Opus in Matroska audio
Opus audio in an MKA file, with the start-up delay every Opus stream carries.
How it should play
What a broken player shows
What goes wrong
The delay is ignored: the start is cut, or the timing is a few milliseconds off.
The file
- Container
- Matroska audio, 6.008 s
- Size
- 127 kB
- Audio
- Opus, stereo, 48,000 Hz
- Expected
- plays correctly in any player
How it was verified
Built by the testsrc generator (gen v0.2) and verified with FFmpeg 7.1.5-0+deb13u1 and GStreamer 1.26.2 in snapshot 2026-11-02, before it was published: the file has the property this page describes, and decoding it gives the expected result.
With a token: the file, how exactly it was built, the full fact sheet, and the expected result the checker judges a player against.
Use it
# the public facts curl https://testsrc.com/v1/cases/edge/mka-opus-codec-delay.mka # the full fact sheet and the file, with your token curl -H "Authorization: Bearer $TESTSRC_TOKEN" \ https://testsrc.com/v1/cases/edge/mka-opus-codec-delay.mka/facts curl -H "Authorization: Bearer $TESTSRC_TOKEN" -o mka-opus-codec-delay.mka \ https://testsrc.com/v1/files/edge/mka-opus-codec-delay.mka # play it through your player and check what it showed testsrc run --player libvlc edge/mka-opus-codec-delay.mka
See the API reference for tokens, quotas and snapshots.
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Get early accessMore on timing and sync
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- MPEG-TS timestamps wrapping aroundMPEG-TSPlayback freezes, jumps or stops at the wrap, and the duration comes out wrong.
- MPEG-TS that doesn't start at zeroMPEG-TSThe duration shows as zero or nonsense, and the seek bar is unusable.
5 more cases on this with a token.