[FFmpeg-trac] #8443(undetermined:new): A/V drift when reencoding NTSC
FFmpeg
trac at avcodec.org
Thu Dec 26 18:47:07 EET 2019
#8443: A/V drift when reencoding NTSC
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Reporter: | Owner:
madscientist159 |
Type: defect | Status: new
Priority: normal | Component:
| undetermined
Version: unspecified | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by madscientist159):
Yes, I understand now that showwaves is not going to be able to help
diagnose the other A/V sync issue due to this bug. I'm still searching
for an alternate method to view per-frame A/V sync using open source
software, without much luck so far.
kdenlive apparently uses ffmpeg for its audio waveform display, and is
very much affected by the same bug. This also added some confusion.
The live streaming bug manifests as a desync of several hundred ms over a
few hours, and is not practical to debug until a reliable way is found to
measure the small (one or two ms) desync that would occur over a much
shorter period of time. I have an initial hardware method to detect the
output sync within some hundreds of microseconds accuracy, but since I
cannot measure the *input* file A/V sync (yet) I am kind of stuck.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8443#comment:6>
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