demux/extract soundtrack from avi

[Twm]

hi

how to extract ac3 stream in avi file??
what app use with ?

aviac3split don t work :-(

[4lex]

never tried it but I would imagine nandub could do it?

[Twm]

don t work too

nandub mixte ac3 into avi if ac3 is separate file to make 1 avi file
not inverse :-(

[sibe]

Nandub definitely does it! Select "Direct stream copy" in the audio menu, then choose "Save WAV" in the file menu and then rename your file to .ac3

I've seen a lot of people getting confused about this, although it says save WAV it actually extracts the audio track in whatever format it is when you checked "Direct stream copy". It will have a .wav ending but you just have to rename it and you're fine.

Sibe

.. sibe is correct, this is the way to do it. If you chose ' "audio.ac3" ' as your filename you may even do the renaming process while its demuxed ...

[Stendrik]

I have made a DivX movie with AC3 sound and then splitted it into two parts.
Now I want to extract the AC3-files from these DivX-files again(doesn't sound logical, I know).
Can anyone tell me how to do this ?

[sibe]

The same question was already answered in this forum. Look at that thread: http://rilanparty.com/vbb/showthread...threadid=11514

[Chaos_rox]

Aiight, so,just like the topic, i need some help extracting AC3 audio from a divx (.avi) file. (i was surprised to, a divx with ac3 audio!?) Anybody have any ideas on what to do?

[dragoman]

Use Virtualdub.

First, load your avi file under the "file" menu.

Go to the audio menu, select both "avi audio" and "direct stream copy".

Then go to file menu, select "Save wav". Ignore the title, and name the file xxxx.ac3

Then click okay.

The program will demux the audio as-is, that is it will extract the ac3 file from the divx to you hard drive.

BTW, I always encode my DivX movies with the ac3 audio from the dvd. Plays back much cleaner, crisper, and surround sound is built in.

dragoman

[Slogra]

I want to re-encode a movie, but i don't want to re-encode the audio. So i want to get the mp3 from the old movie and put it in the new one.

How do i get the mp3 directly from the old avi?

I know this qeustion has been asked before, but i don't remeber the solution.


THANKS!

[DSPguru]

read the AUDIO FAQ.

[Slogra]

Ok, the audio faq didn't really help me much.

But i think i figured it out myself.
I saved the sound to .wav with Nandub. I always thought this would give me a uncompressed wav file, but it's an mp3 with a wav header instead.
I guess i can use this wav file for the new video. Should i import it as .wav or as .mp3 file in Nadub?

[DSPguru]

Originally posted by Slogra
Ok, the audio faq didn't really help me much.

don't you think that this could have HELPED YOU ?

15) How can I extract an AC3 stream from an AVI file with AC3 audio?

This is easy with Nandub.
audio -> direct stream copy
file -> save WAV
rename the resulting file from xxx.wav to xxx.ac3

make sure this is your LAST post regarding issues that had been discussed in the past or appears in the FAQs.
doom9 decided to make sure all users obey the forum rules, and he'll start banning users that don't !

we won't tolerate lazy users.

[Slogra]

Mp3 is not the same as Ac3. So i didn't read this part of the faq.

Sorry...

[gregor7777]

No reason to be so snooty DSPguru, he has a valid point. It doesn't say MP3, so why would one assume that the same process would work? Especially if he didn't know that the process had anything to do with wav's?

Sheesh, I don't think Doom9 had this in mind, the guy was being cool.

I just did a quick search as I had the very same question, I didn't really come up with much until I read this thread.

Now, on to another Q: Is this just a shortcoming of the program? I mean, if the file still consists of a VBR MP3, why does it make a difference what the header says it is? Just curious...

[MaTTeR]

DSPguru snooty? Nah..he's just enforcing the rules. Yes, Doom9 does have this very thing in mind. Were looking for quality posts which indicate people are reading the documents and exploring a little before posting.

The problem is that were seeing to many people that are afraid to point and click a button if the docs/FAQ's don't say to do so exactly down to the letter. Hope this makes sense.

[gregor7777]

@Matter

I understand, and you were clear enough. I know what you mean, as I'm a long standing members at other various tech boards that face the very same problem.

Anyhow, I just thought that DSP was a little curt, where he might not have to have been. I mean the guy did post the resoloution to his own problem, instead of disappearing into nowhere, you know? But you fellows have the way of it, so I'll digress.

Thanks

[LigH]

Dear DSPguru,

if you rant about lazy users, you shall also rant about lazy guides: In fact, it might work to extract the audio to a WAV file, but the resulting file will always have a RIFF-WAVE header when using Nandub/VirtualDub. Therefore, simply renaming the file is indeed wrong. Although it may work in some cases, e.g. many AC3 or MP3 reading applications may ignore the headers and skip to the first valid block; instead, others may not and will fail - due to the additional WAVE header.

For example, the WinDAC archive (currently wdac153.zip) contains a tool which can strip the header off a wave file (StripHdr.exe); such a tool shall be used to get raw compressed data in a clean way out of a compressed wave file. I wonder if it is allowed to distribute it separately; if not, it may not be a hard job to implement such a tool, even with a GUI. All it needs is 1) finding the "data" chunk, 2) extracting the data to a new file - simply removing 44 bytes would not be the correct way, though - compressed waves have at least an additional "fact" chunk and may contain even more chunks, which all do not belong to the compressed audio data.

[DSPguru]

LigH,
any decent ac3/mp3 decoder has a sync engine in order to handle corrupted streams. i implemented such a synchronizer in BeSweet, and most of the programs will usually skip the wav header very easily.

there are tons of Header removers out there. i recall that phillips' pub_enc package includes a format convertor that does -> wav2pcm.

[jokklas]

Hi, anyone have a clue as to how I can extract the AC3 from a DivX? VirtualDub/NanDub doesn't seem to be able to simply save it from the DivX. When I tried it sounded.. hmm.. weird as hell kinnda.

Thanks in advance / jokklas.