Extract the audio out of MJPEG container files to stdout
see also :
mp2enc - sox
[-s num] [-c num]
[-v num] [-I]
[-R] [-r samplerate, bitesize,
channels] lavfile1 [lavfile2 ...
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can be used to extract the audio to stdout. This output goes
to stdout and can be saved as a wav file or piped to another
sound processing tool that is able to handle the wav format.
This can be mp2enc and toolame for mpeg layer 2 audio, or
for example lame for mpeg layer 3 audio.
The input files
may be any combination of AVI (.avi), Quicktime (.qt) or
editlist files so long as they are all lavtools-
readable (e.g. MJPEG-encoded AVI/Quicktime or DV type 2
accepts the following options:
Start extracting at video frame
Extract (num) frames of
Verbosity level (0, 1 or 2)
Ignore unsupported bitrates/bits per sample
If the file does not contain any sound. lav2wav will
create silence with 44100kHz Sampelrate, 16 Bit audio
bitsize and 2 Chanels
If the file does not contain
any sound lav2wav will generate silence with the values you
supply the samplerate (sr), audio-bitsize (bs) and channel
"WAV" file format (technically: RIFF) is really
very much less than ideal for a tool intended to be used in
pipelines as lav2wav is. The problem is that the header
includes a field specifying the length of the file. This
can’t be filled in except by seeking back to the
begining and over-writing. If the output is unseekable (e.g.
pipe) lav2wav simply writes a large length into the header
and leaves it at that. Most tools like sox(1) or mp2enc(1)
either ignore the length field anyway or only give a
The audio length is inacurate calculated when lav2wav
generates silence. This happens only if you have NTSC
framerate and than it creates for every hour of video
1.1498sec too less of silence.
mp2enc , sox
This man page
was written by Bernhard Praschinger.
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