[X-Apps] Extracting Audio from DVD

[Said Nuseibeh]

Hi John.

Someone helped me with the very same issue awhile back. I will copy the 
messages below (Sorry for the wierd order).

Good luck,
-Said


On 1/2/2004 1:25 PM, John McGilvary (jmcgilvary at mac.com) wrote:

>Any specific apps folks like, and anything special I should know about 
>the process?


--------------------


Upon your lead about DVDExtractor I discovered two more sources of info:
http://mornmist.2y.net/~blibbler/tutorial/basic/
and
http://visionlab.harvard.edu/resources/DV/ripping.htm

Everything went fine except that I now have two 1.3 gb files of audio. 
The stereo channels extracted separately into two files of different 
size: 430mb and 184mb! Using mAC3dec I converted these two AC3 files to 
AIFF though, strangely, they both converted to 1.3 gb. I now have two 
stereo AIFF files with the same data on each channel. I've tried 
combining the selections from each file that I want within SonicWorx but 
the synching is quite difficult. I haven't yet found a way to delete one 
channel and replace just that channel with its counterpart from the other 
file. 

Is it normal that the .VOB extracted audio files are split stereo 
channels? Do you have any suggestions for obtaining a single stereo file?

Best Wishes,
-Said



On 6/22/2003 6:10 PM, Evan  wrote:

>>
>>
>>Oooh. Thanks for this info.
>>
>>Can you also advise how to extract tunes from a commercial DVD Video? I 
>>have a wonderful "1GiantLeap" DVD with wonderful mixes not on the CD. It 
>>would be nice to have some of them more portable.
>>
>
>Not hard - do a quick search for a DVD extractor - DVD extractor is one at
>http://www.afterdawn.com/software/alternative_platforms/mac_software/dvd_e
>xtractor.cfm
>Although if you live in the US, you're not technically supposed to 
>download it, due to some copyright stuff.  Hooray for Australia.  But 
>back to the topic - if somehow you acquire this program, you drop your 
>DVD in and locate the title --> chapter that you want to extract, tell 
>it to demux 'private' (audio) streams, and extract away.  Might take a 
>few tries until you find the track you want, but these things happen.
>
>When it extracts a pcm file, it'll just be a raw audio stream, you need 
>a program that will import them, and they'll be 48 kHz/16 bit/Stereo, 
>you'll have to downsample it to 44.1 kHz to go to CD.  I used SonicWorx 
>PowerBundle and did all this on a G4 Yikes, but there must be some free 
>software out there that lets you specify an aribitary sampling rate.  I 
>know that Bias Peak does (which has a downloadable LE version), but I 
>can't remember if it lets you open a raw audio stream.
>
>As for decoding an AC3 file, i'm not sure how that's done - all the 
>music DVD's I've ever ripped have had an Linear PCM stream, most do 
>because of the sound quality issue.  Here's a link to a decoder, though -
>
>http://sourceforge.net/projects/mac3dec
>
>I'll get out of your way now, I'll see you later
>
>Cheers,
>Evan.


-------------

Said Nuseibeh wrote:

>Thanks Evan.
>
>Everything went fine except that I now have two 1.3 gb files of audio. 
>The stereo channels extracted separately into two files of different 
>size: 430mb and 184mb! Using mAC3dec I converted these two AC3 files to 
>AIFF though, strangely, they both converted to 1.3 gb.
>
This is probably because AC3 files are compressed using an adaptive 
coding algorithm (very similar to variable bit rate MP3's) - often, 
there's much less audio information in the rear channels, so the files 
end up being smaller.  But when you decompress them to AIFF's, they end 
up the same size because AIFF's encoding is completely linear.

> I now have two 
>stereo AIFF files with the same data on each channel. I've tried 
>combining the selections from each file that I want within SonicWorx but 
>the synching is quite difficult. I haven't yet found a way to delete one 
>channel and replace just that channel with its counterpart from the other 
>file. 
>  
>
If you can be bothered sitting through a 12 meg download, get Pro Tools 
Free from http://www.digidesign.com
It lets you edit and shift around up to eight tracks of audio at a time, 
and it treats stereo files as two mono files, so if you import a stereo 
file, the program will split it into two mono files - then you pan one 
all the way left and all the way right.  The big advantage of this, of 
course, is that you can edit the two (or up to eight) channels 
completely independently of each other.  Then when you're done, you can 
'bounce' it all down to a normal stereo track, ready for CD burning.

You can download the manual for PT Free from the Digidesign website, 
it's a fairly full-on read.  If you need to know anything and can't be 
bothered filching through a 500 page PDF file for it, just drop me a 
line...I've been using the full 64 track version for about five years 
now, you get to know these things work....=]

>Is it normal that the .VOB extracted audio files are split stereo 
>channels? Do you have any suggestions for obtaining a single stereo file?
>  
>
The only time I've ever had to do this, I've used DVD's that had Linear 
PCM audio tracks, so it was ready to go after a quick
sample rate conversion.  But the above should help.