2012年4月18日1:12 Derek Buitenhuis <[email protected]>:

> On 16/04/2012 10:52 AM, Yusuke Nakamura wrote:
> > The second patch may deny
> http://git.libav.org/?p=libav.git;a=commit;f=libavformat/mov.c;h=26846ba5151b0fe90e21c1a6beb9a3bcb569d1ac,
>  while this commit denies splitted files with gradual decoder refresh (not
> marked as a sync sample in 14496-15 spec).
> > So, I prefer the second patch to this commit.
>
> The first patch looks reasonable to me, but I'm unsure of
> whether the second patch is a good idea or not -- key_off
> will always end up being 1, even if sc->keyframes[0] and/or
> sc->stps_data[0] are > 1. Seems like it could break things
> or have unintended consequences. Perhaps someone more
> familiar with mov.c could comment.
>
> - Derek
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The gist of the second patch is supporting for AVC-in-MP4 starting at frame
with recovery point SEI.
14496-15 defines type of frame that can be a sync sample is only IDR, i.e.
a random accessible frame that is such as open-gop I-frame and/or any frame
that is a starting point of certain GDR are not marked as a sync sample.
In this case, obviously stss indexes of the file doesn't start at 1, and
without this patch libavformat won't set up keyframe (IDR-frame) positions
correctly.
So, the focus of the problem is whether we continue to support non-spec
compliant files (0-origin indexes), or discard them and support
spec-compliant files that contain incomplete frames early.

Does anyone have more comments?
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