Iraj Sodagar Archives – The Broadcast Knowledge

Video: Overview of MPEG’s Network-Based Media Processing

Posted on 18th March 2021 by Russell Trafford-Jones

Building complex services from microservices not simple. While making a static workflow can be practical, though time-consuming, making one that is able to be easily changed to match a business’s changing needs is another matter. If an abstraction layer could be placed over the top of the microservices themselves, that would allow people to concentrate on making the workflow correct and leave the abstraction layer to orchestrate the microservices below. This is what MPEG’s Network-Based Media Processing (NBMP) standard achieves.

Developed to counteract the fragmentation in cloud and single-vendor deployments, NBMP delivers a unified way to describe a workflow with the platform controlled below. Iraj Sodagar spoke at Mile High Video 2020 to introduce NBMP, now published as ISO/IEC 23090-8. NBMP provides a framework that allows you to deploy and control media processing using existing building blocks called functions fed by sources and sinks, also known as inputs and outputs. A Workflow Manager process is used to actually start and control the media processing, fed with a workflow description that describes the processing wanted as well as the I/O formats to use. This is complemented by a Function Discovery API and a Function Repository to discover and get hold of the functions needed. The Workflow Manager gets the function and uses the Task API to initiate the processing of media. The Workflow Manager also deals with finding storage and understanding networking.

Next, Iraj takes us through the framework APIs which allow the abstraction layer to operate, in principle, across multiple cloud providers. The standard contains 3 APIs: Workflow, Task & Function. The APIs use a CRUD architecture each having ‘update’ ‘Discover’ ‘Delete’ and similar actions which apply to Tasks, Functions and the workflows i.e. CreateWorkflow. The APIs can operate synchronously or asynchronously.

Split rendering is possible by splitting up the workflow into sub workflows which allows you to run certain tasks nearer to certain resources, say storage, or in certain locations like in the case of edge computing where you want to maintain low-latency by processing close to the user. In fact, NBMP has been created with a view to being able to be used by 5G operators and is the subject of two study items in 3GPP.

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Speaker

Iraj Sodagar
Principal Researcher
Tencent America

Iraj Sodagar,
Tencent America

Video: DASH Updates

Posted on 17th October 2019 by Russell Trafford-Jones

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.

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Speaker

Iraj Sodagar
Independant Consultant

Video: Using CMAF to Cut Costs, Simplify Workflows & Reduce Latency

Posted on 5th March 2019 by Russell Trafford-Jones

There are two ways to stream video online, either pushing from the server to the device like WebRTC, MPEG transport streams and similar technologies, or allowing the receiving device to request chunks of the stream which is how the majority of internet streaming is done – using HLS and similar formats.

Chunk-based streaming is generally seen as more scalable of these two methods but suffers extra latency due to buffering several chunks each of which can represent between 1 and, typically, 10 seconds of video.

CMAF is one technology here to change that by allowing players to buffer less video. How does this achieve this? An, perhaps more important, can it really cut costs? Iraj Sodagar from NexTreams is here to explain how in this talk from Streaming Media West, 2018.