Hi, when packaging a cmaf video track e.g. mp4Box -dash 1000 -out out.mpd --cmaf=cmfc vvc_8b_bt709-ClosedGOP-3840x2160-24fps-60s-4Mbps.mp4 the mp4 file written is not fullly cmaf compliant namely: 

the stss box absent (cmaf mention this shall be present if not all samples are sync samples which is not the case for this video track) 
tkhd flags shall be 0x000007  (23000-19 9.2) for video tracks , it is set to 3 in my test file.

It would be great if these can be fixed to improve the CMAF compliance, thank you


cmaf video track compliance tkhd/stss
This is a GitHub Issue
repo:gpac
owner:gpac
Title : cmaf video track compliance tkhd/stss
Issue date:

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Hi, when packaging a cmaf video track e.g. mp4Box -dash 1000 -out out.mpd --cmaf=cmfc vvc_8b_bt709-ClosedGOP-3840x2160-24fps-60s-4Mbps.mp4 the mp4 file written is not fullly cmaf compliant namely: 

the stss box absent (cmaf mention this shall be present if not all samples are sync samples which is not the case for this video track) 
tkhd flags shall be 0x000007  (23000-19 9.2) for video tracks , it is set to 3 in my test file.

It would be great if these can be fixed to improve the CMAF compliance, thank you


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The issue describes non-compliance with CMAF (Common Media Application Format) standards in the generated MP4 files, specifically the absence of the stss box and incorrect tkhd flags. However, this does not indicate a security vulnerability but rather a compliance or functionality issue.