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philippas
11th December 2001, 04:07
Anyone knows any links for lossless audio codecs that can be used for AVI capture and then converted to mp3 ?

geniv
12th December 2001, 23:56
ummmm, I think it's PCM ;)

philippas
13th December 2001, 16:48
PCM is uncompressed format i'm looking an audio codec, like HuffYUV for video, which is lossless audio compression and can be used in Avi files.

sibe
13th December 2001, 16:50
A lossless audio codec that actually compresses audio is monkey's audio (http://www.monkeysaudio.com/index.html), but I don't know if it can be used for avis, I never tried it. My guess is: no.

But you should rather capture uncompressed audio because it's better and easier to go uncompressed -> mp3 than using another compression inbetween. And the audio filesize for uncompressed audio isn't that big (at least compared to your video filesize). If you don't have room for it on your HD you probably shouldn't try to capture at all.

Sibe

philippas
13th December 2001, 21:53
I've already tried monkey audio but it can't be used for avi files.
When i try to capture films or programs with length 2:30h or more pcm audio is about 3Gb. That's why i want to find a lossless audio codec which will reduce the filesize.

If you don't have room for it on your HD you probably shouldn't try to capture at all.

@ sibe You could think and say something more creative than that.

mpucoder
13th December 2001, 23:34
You should have ADPCM codecs already, which is a lossless compressor.

Psyche
14th December 2001, 00:29
@mpucoder:
Sorry to say this, but ADPCM is NOT a lossless codec. ADPCM (which stands for Adaptive Delta Pulse Code Modulation) is a relatively simple audio coding scheme which aims for up to 4x size gain. But it's not lossless because the error of the prediction stage can overload the number of bits allocated to delta, and thus not 1:1 conversion back.
@philippas:
Anyways, simple as it is, you should try it as the loss is not easily appreciated, and 4x gain turns your 3GB into 0.75 GB :) . Besides it's computationally quite efficient.

mpucoder
14th December 2001, 00:35
I guess that explains the exact binary compare after compressing and decompressing. You're thinking of alaw or ulaw, both of which are slightly lossy, but much better than mp3. Creative's ADPCM codec is an arithmetic 2:1 compressor.

Psyche
14th December 2001, 00:50
I'm not sure of understanding you correctly. What do you mean: guess that explains the exact binary compare after compressing and decompressing. Is it that you compared the compressed-decompressed file to the previous one and they were exact byte to byte? Of course this is possible, if the predictor stage never overloads the delta bits you get an 1:1. What I'm stating is that the files may (and in fact in most cases will) be different.

I don't know about Creative's ADPCM 2:1, it may be that this codec implements some mechanisms to keep it lossless (this is possible even with more advanced encoding techniques) but in general ADPCM is not lossless. Anyways these mechanisms will make it not be an exact 2:1 gain codec, if not how can you encode a white noise sample and get 2:1 compression?

Edit:

And no, I was not talking about alaw or mulaw, these are entirely different encoding mechanisms.

mpucoder
14th December 2001, 01:02
It seems I spoke a little too soon, and I appologize. The ADPCM codec from Creative that I used is no longer available, and may have been misnamed. It runs in 16-bit mode, and requires a SoundBlaster to be present. But, yes, it does get 2:1 losslessly.

sibe
14th December 2001, 22:52
@ sibe You could think and say something more creative than that.

I guess any lossless codec wouldn't give you a better result than compressing your audio to about 50%, so to stick to your example that would give you extra 1.5Gb, these would be (depending on your capture resolution, using huffyuv) 5-10 extra minutes of video. Imho thats not
worth it.
If disk size is that critical to you, you could capture your audio to mp3 directly. Or you capture and process your source in two halves, or you could capture in a lossy video format like mjpeg, mpeg2 or even divx directly. (I don't know your quality needs or your system specs because you were not specific about that.)

Creative enough?

Sibe

frigginjerk
14th December 2001, 23:57
http://www.nctsoft.com/products/NCTALFCD/index.html

Here you can get another audio codec, but I have no idea as to whether or not it lossless.

philippas
15th December 2001, 10:08
I think the solution for now will be to capture with mp3@320kbits and then recompress with lame vbr.
Thanks for all your replies.

robUx4
18th December 2001, 12:07
You could try FLAC, but I don't know if it's available as a codec (there's a winamp plug-in at least).