Video: DASH: from on-demand to large scale live for premium services

A bumper video here with 7 short talks from VideoLAN, Will Law and Hulu among others, all exploring the state of MPEG DASH today, the latest developments and the hot topics such as low latency, ad insertion, bandwidth prediction and one red letter feature of DASH – multi-DRM.

The first 10 minutes sets the scene introducing the DASH Industry Forum (DASH IF) and explaining who takes part and what it does. Thomas Stockhammer, who is chair of the Interoperability Working Group explains that DASH IF is made of companies, headline members including Google, Ericsson, Comcast and Thomas’ employer Qualcomm who are working to promote the adoption MPEG-DASH by working to imrove the specification, advise on how to put it into practice in real life, promote interoperability, and being a liaison point for other standards bodies. The remaining talks in this video exemplify the work which is being done by the group to push the technology forward.

Meeting Live Broadcast Requirements – the latest on DASH low latency!
Akamai’s Will Law takes to the mic next to look at the continuing push to make low-latency streaming available as a mainstream option for services to use. Will Law has spoken about about low latency at Demuxed 2019 when he discussed the three main file-based to deliver low latency DASH, LHLS and LL-HLS as well as his famous ‘Chunky Monkey’ talk where he explains how CMAF, an implementation of MPEG-DASH, works in light-hearted detail.

In today’s talk, Will sets out what ‘low latency’ is and revises how CMAF allows latencies of below 10 seconds to be achieved. A lot of people focus on the duration of the chunks in reducing latency and while it’s true that it’s hard to get low latency with 10 second chunk sizes, Will puts much more emphasis on the player buffer rather than the chunk size themselves in producing a low-latency stream. This is because even when you have very small chunk sizes, choosing when to start playing (immediately or waiting for the next chunk) can be an important part of keeping the latency down between live and your playback position. A common technique to manage that latency is to slightly increase and decrease playback speed in order to manage the gap without, hopefully, without the viewer noticing.

Chunk-based streaming protocols like HLS make Adaptive Bitrate (ABR) relatively easy whereby the player monitors the download of each chunk. If the, say, 5 second chunk arrives within 0.25 seconds, it knows it could safely choose a higher-bitrate chunk next time. If, however the chunk arrives in 4.8 seconds, it can choose to the next chunk to be lower-bitrate so as to receive the chunk with more headroom. With CMAF this is not easy to do since the segments all arrive in near real-time since the transferred files represent very small sections and are sent as soon as they are created. This problem is addressed in a later talk in this talk.

To finish off, Will talks about ‘Resync Elements’ which are a way of signalling mid-chunk IDRs. These help players find all the points which they can join a stream or switch bitrate which is important when some are not at the start of chunks. For live streams these are noted in the manifest file which Will walks through on screen.

Ad Insertion in Live Content:Pre-, Mid- and Post-rolling
Whilst not always a hit with viewers, ads are important to many services in terms of generating the revenue needed to continue delivering content to viewers. In order to provide targeted ads, to ensure they are available and to ensure that there is a record of which ads were played when, the ad-serving infrastructure is complex. Hulu’s Zachary Cava walks us through the parts of the infrastructure that are defined within DASH such as exchanging information on ‘Ad Decision Parameters’ and ad metadata.

In chunked streams, ads are inserted at chunk boundaries. This presents challenges in terms of making sure that certain parameters are maintained during this swap which is given the general name of ‘Content Splice Conditioning.’ This conditioning can align the first segment aligned with the period start time, for example. Zachary lays out the three options provided for this splice conditioning before finishing his talk covering prepared content recommendations, ad metadata and tracking.

Bandwidth Prediction for Multi-bitrate Streaming at Low Latency
Next up is Comcast’s Ali C. Begen who follows on from Will Law’s talk to cover bandwidth prediction when operating at low-latency. As an example of the problem, let’s look at HTTP/1.1 which allows us to download a file before it’s finished being written. This allows us to receive a 10-second chunk as it’s being written which means we’ll receive it at the same rate the live video is being encoded. As a consequence the time each chunk takes to arrive will be the same as the real-time chunk duration (in this example, 10 seconds.) When you are dealing with already-written chunks, your download time will be dependent on your bandwidth and therefore the time can be an indicator of whether your player should increase or decrease the bitrate of the stream it’s pulling. Getting back this indicator for low-latency streams is what Ali presents in this talk.

Based on this paper Ali co-authored with Christian Timmerer, he explains a way of looking at the idle time between consecutive chunks and using a sliding window to generate a bandwidth prediction.

Implementing DASH low latency in FFmpeg
Open-source developer Jean-Baptiste Kempf who is well known for his work on VLC discusses his work writing an MPEG-DASH implementation for FFmpeg called the DASH-LL. He explains how it works and who to use it with examples. You can copy and paste the examples from the pdf of his talk.

