| Message ID | 20240514200643.721-1-llyyr.public@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel] avformat/mov: avoid seeking back to 0 on HEVC open GOP files | expand |
| Context | Check | Description |
|---|---|---|
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
On Wed, 15 May 2024 01:36:43 +0530 llyyr.public@gmail.com wrote: > From: llyyr <llyyr.public@gmail.com> > > ab77b878f1 attempted to fix the issue of broken packets being sent to > the decoder by implementing logic that kept attempting to PTS-step > backwards until it reached a valid point, however applying this > heuristic meant that in files that had no valid points (such as HEVC > videos shot on iPhones), we'd seek back to sample 0 on every seek > attempt. This meant that files that were previously seekable, albeit > with some skipped frames, were not seekable at all now. > > Relax this heuristic a bit by giving up on seeking to a valid point if > we've tried a different sample and we still don't have a valid point > to seek to. This may some frames to be skipped on seeking but it's > better than not being able to seek at all in such files. > > Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP > files") Fixes: #10585 > --- > libavformat/mov.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/libavformat/mov.c b/libavformat/mov.c > index b3fa748f27e8..6174a04c3169 100644 > --- a/libavformat/mov.c > +++ b/libavformat/mov.c > @@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext > *s, AVStream *st, int64_t timestamp, { > MOVStreamContext *sc = st->priv_data; > FFStream *const sti = ffstream(st); > - int sample, time_sample, ret; > + int sample, time_sample, ret, next_ts, requested_sample; > unsigned int i; > > // Here we consider timestamp to be PTS, hence try to offset it > so that we @@ -10154,7 +10154,17 @@ static int > mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp, > if (!sample || can_seek_to_key_sample(st, sample, timestamp)) > break; > - timestamp -= FFMAX(sc->min_sample_duration, 1); > + > + next_ts = timestamp - FFMAX(sc->min_sample_duration, 1); > + requested_sample = av_index_search_timestamp(st, next_ts, > flags); + > + // If we've reached a different sample trying to find a good > pts to > + // seek to, give up searching because we'll end up seeking > back to > + // sample 0 on every seek. > + if (!can_seek_to_key_sample(st, requested_sample, next_ts) > && sample != requested_sample) > + break; > + > + timestamp = next_ts; > } > > mov_current_sample_set(sc, sample); LGTM. I know it's been a _long time_ since you first sent this; I'll push next week if there aren't any other comments. --phil
On Tue, 14 May 2024 19:07:59 -0700 Philip Langdale via ffmpeg-devel <ffmpeg-devel@ffmpeg.org> wrote: > On Wed, 15 May 2024 01:36:43 +0530 > llyyr.public@gmail.com wrote: > > > From: llyyr <llyyr.public@gmail.com> > > > > ab77b878f1 attempted to fix the issue of broken packets being sent > > to the decoder by implementing logic that kept attempting to > > PTS-step backwards until it reached a valid point, however applying > > this heuristic meant that in files that had no valid points (such > > as HEVC videos shot on iPhones), we'd seek back to sample 0 on > > every seek attempt. This meant that files that were previously > > seekable, albeit with some skipped frames, were not seekable at all > > now. > > > > Relax this heuristic a bit by giving up on seeking to a valid point > > if we've tried a different sample and we still don't have a valid > > point to seek to. This may some frames to be skipped on seeking but > > it's better than not being able to seek at all in such files. > > > > Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP > > files") Fixes: #10585 > > LGTM. > > I know it's been a _long time_ since you first sent this; I'll push > next week if there aren't any other comments. > Pushed. Thanks! --phil
diff --git a/libavformat/mov.c b/libavformat/mov.c index b3fa748f27e8..6174a04c3169 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp, { MOVStreamContext *sc = st->priv_data; FFStream *const sti = ffstream(st); - int sample, time_sample, ret; + int sample, time_sample, ret, next_ts, requested_sample; unsigned int i; // Here we consider timestamp to be PTS, hence try to offset it so that we @@ -10154,7 +10154,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp, if (!sample || can_seek_to_key_sample(st, sample, timestamp)) break; - timestamp -= FFMAX(sc->min_sample_duration, 1); + + next_ts = timestamp - FFMAX(sc->min_sample_duration, 1); + requested_sample = av_index_search_timestamp(st, next_ts, flags); + + // If we've reached a different sample trying to find a good pts to + // seek to, give up searching because we'll end up seeking back to + // sample 0 on every seek. + if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample) + break; + + timestamp = next_ts; } mov_current_sample_set(sc, sample);
From: llyyr <llyyr.public@gmail.com> ab77b878f1 attempted to fix the issue of broken packets being sent to the decoder by implementing logic that kept attempting to PTS-step backwards until it reached a valid point, however applying this heuristic meant that in files that had no valid points (such as HEVC videos shot on iPhones), we'd seek back to sample 0 on every seek attempt. This meant that files that were previously seekable, albeit with some skipped frames, were not seekable at all now. Relax this heuristic a bit by giving up on seeking to a valid point if we've tried a different sample and we still don't have a valid point to seek to. This may some frames to be skipped on seeking but it's better than not being able to seek at all in such files. Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files") Fixes: #10585 --- libavformat/mov.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)