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28 lines
1.3 KiB
28 lines
1.3 KiB
4 years ago
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Audio-Video out of sync after merging encoded DV or VOB clips?
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There is a fundamental problem when merging AVI-files with MP3 sound, that
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have been transcoded individually. As far as I know, it needs a certain
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amount of raw PCM data to make a single MP3 encoded frame. At the end of the
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encoding process, this condition is almost never fulfilled. Therefore,
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some audio data are simply not encoded, or, using option -O,
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PCM data (silence) are padded to make a final MP3 frame. In the former case,
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sound is too short in time, whereas in the latter, the audio played
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by a player exceeds the video playtime. This may be only a couple
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milliseconds but adds up when merging the clips.
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Why does it work for transcode using option "-t" or DVD chapter mode "-U" ?
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In this case, the MP3 encoder is never switched off. Buffered audio data
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never get lost. After merging, audio and video are OK (in theory).
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This is also the reason, why the cluster mode must use this approach encoding
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the audio in a separate step, unless you want to use raw PCM audio data.
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Now what to do with tons of DV AVI-file clips, you want to merge, but
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only after encoding?
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The "directory mode" with option "-i" also works for DV AVI-files (hopefully).
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Try to put all clips into a directory and use the directory name
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to let transcode extract and merge the raw DV stream for further processing.
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