Managing multi-DRM with DASH
The final talk, ahead of Q&A is from NAGRA discussing the use of DRM within MPEG-DASH. MPEG-DASH uses Common Encryption (CENC) which allows the DASH protocol to use more than one DRM scheme and is typically seen to allow the use of ‘FairPlay’, ‘Widevine’ and ‘PlayReady’ encryption schemes on a single stream dependent on the OS of the receiver. There is complexity in having a single server which can talk to and negotiate signing licences with multiple DRM services which is the difficulty that Lauren Piron discusses in this final talk before the Q&A led by Ericsson’s VP of international standards, Per Fröjdh.

Watch now!
Speakers

Thomas Stockhammer Thomas Stockhammer
Director of Technical Standards,
Qualcomm
Will Law Will Law
Chief Architect,
Akamai
Zachary Cava Zachary Cava
Software Architect,
Hulu
Ali C. Begen Ali C. Begen
Technical Consultant, Video Architecture, Strategy and Technology group,
Comcast
Jean-Baptiste Kempf Jean-Baptiste Kempf
President & Lead VLC Developer
VideoLAN
Laurent Piron Laurent Piron
Principal Solution Architect
NAGRA
Per Fröjdh Moderator: Per Fröjdh
VP International Standards,
Ericsson

Video: Multicast ABR

Multicast ABR is a mix of two very beneficial technologies which are seldom seen together. ABR – Adaptive Bitrate – allows a player to change the bitrate of the video and audio that it’s playing to adapt to changing network conditions. Multicast is a network technology which efficiently sends a video stream over the network without duplicating bandwidth.

ABR has traditionally been deployed for chunk-based video like HLS where each client downloads its own copy of the video in blocks of several seconds in length. This means that you bandwidth you use to distribute your video increases by one thousand times if 1000 people play your video.

Multicast works with live streams, not chunks, but allows the bandwidth use for 1000 players to increase – in the best case – by 0%.

Here, the panelists look at the benefits of combining multicast distribution of live video with techniques to allow it to change bitrate between different quality streams.

This type of live streaming is actually backwards compatible with old-style STBs since the video sent is a live transport stream, it’s possible to deliver that to a legacy STB using a converter in the house at the same time as delivering a better, more modern delivery to other TVs and devices.

It thus also allows pure-streaming providers to compete with conventional broadcast cable providers and can also result in cost savings in equipment provided but also in bandwidth used.

There’s lots to unpack here, which is why the Streaming Video Alliance have put together this panel of experts.

Watch now and find out more!

Speakers

Phillipe Carol Phillipe Carol
Senior Product Manager,
Anevia
Neil Geary Neil Geary
Technical Strategy Consultant,
Liberty Global
Brian Stevenson Brian Stevenson
VP of Ecosystem Strategy & Partnerships,
Ericsson
Mark Fisher Mark Fisher
VP of Marketing & Business Development,
Qwilt
Jason Thibeault Jason Thibeault
Executive Director,
Streaming Video Alliance

Video: SCTE Summer Lecture 2018 – 5G Fixed Wireless Access Study

Ericsson’s Netherlands CTO, Jeroen Buijis talks us about the past, present and future of 5G. With an increasing number of operators wanting to deploy OTT/IPTV solutions to homes using wireless technologies and with cities increasingly densely populated, 5G is seen as a key way to enhance services and internet access in both urban and rural areas.

Covering the pros and cons of different network delivery technologies, this talk goes on to cover
This talk covers:

  • Spectrum use,
  • How available bandwidth relates to video streaming use
  • Indoor reception of 5G
  • Ways in which coverage is maximised
  • A real-world study of wireless access study

Plus much more!

 

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Meeting: Are Existing Broadcast Formats Suitable for HDR WCG Content?


Date: Thursday November 30, 2017 – Ample Refreshments from 18:15 GMT for 19:00 start.
Location: Ericsson Television, Strategic Park, Comines Way, Hedge End, Southampton, SO30 4DA. Google Maps

With higher resolution, wider colour gamut and extended dynamic range, the new Ultra High Definition TV (UHD) standards define a container which allows content creators to offer the consumer a much more immersive visual experience. However there are some artefacts noted within the container particularly around HDR material. Olie Bauman outlines why YCrCb are used and the human vision systems response to changes in chroma/luminance and the correlation between R, G and B

As HDR and WCG expand the Colour Volumes he will show why these increased from SD (601) to HD (709) to UHD (2020) and show the difference between PQ (Display Referred) and HLG (Scene Referred) workflows

From this background he will show examples of artefacts due to chroma down-sampling and show the different characteristics – depending on work flow.

He highlights that the problems will become greater as more content exploiting the full UHD container becomes available, requiring additional care and processing in content production and delivery.

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