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LibMedia: Remove forced seeks upon errors from Matroska::Reader

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This shouldn't actually be necessary, since the sample iterator will
resume from where it hit the error last anyway. Now that the decoded
data producers don't clear their queues when the demuxer doesn't move,
this works just fine for EOF.

This could easily be triggered by scrubbing aborting reads to restart
seeks, which would force us to decode from a prior keyframe instead of
continuing to decode from where the last seek left off if it's faster.
This commit is contained in:
Zaggy1024 2026-05-23 08:33:35 -05:00 committed by Gregory Bertilson
parent 020fe311d8
commit da64588e72
2 changed files with 5 additions and 14 deletions
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11
Libraries/LibMedia/Containers/Matroska/Reader.cpp
View file

@ -709,12 +709,6 @@ static AK::Duration block_timestamp_to_duration(AK::Duration cluster_timestamp,
DecoderErrorOr<Vector<ByteBuffer>> SampleIterator::get_frames(Block block)
{
ArmedScopeGuard error_guard = [&] {
// Similar to next_block(), we need to clear the last timestamp if we encounter an error, or a subsequent
// seek may not move the position to a keyframe to resume decoding properly.
m_last_timestamp.clear();
};
Streamer streamer { m_stream_cursor };
TRY(streamer.seek_to_position(block.data_position()));
Vector<ByteBuffer> frames;
@ -785,7 +779,6 @@ DecoderErrorOr<Vector<ByteBuffer>> SampleIterator::get_frames(Block block)
frames.append(TRY(streamer.read_raw_octets(block.data_size())));
}
error_guard.disarm();
return frames;
}
@ -1206,10 +1199,6 @@ DecoderErrorOr<Block> SampleIterator::next_block()
Streamer streamer { m_stream_cursor };
TRY(streamer.seek_to_position(m_position));
// Remove the last timestamp from this iterator so that if we encounter an error, especially EOS,
// we will always seek the sample iterator, ensuring that we will decode the last block again.
m_last_timestamp = {};
Optional<Block> block;
while (true) {

8
Tests/LibMedia/TestMatroskaDemuxer.cpp
View file

@ -31,7 +31,9 @@ TEST_CASE(seek_past_eos)
EXPECT_EQ(last_timestamp, AK::Duration::from_milliseconds(30126));
auto seek_time = AK::Duration::from_milliseconds(31000);
MUST(demuxer->seek_to_most_recent_keyframe(track, seek_time, Media::DemuxerSeekOptions::None));
auto sample_after_seek = MUST(demuxer->get_next_sample_for_track(track));
EXPECT_EQ(sample_after_seek.timestamp(), AK::Duration::zero());
auto seek_result = MUST(demuxer->seek_to_most_recent_keyframe(track, seek_time, Media::DemuxerSeekOptions::None));
EXPECT_EQ(seek_result, Media::DemuxerSeekResult::KeptCurrentPosition);
auto sample_result_after_seek = demuxer->get_next_sample_for_track(track);
EXPECT(sample_result_after_seek.is_error());
EXPECT_EQ(sample_result_after_seek.error().category(), Media::DecoderErrorCategory::EndOfStream);
}