.

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Speakers

Koen van Benschop Koen van Benschop
Senior Manager TV Headend and DRM,
Deutsche Telekom
Stefan Arbanowski Stefan Arbanowski
Director Future Applications and Media,
Fraunhofer FOKUS

Video: Mitigating Online Video Delivery Latency

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.

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Speakers

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

Video: Specification of Live Media Ingest

“Standardisation is more than just a player format”. There’s so much to a streaming service than the video, a whole ecosystem needs to work together. In this talk from Comcast’s Mile High Video 2019, we see how different parts of the ecosystem are being standardised for live ingest.

RTMP and Smooth streaming are being phased out – without proper support for HEVC, VVC, HDR etc. they are losing relevance as well as, in the case of RTMP, support from the format itself. Indeed it’s clear that fragmented MP4 (fMP4) and CMAF are taking hold in their place so it makes sense for a new ingest standard to coalesce around these formats.

Rufael Mekuria from Unified streaming explains this effort to create a spec around live media ingest that is happening as part of MPEG DASH-IF. The work itself started at the end of 2017 with the aim of publishing summer 2019 supporting CMAF and DASH/HLS interfaces.

Rufael explains CMAF ingest used HTTP post to move each media stream to the origin packager. The tracks are separated into video, audio, timed text, subtitle and timed metadata. They are all transferred on separate tracks and is compatible with future codecs. He also covers security and timed text before covering DASH/HLS ingest which can also contain CMAF because HLS contains the capability to contain CMAF.

Reference software is available along with the <a href=”http://”https://dashif-documents.azurewebsites.net/Ingest/master/DASH-IF-Ingest.pdf” rel=”noopener noreferrer” target=”_blank”>specification.

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Speaker

Rufael Mekuria Rufael Mekuria
Head of Research & Standardisation,
Unified Streaming

Video: WAVE (Web Application Video Ecosystem) Update

With wide membership including Apple, Comcast, Google, Disney, Bitmovin, Akamai and many others, the WAVE interoperability effort is tackling the difficulties web media encoding, playback and platform issues utilising global standards.

John Simmons from Microsoft takes us through the history of WAVE, looking at the changes in the industry since 2008 and WAVE’s involvement. CMAF represents an important milestone in technology recently which is entwined with WAVE’s activity backed by over 60 major companies.

The WAVE Content Specification is derived from the ISO/IEC standard, “Common media application format (CMAF) for segmented media”. CMAF is the container for the audio, video and other content. It’s not a protocol like DASH, HLS or RTMP, rather it’s more like an MPEG 2 transport stream. CMAF nowadays has a lot of interest in it due to its ability to delivery very low latency streaming of less than 4 seconds, but it’s also important because it represents a standardisation of fMP4 (fragmented MP4) practices.

The idea of standardising on CMAF allows for media profiles to be defined which specify how to encapsulate certain codecs (AV1, HEVC etc.) into the stream. Given it’s a published specification, other vendors will be able to inter-operate. Proof of the value of the WAVE project are the 3 amendments that John mentions issued from MPEG on the CMAF standard which have come directly from WAVE’s work in validating user requirements.

Whilst defining streaming is important in terms of helping in-cloud vendors work together and in allowing broadcasters to more easily build systems, its vital the decoder devices are on board too, and much work goes into the decoder-device side of things.

On top of having to deal with encoding and distribution, WAVE also specifies an HTML5 APIs interoperability with the aim of defining baseline web APIs to support media web apps and creating guidelines for media web app developers.

This talk was given at the Seattle Video Tech meetup.

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Slides from the presentation
Check out the free CTA specs

Speaker

John Simmons John Simmons
Media Platform Architect,
Microsoft