Avi to wav extraction

[littlecramp]

Is there any program to extract only a portion of the sound from the avi w/o resorting to extract the entire wav file?

[teegee420]

Use Virtualdub and make sure "Direct Stream Copy" is selected for both audio and video. Use the "mark in" and "mark out" buttons to edit down to your desired selection, then go to "file" and select "save wav". If you want a true PCM wav select "Full Processing Mode" on the audio menu before saving, otherwise your wav will be the compressed audio.

[maxpower2078]

Goldwave, just open the file, set the in and out, crop it and save as a wav

[littlecramp]

When using "full processing mode", the output tend to have more noise than "direct stream copy". Is that true?

[mats.hogberg]

Direct stream doesn't process the audio at all, it just gives you the audio stream as found in the AVI, hence no quality loss. When doing full processing, the audio is decoded (and possibly even reencoded) which (at least when reencoding is involved) leads to a drop in quality, unless you use a lossless target codec.

/Mats

[littlecramp]

But if i need to convert the avi (in divx 5) format to Mpeg1 (VCD), I'll need to extract the uncompressed wav file according to the guide. Can I use direct stream for the wav file?

[Shudder]

If you extract the stream directly, you'll probably have about 1 meg per minute audio file, which even though it has a 'wav' extension, it's probably just an mp3 with a wav wrapper/header. If you're not in the mood to do the conversion in virtual dub, you can always do wav to wav in besweet and get a true wav file.

[mats.hogberg]

wav to wav in besweet

...or use CDEx to convert mp3 to wav or ac3fix + headac3he if it's ac3.

/Mats

[littlecramp]

Quote from -> shudder
"If you extract the stream directly, you'll probably have about 1 meg per minute audio file, which even though it has a 'wav' extension, it's probably just an mp3 with a wav wrapper/header. If you're not in the mood to do the conversion in virtual dub, you can always do wav to wav in besweet and get a true wav file."

Am I right to say there will be extras step to get the uncompressed wav? Will there be extras noise induced during the wav to wav conversion?

[teegee420]

I seriously doubt you will notice a significant amount of degradation when converting your avi audio to wav. Try it and find out. Either with the Virtualdub method that I suggested, CDex, or with Besweet, all of which will accomplish the same thing.

[littlecramp]

I'd try using virtualdub to extract it as uncompressed wav. The result is obvious tat there will be noise induced

[teegee420]

Does that mean you already tried it? If so, how much noise are we talking here? Is it dramatic?

[Shudder]

What do you mean by noise, and what exactly are you doing?

Going from avi to mp3 with wav header to pure wav to mp2 didn't really give me any noticeable quality issues. I'd probably have to really sit down to notice. At any rate, the difference after the conversion isn't enough to irritate me.

You either have a really bad source or you're doing something wrong.

[mats.hogberg]

avi to mp3 with wav header to pure wav to mp2 didn't really give me any noticeable quality issues

That's my experience too, and the only point in this operation wher the quality can drop is at the pure wav to mp2 stage, since mp2 isn't lossless. But using enough bit rate when encoding to mp2, this can be virtually unnoticable.

/Mats

[Shudder]

I think the original mp3 was about 128ABR, so I put the mp2 at about 192. How's mp2 compression compared to mp3 anyway? Hell, I should just suck it up and figure out ac3 eh?