CTA-WAVE/SVTA Streaming Media Tracing Standards

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Project Status:

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Write

The working group is currently writing the document. This is a collaborative approach using Google Docs.

Start:

March 31, 2022

Estimated Completion:

January 1, 2024
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Problem Statement

The Streaming Media Tracing Working Group in CTA-Wave will seek to improve streaming media observability and quality of experience by developing standards for media object request tracing, content creation and propagation, media object transformation, and related telemetry data export.

Project Description

Streaming media technologies are widespread and a significant area of growth for modern networks, both Internet-wide and on smaller networks. Likewise, modern media transportation technologies involve an increasing number of participating entities like Content Delivery Networks (CDNs), transcoders, packagers, or content routers. The number and kind of participants in the streaming media transport chain is likely to continue to grow as new technologies are developed and deployed.   As streaming media transits this complex and diverse distributed system, errors, delays, and other impediments to delivery are inevitable. The identification of and correct attribution for these events is a vital step in both short-term remediation and long-term prevention of delivery impediments that reduce the quality of the experience the ultimate consumer of the media receives.   The goal of the Streaming Media Tracing Working Group is to create a standard mechanism or set of mechanisms by which these delivery impediments can be quickly and efficiently identified. These mechanisms should be usable by as many participants in the delivery system as is technically feasible, without requiring after-the-fact cooperation between entities.   Not all delivery impediments can be adequately identified exclusively through information carried in-band with media requests and responses, so a second goal is to create a standard mechanism by which this information can be exported to an entity suitable for collecting it.   In the context of this Working Group, media is considered to include any information that represents human sensory information like visual or auditory data. Streaming media, then, in this context, is media that changes dynamically and sequentially over time and is consumed over a similar period of time, like a movie or audiobook. Non-streaming media does not change over time, like an image or the text of a book.

Project Type

Document

Project Leads

Project leads have not yet been identified.

Advisors

There are no SMEs associated with this project.

Goals and Objectives

The Streaming Media Tracing working group will systematically define the following standards:

Request Tracing

The request tracing specification seeks to address observability gaps in the delivery of real-time streaming media experiences, over HTTP, across content providers and third party services. Request tracing spans the spectrum of HTTP requests made by client applications and other services on the client’s behalf. The specification takes into consideration modern streaming media delivery protocols and conventions in addition to complex request flows such as 304 redirects and CDN request collapsing. To this end, in contrast to other tracing specifications and conventions, this specification will organize information based on the set of requests required to fulfill a single intent (e.g. retrieval of a single media from one or more CDNs).

Content Creation and Propagation

The Content Creation and Propagation specification will seek to address observability gaps for the online and offline creation processes for both live and VOD scenarios. This includes ingest from live sources or mezzanine source files followed by various workflow stages such as encoding, transcoding to multiple bitrates, dynamic ad stitching (SSAI), encryption, etc. This specification is meant to work in tandem with the Request Tracing specification to provide both enhanced observability for the requesting of media objects and related data from media applications and the creation, propagation and staging of media objects in order to fulfill those requests either offline or in real time.

Trace Telemetry Export

While the two specifications above will seek to propagate data in-band, leveraging HTTP headers or querystrings, there are scenarios where trace data must be delivered from workflow sources to centralized storage and analysis services. For instance, if a media object request is made by a video player and that request times out only out-of-band logging to centralized services will support proper root cause analysis.The Trace Telemetry Export specification will seek to close this gap by defining the information useful to the identification of impediments.

Cross-cutting Support for Object Transformation Tracing

In order to enable the tracing of media object defects (rather than impediments to the delivery of those objects) the three specifications listed above will seek to include data elements necessary to determine where, when and how each object is modified during creation, propagation, or delivery.

Project Scope

The Streaming Media Tracing Working Group will do the following:
  • Document a standard for transporting information useful to the identification of impediments to the delivery of streaming media in-band with HTTP requests and responses;
  • Document a standard for transporting that same information out-of-band;
  • Document a standard for transporting that same information in-band with streaming media that is driven by a push or broadcast model instead of a request–response model; and
  • Ensure that documents have appropriate designations for public and private data so that entities can easily strip only the private data at their perimeters.
These things may be documented in one or more final documents, as the Working Group deems appropriate. The Working Group will initially consider at least these things to be required for the successful delivery of streaming media:
  • The body of the media itself;
  • Thumbnails, text descriptions, and imagery that serve to represent the media;
  • DRM licenses required to display the media;
  • Metadata that facilitates the transfer or identification of media; and
  • Information that identifies the context around the request, like session or content identifiers.
Likewise, the Working Group will initially consider at least these things to be relevant to the identification of impediments to delivery:
  • Timing information around all requests, responses, processing, and creation of media elements;
  • Storage information that indicates how, where, why, and for how long media elements have been stored;
  • Transformation information that documents how media elements have been modified; and Identity information for all entities that have participated in the delivery of media elements.
The Working Group is free to reconsider the lists of things relevant to the successful delivery of streaming media and the identification of impediments to delivery, adding or subtracting as it finds fit. When documenting standards, the Working Group will ensure that all standards are suitable for streaming media. Where technically reasonable, standards should also be suitable for non-streaming media. And where it can be accomplished without undue effort, standards should be suitable for arbitrary data in general. This will increase the degree to which these standards adapt to unpredictably changing technologies in the future. The Working Group will not:
  • Document standard APIs for programming language implementations;
  • Document specific transports for out-of-band tracing carriage;
  • Prescribe or proscribe particular actions as a consequence of data values;
  • Document a standard for a request–response model that does not use HTTP; or
  • Rely on technologies that are not defined by a standard specification document.
The Working Group will work with existing technologies and emerging technologies and liaise with relevant Working Groups both within the Consumer Technology Association and with other Standards Development Organizations as is appropriate under the relevant charters in order to achieve these ends.

Contributors

The following members have contributed to this project. Click on their name to visit their profile. If they have not published their profile, the link will redirect to their LinkedIn profile.

Additional References

There are no additional references or other required readings need to participate in this project.

Presentations

The following presentations delivered during Measurement/QoE working group sessions may provide additional information about this project.