Switching set using single initialization constraints (CTA WAVE Test content)

[haudiobe]

The issue originates from the CTA WAVE Test Content generation and is discussed here:

https://github.com/cta-wave/Test-Content/issues/43

While we do not expect that this issue discusses what test content needs to be generated, it would be good to get feedback on the following:

Is it correct that the following 3 Initialization switching use cases exist?

• Single/common CMAF Header (w/ sample entry for each track i.e. multiple sample entries) + fragments without in-band parameter sets (avc1).
• Single/common CMAF Header (without parameter sets) + fragments with in-band parameter sets (avc3).
• Multiple CMAF Headers (with sample entry, 1 for each track) + fragments without parameter sets (avc1).

Questions:

• Are these correct?
• Are there any additional ones?
• Which ones have priority in order to properly generate test content

[cconcolato]

For the first case "Single/common CMAF Header (w/ sample entry for each track i.e. multiple sample entries) + fragments without in-band parameter sets (avc1).", it needs also to use different "sample description index" values in the samples. To my knowledge, support for that in players is not widespread (I may be wrong).

[haudiobe]

No impact on CMAF spec for now. Keep it open for one more cycle, want to check in context with the test vector generation in CTA WAVE.

[RufaelDev]

Question is this also an option in some configurations also considered ?

Single/common CMAF Header (with parameter sets) + fragments with in-band parameter sets (avc3).

[krasimirkolarov]

We want to encourage creating test vectors that exercises all these options (perhaps Romain?). Perhaps we should also document what are the use cases for those.

[cconcolato]

We also need to consider encryption, as having multiple keys can multiply the number of entries.

[krasimirkolarov]

the topic was included in the 2nd version of the CMAF-IF survey and we expect responses in the next couple of months.