When it comes to IP, audio has always been ahead of video. Whilst audio often makes up for it in scale, its relatively low bandwidth requirements meant computing was up to the task of audio-over-IP long before uncompressed video-over-IP. Despite the early lead, audio-over-IP isn’t necessarily trivial. However, this talk aims to give you a heads up to the main hurdles so you can address them right from the beginning.
Matt Ward, Head of Video for UK-based Jigsaw24, starts this talk revising the reasons to go audio over IP (AoIP). The benefits vary for each company. For some, reducing cabling is a benefit, many are hoping it will be cheaper, for others achievable scale is key. Matt’s quick to point out the drawbacks we should be cautious of, not least of which are complexity and skill gaps.
Matt fast-tracks us to better installations by hitting a list of easy wins some of which are basic, but a disproportionately important as the project continues i.e. naming paths and devices and having IP addresses in logical groups. Others are more nuanced like ensuring cable performance. For CAT6 cabling, it’s easy to get companies to test each of your cables to ensure the cable and all terminations are still working at peak performance.
Planning your timing system is highlighted as next on the road to success with smaller facilities more susceptible to problems if they only have one clock. But any facility has to be carefully considered and Matt points out that the Best Master Clock Algorithm (BMCA).
Network considerations are the final stop on the tour, underlining that audio doesn’t have to run in its own network as long as QoS is used to maintain performance. Matt details his reasons to keep Spanning Tree Protocol off, unless you explicitly know that you need it on. The talk finishes by discussing multicast distribution and IGMP snooping.
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.