[FFmpeg-devel] [PATCH] Don't adjust start time for MP3 files; packets are not adjusted.

[Dale Curtis]

Ping for this patch. Thanks

- dale

On Thu, Apr 23, 2020 at 4:33 PM Dale Curtis <dalecurtis at chromium.org> wrote:

> This is a patch Chromium has carried for a while, we forgot to send it
> upstream. 7546ac2fee4 made it so that the start_time for mp3 files is
> adjusted for skip_samples. However, this appears incorrect because
> subsequent packet timestamps are not adjusted and skip_samples are
> applied by deleting data from a packet without changing the timestamp.
>
> E.g., we are told the start_time is ~25ms and we get a packet with a
> timestamp of 0 that has had the skip_samples discarded from it. As such
> rendering engines may incorrectly discard everything prior to the
> 25ms thinking that is where playback should officially start. Since the
> samples were deleted without adjusting timestamps though, the true
> start_time is still 0.
>
> Other formats like MP4 with edit lists will adjust both the start
> time and the timestamps of subsequent packets to avoid this issue.
>
> Signed-off-by: Dale Curtis <dalecurtis at chromium.org>
>