HOW DO I EXTRACT AUDIO FROM A DVD?

[marwen]

I have several DVD's that I want to export or else import - (I really don't know which way is better) selected areas within the overall audio.

Any suggestions will be most welcome.

marwen

[kozikowski]

You might follow the instructions for recording internet audio or audio on the computer. They all do the same thing and fold the record and playback into each other so you can capture forbidden sound.

http://wiki.audacityteam.org/wiki/Recor ... e_computer

Remember to turn all that back off again when you're done. This process messes up straight computer recording.

Koz

[Gale Andrews]

If you want to get more sophisticated and avoid the audio losses you will get by recording the audio as it plays, you can use Audacity Beta 1.3.12, install FFmpeg then you can drag the VOB files off the DVD into Audacity, without losses. You won't get the whole DVD audio in one piece that way, but you can join the files together in Audacity.

If the DVD is encrypted (protected) as most commercial DVDs will be, you can try DVD Decrypter. This will let you copy the complete DVD with video to your hard drive; or to extract (demux) the audio on its own. If you prefer you can select specific chapters to extract the audio/video from. There is a tutorial here. If you demux, the audio may be in AC3 or AAC format. In that case you will need Audacity Beta with FFmpeg to import it into Audacity if you want to edit it.

As always, you make your own decision about the legality of what you want to do.

DVD demux/decrypt tools for other platforms:
vobcopy for Linux

OSEx for Mac OS X

MactheRipper (OS X)





Gale

[marwen]

Thanks Gale:

I think this is the way I want to go. All of my DVD's have been decrytped - with DVDShrink.

I have tried to extract the audio files with my current version of AUDACITY but when I hit any of the "larger" sections of the VOP files - it wants to take "forever".

I presently have version 6 so I 'll have to download the newer 12.

I'll keep you posted with the results

marwen

[kozikowski]

<<<when I hit any of the "larger" sections of the VOP files - it wants to take "forever".>>>

Movie DVDs are highly compressed. When you try to unfold a movie into its parts, suddenly the movie reverts to its real size. Say a 90 minute movie, 24 frames per second (really 23.976fps) comes out to 129.6GB. You got room for that or time to wait?

Oh, and there are at least two sound tracks, the AC3 surround and the standard Stereo PCM -- frequently missing. Can you decode Dolby AC3 and then manage the resulting six audio tracks? Even if you fudge it, you still need at least three. Dialog is almost exclusively on the center channel.

Koz

[Gale Andrews]

Movie DVDs are highly compressed. When you try to unfold a movie into its parts, suddenly the movie reverts to its real size. Say a 90 minute movie, 24 frames per second (really 23.976fps) comes out to 129.6GB.

Audacity is only decompressing the audio stream, and any individual VOB (including video) can't be more than 1 GB. The file size of what Audacity extracts depends on the Quality Preferences you choose. By default (44100 Hz, and with FFmpeg always importing at 16-bit resolution), that means 10 MB per minute for stereo audio. So if the playing time of the VOB is 30 minutes, that's 300 MB of disk space.

If there are multiple audio streams, I think a dialogue should appear asking which you want to import, though it's a long time since I tried that.


Gale

[kozikowski]

<<<ny individual VOB (including video) can't be more than 1 GB.>>>

That's the encoded Video Object, with usually four of them making up the actual movie (given no funny business protection) with the rest of the 8GB taken up with director comments and coming attractions. However, you still can't "just" decode the audio streams. You have to render the video portion first and then demux it. That's why it suddenly takes a million years to do if you try to demux an entire quarter of the movie. Even if it does it MPEG2 block by block, the work and the video streams have to go somewhere, and it can take a long time.

[Gale Andrews]

That's the encoded Video Object, with usually four of them making up the actual movie (given no funny business protection) with the rest of the 8GB taken up with director comments and coming attractions. However, you still can't "just" decode the audio streams. You have to render the video portion first and then demux it. That's why it suddenly takes a million years to do if you try to demux an entire quarter of the movie. Even if it does it MPEG2 block by block, the work and the video streams have to go somewhere, and it can take a long time.

Does FFmpeg render the video when it extracts the audio in Audacity?

I haven't got an unencrypted DVD to try, but using a 1 GB VOB (containing audio and video) decrypted from a DVD by DVD Decrypter, the 30 minutes of audio imports into Audacity in about 45 seconds, the Audacity temp file has the expected 300 MB of stereo audio (FFmpeg decompresses at 16-bit, I keep forgetting that), and I have had about 100 MB added to my swap file. No other space has been used on the C drive in the extraction process.


Gale