I noticed in many sample mp4 clips (with hevc stream generated using x265), that CRA frames do not get indexed by mp4 as keyframes. Can the experts confirm if this is intentional/design? Is there an option to tell mp4box to mark them as keyframes
In HEVC syntax, CRA are clean random access I-frames, hence they are valid random access sync points.
It would be great if mp4box would mark them as key-frames, since I would expect x265+mp4box will be extremely popular combination for autoring hevc content for streaming/broadcast etc.
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Yes, CRA should be marked as sync samples, possibly with a 'rap ' or 'sync' sample group indicating the sample is a CRA. We will fix it asap. Thanks for the report.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I noticed in many sample mp4 clips (with hevc stream generated using x265), that CRA frames do not get indexed by mp4 as keyframes. Can the experts confirm if this is intentional/design? Is there an option to tell mp4box to mark them as keyframes
In HEVC syntax, CRA are clean random access I-frames, hence they are valid random access sync points.
It would be great if mp4box would mark them as key-frames, since I would expect x265+mp4box will be extremely popular combination for autoring hevc content for streaming/broadcast etc.
Yes, CRA should be marked as sync samples, possibly with a 'rap ' or 'sync' sample group indicating the sample is a CRA. We will fix it asap. Thanks for the report.
See my answer on github: https://github.com/gpac/gpac/issues/144
Awesome! Thanks folks for your prompt response and for fixing this.