问题
I have a MKV file with gaps in the audio. That is, there are gaps in the MKV audio track timestamps. According to "ffmpeg", the AC3 audio length is 802 seconds, but when exporting the audio to WAV, the resulting file length is 801'53 seconds. That is, the "exported" audio is shorter.
Triaging the issue with
ffmpeg -i INPUT.mkv -af ashowinfo -map 0:2 -y -frames:a XXXX -f alaw /dev/null
I can confirm that the length difference is consistent with gaps in the timestamps of the original audio frames. There are a handful of missing audio frames. I guess those are replaced by silence in the player.
The command I use to export the audio is:
ffmpeg -i INPUT.mkv -map 0:1 -ac 2 OUTPUT.wav
My question is: How can I instruct FFMPEG to preserve the gaps in the original audio, zero (silence) filled?. The WAV file duration should be the same than the original AC3 audio.
Given my current workflow, I would rather prefer to not keep the original timestamps in the output file but generate a WAV with (tiny) silences instead. I could consider keeping timestamps if there is no other choice, but this could be quite a pain in my workflow.
Advice? Help?
Thanks a lot in advance!
回答1:
Use
ffmpeg -i INPUT.mkv -map 0:1 -af aresample=async=1 -ac 2 OUTPUT.wav
The aresample filter will insert silent samples within the gaps.
来源：https://stackoverflow.com/questions/52845150/use-ffmpeg-to-export-audios-with-gaps-filled