ffmpeg now fails to see audio stream
So when I re-code a DVD, I use mencoder to handle the video part and ffmpeg to handle the audio (including mixing 5:1 down to stereo). The reason for the latter is in all the years I've tried, I've never figured out how to get mencoder to extract mix and write just audio.
Got a new DVD. vobcopied it. Identified which VOBs are the one I want. Ran a script to recode just the video part. Nothing new there. Do this all the time. Familiar. No problems. Did not expect any. Problem: I ran my usual command options with ffmpeg to get audio and ... ffmpeg claims there is no audio stream. That's a new one. And yet somehow ffplay plays the files fine, with sound. Contradiction. The relevant section of my script (which has worked for ages): Code:
cat \ Ran mplayer just to see what streams it saw. Hmm, 0x80, 0x81, 0x82, 0x83, yup: four audio streams, named (well, numbered) as usual. Consultation of the manual reveals that maybe the syntax for ffmpeg's "-map" has changed. Right, so I say "-map 0:0" or even "-map 0:a:0" now? OK, whatever. I make the change. Nope. Still fails. Sigh. Right: two questions. One: how to accomplish the following ... Quote:
Failing that, question two: If mencoder can do this, how? I've never been able to figure this out over several years Thank you. |
I don't know if mencoder will extract audio directly from a DVD. But it will from a video file, such as avi or mpg. I don'[t know the exact command line off the top of my head. But try ripping the mpg off the DVD and then get the audio off that.
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Dobbs what has changed ? Put a pipe in it and see the DIFF
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So after giving up (six months ago) I returned to the problem.
First step: although ffmpeg programs all fail to recognize nor play the audio, ffplay at least indicates that there is audio, in the form of AAC, but zero channels. There is no such thing as audio with zero chaannels, so that' s some indication of the problem. Maybe it is the interleaving of the audio with the video that is funky. So we break the processing of the audio into two tasks. First task, seperate the audio out, as-is. The raw audio codec data, all by itself in a different container, may work with fflay/ffmpeg. So how to get that? Various search engines, docs, and Trial & error resulted in a way to get that audio out using mencoder: Code:
cat /hsc/vobcopy_temp/$MOVHERE/VIDEO_TS/VTS_07_[1-7].VOB | \ Turns out that, once the audio was all by itself, suddenly ffplay, and thus ffmpeg, would read it. Great. The audio was in six channel form. No problem, many DVDs use this and that is familiar ground: Code:
ffmpeg \ That worked. From then on, usual conversion to a compressed format and remuxing with the video. |
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