[FFmpeg-devel] [PATCH 5/6] avcodec/qtrle: return last frame even if unchanged

[Kieran Kunhya]

>
>
> Lets check H264
> claim "They do not have a timestamp"
> immedeatly after the pic_struct field which tells you about the repeating
> behavior there is a loop for each repeated value with a timestamp.
> This timestamp is lost, if at CFR one can call it that way.
>
> about "Every encoded frame should produce a decoded frame"
> quote about this timestamp from the h264 spec
> "The contents of the clock timestamp syntax elements indicate a time of
> origin, capture, or alternative ideal display."
>

This is a simple misunderstanding of the difference between timecode and
timestamp.
I point you to numerous publications about the difference.


> "origin, capture" implies that the repeated frame can have come from
> a real input packet because otherwise it wouldnt have a capture or origin
> time.
> So an encoder could use this as a way to represent some input frames
> And in that case only a decoder that follows these repeats exactly would
> have input == output
> which again brings us full circle as this matches what we see in qtrle
> repeats
>

You conflate presentation (with repeated fields/frame) and decoding which
are not the same thing.

Kieran