What program can extract multiple audio channels from DVD?

[vivsavage]

I'm using Cinematize to extract data from DVDs, but it downmixes all audio into only 2 channels. Is there a solution that will perform extraction but keep all channels seperate (in other words, not downmix them)?

[StoryDonut]

Several apps will extract the AC3 audio file (mactheripper, bbdemux), and mac3dec will expand the AC3 into component AIFF files.

[pianoman719]

In Cinematize, I think you can set in/out points, then do more than one type of export to get everything you need. For example, you could export the video to a QuickTime editing format. Then export the audio to elementary streams, which should simply extract the .ac3 audio without downmixing. Then as StoryDonut said, use mAC3dec to convert the AC3 audio to multiple .aiff's. Putting it all together is the tricky part.

Without knowing exactly the nature of your project, I would suggest you try these tools to augment your workflow:

Yade X - Freeware Mac ripper that gives you a rough visual interface for choosing which parts of a DVD you want to rip. Will preserve AC3 audio tracks (will not downmix).

MPEG Streamclip - Freeware Mac MPEG2 editor and much, much more! Like Cinematize, will let you export or extract DVD footage, though not frame accurately. Will also let you extract AC3 audio or convert selected audio tracks to .aiff or .mp2. (Be sure and read the built-in guide.)

Apple QuickTime MPEG2 Playback Component for OS X - $20 download from the Apple Store. Needed to get the most out of MPEG Streamclip.

It would help if you told us more about your project. What are you trying to do with the extracted DVD footage? Edit it? In what program? Is it cuts-only editing, or do you need titles and transitions, and do you need to combine the DVD footage with other formats? Is the DVD a commercial film that uses film rate, or a self-made DVD with standard 29.97 material? After you finish editing, what will you do with the edited material? Burn it back to DVD?

-Pianoman

[Frobozz]

In Cinematize, I think you can set in/out points, then do more than one type of export to get everything you need. For example, you could export the video to a QuickTime editing format. Then export the audio to elementary streams, which should simply extract the .ac3 audio without downmixing.

I thought the same when I read vivsavage's post, but then I read this in the Cinematize user guide:
"The decoder will always downmix multi-channel audio streams (such as 5.1 audio with five full channels and one low frequency effects channel) to two channel stereo, since this is all most editing programs and computers can handle."

So the 5.1 audio gets downmixed to 2.0 with Cinematize. I know that MPEG Streamclip retains the 5.1 audio when it exports a muxed MPEG file. I haven't tried it with elementary streams. Toast 7 also retains the 5.1 audio when using its Media Browser to extract an MPEG from a video DVD. The reason I know this is from HD TS streams I've captured from my Comcast DVR and, with the help of MPEG Streamclip, burned them to a SD video DVD with Toast 7. The 5.1 audio was retained in this process. But I have never tried to extract only the audio as a 5.1 AC3 stream.

[maetel99]

If you extract the audio using the Elementary Stream setting in Cinematize you get a .ac3 file that has all the channels. I've tried this. Just like pianoman719 said, you can then use mAC3dec to decode all the channels.

Remember that multichannel audio playback really wasn't supported until QuickTime 7, so apps designed before that had no real way to output true multichannel audio except as a bunch of mono audio files. Also, I think you still cannot use more than two channel audio in iMovie, for example. For editing, you'll have to use QuickTime Pro or get Final Cut.