hi, HA guys,
Working on a MPEG4/DivX decoding project. I happened to think about
a tool: extracting audio stracks in AVI files and save the audio track
to the format as it is (MP3/WMA/OGG, if AC3 maybe transcoding needed).
The extracted audio file can be playback using portable players,
it sounds like OST from movies.

Would you please share with me your comments on:
1) is there any tool like what I described above available?
(VirtualDub can extract audio and save to wav--Windows ACM)
2) If answer to 1) is No. Is this tool needed by people?

Your reading/comments are greatly appreciated!

--sospee

When I need to extract an audio stream from AVI, I use avi2wav
http://agrgic.tripod.com/avi2wav/

If I need the raw stream (MP3, AC3, etc.), I use riffstrip
http://mark0.ngi.it/soft-riffstrip-e.html

VirtualdubMOD is very good too for that...

virtualdubmod can extract some audio formats (mp3, ac3) already (not decoding to .wav needed as in virtualdub)

i dunno how it handles wma, i dont use such crap formats
also i am not sure if its possible to mux wma9 and wma9 pro into .avi already

in any way its not possible to mux ogg vorbis into .avi in a stable/correctly working atm

I have always just used Virtualdub "save wav" feature and then just adjusted the file extension.

This works for mp3 for sure.

AVI-Mux_GUI by Gabest (i think) can extract the audio from an AVI pretty easily in what i think is its native form. Works on Mp3's anyway, i know that it can mux AC3's so maybe it can demux them too

the "save wav" option in virtualdub doesn't actually save a wav at all. it extracts the audio in it's native format.

by Alexnoe, not Gabest --> http://www-user.tu-chemnitz.de/~noe/Video-.../index-eng.html

Save wav will extract in wav format if full prrocessing mode for audio is enabled in Virtualdub.

Note that this function is buggy in Virtualdub Mod. The audio cuts off about 30 minutes into the avi. However, Virtualdub Mod allows a demux which extracts the audio as mp3, mp2, ogg, ac3 or whatever.

From there besweet and ac3machine can be used to create an ac3 soundtrack.

Most of the tools for converting avi to mpeg2 video will only do layer 2 audio compression. This is not within the standard for a NTSC DVD. However, most recent DVD players will play such noncompliant NTSC DVD's with a layer 2 soundtack.

Just remember, you are transcoding, so there will be quality losses in both audio and video.

VirtualDubMod will extract pretty much anything that can be put into AVI normally. Using save wav in vanilla virtualdub will result in RIFF headers and cannot be simply renamed to .mp3 or .ac3 - to be a true raw stream these must be removed with besplit or the tool rjamorim mentioned.

If transcoding is desired, besweet has an AVI input mode - no extraction required .

Graphedit can probably do it as well. I remember having used it for demuxing OGM files on several occasions.

yes, but if you use 'direct stream copy' save wav will extract the stream, then you can just rename the file to mp3 or ac3.

-andy-

Oops was looking for that link!

You can also do this with avi/mkv files. You need the dump-filter, which can be downloaded here (Get All needed filters here).
Then you connect file source async -> whatever demuxer/splitter you need -> dump.

Right. But it still writes the file as .wav so you have to change the file extension to whatever.

Maybe I don't have the latest version?

I believe according to the DVD specs (e.g. http://www.dvdrhelp.com/dvd) MP2 audio is perfectly legal, but only in addition to PCM or AC3.

hi, there,
Thanks for your comments.
I did get sth. I tried some tools before, there's
no one acts as I described: extracting audio data
in AVI (DivX/MPEG4) and save it to MP3 that
can be used in portable players.
Any way, your words are instructive. I'll explore more
online to find out if this kind of tool is really needed.
//bow

--sospee