MPEG DASH is a standardised method for encapsulating media for streaming similar to Apple’s HLS. Based on TCP, MPEG DASH is a widely compatible way of streaming video and other media over the internet.
MPEG DASH is now on its 3rd edition, its first standard being in 2011. So this talk starts by explaining what’s new as of July 2019 in this edition. Furthermore, there are amendments already worked on which are soon to add more features.
Iraj Sodagar explains Service Descriptors which will be coming that allow the server to encapsulate metadata for the player which describes how the publisher intended to show the media. Maximum and minimum latency and quality is specified. for instance. The talk explains how these are used and why they are useful.
Another powerful metadata feature is the Initialization Set, Group and Presentation which gives the decoder a ‘heads up’ on what the next media will need in terms of playback. This allows the player to politely decline to play the media if it can’t display it. For instance, if a decoder doesn’t supply AV1, this can be identified before needing to attempt a decode or download a chunk.
Iraj then explains what will be in the 4th edition including the above, signalling leap seconds and much more. This should be published over the next few months.
Amendement 1 is working towards a more accurate timing model of events and defining a specific DASH profile for CMAF (the low-latency streaming technology based on DASH) which Iraj explains in detail.
Finishing off with session based DASH operations, a look over the DASH workplan/roadmap, ad insertion, event and timed metadata processing, this is a great, detailed look at the DASH of today and of 2020.
Life used to be simple; you’d fire up your camera, point it at a presenter and it would be fed to the transmitter network. When on-going funding came into play, we wanted each transmitter to be able to show local ads and so, after many years, SCTE-35 was born to do exactly that. In today’s world, however, simply telling a transmitter when to switch doesn’t cut it. To deliver the complex workflows that both linear and OTT delivery demand, SCTE 224 has arrived on the scene which provides very comprehensive scheduling and switching.
Jean Macher, from Harmonic explains this needs for SCTE 224 and what it delivers. For instance, a lot for 224 is devoted to controlling the US-style blackouts where viewers close to a sports game can’t watch the game live. Whilst this is relatively easy to deal with in the US for local terrestrial transmitters, in OTT, this is a new ability. Traditionally, geo-location of IP addresses is needed for this to work where each IP address is registered against a provider. If this provider is Chinese, then at the very least, you should be able to say that this IP address is in China. However, for ISPs who have an interest in the programming, they can bring in to effect their own data in order to have very accurate geo-location data.
SCTE 224, however, isn’t just able blackouts. It also transmits accurate, multi-level, schedule information which helps scheduling complex ad breaks providing detailed, frame accurate, local ad insertion.
It shouldn’t be thought that SCTE 35 and SCTE 224 are mutually exclusive. SCTE 35 can provide very accurate updates to unscheduled programmes and delays, where the 224 information still carries the rich metadata.
To finish up the talk, Jean looks at a specific example of the implementation and how SCTE 224 has been updated in recent years.
SCTE-35 has been used for a long time in TV to signal ad break insertions and other events and in recent years has been evolved into SCTE-104 and SCTE-224. But how can SCTE-35 be used in live OTT and what are the applications?
The talk starts with a look at what SCTE is and what SCTE-35 does – namely digital program insertion. Then the talk moves on to discuss the most well-known, and the original, use case of local ad insertion. This use case is due to the fact that ads are sold nationally and locally so whereas the national ads can be played from the playout centre, the local ads need to be inserted closer to the local transmitter.
Alex Zambelli, Principal Product Manager at Hulu, then explains the message format in SCTE along with the commands and descriptors giving us an idea of what type of information can be sent and how it might be structured. Looking then to applying this to OTT, Alex continues to look at SCTE-224 which defines how to signal SCTE-35 in DASH.
For those who still use HLS rather than DASH, Alex looks at a couple of different ways of using this with Apple, perhaps unsurprisingly, preferring a method different from the one recommended by SCTE.
The talk finishes with a discussion of the challenges of using SCTE in OTT applications. See the slides
Whether it’s to thwart ad blockers or to compensate for unreliable players, server-side ad insertion (SSAI) has an important role for many ad-based services. Phil Cluff is here to look at today’s difficulties and to look into the future.
Talking at the August Seattle Video Tech meet up, Phil looks at how we got where we are and why SSAI came about in the first place. He then looks at the manifest-manipulation method of doing this before seeing how well OTT devices actually support it showing inconsistent support for DRM in DASH and HLS. Smart TVs are a big problem delivering consistent viewing with all being different and even the new ones being delivered into the market now are few compared to the older, 5+ year-old TVs.
One solution to levelling the playing field is to distribute Chromecasts which works fairly well in allowing any device to be come a streaming device. Another option is to use server-side sitting SSAI meaning the video stream itself has the advert in it. One problem with this approach is the impracticality to target individual users. HbbTV and ATSC 3.0 are other ways to deliver adverts to the television.
Beacons are a way of players singling back to the ad networks that adverts were actually shown so Phil takes a look at how these will change as time moves on before opening up to questions from the floor.