ac3 audio won't play in quicktime

[pixel zombie]

which is unusual as they will play on a dvd but once i extract them to my hard drive QT won't play the audio and i just recently updated the ac3 component, this is a problem as mpeg2works 4 won't properly demux/mux these files if QT can't play them properly...dual G5-10.4.8-quicktime 7.1.3

[Zekket]

My knowledge are limit but I think Quicktime 7 can't itself play AC3, Apple DVD Player can do it because have the components to do it, so you can hear AC3 audio on your DVD, I don't know if there is some kind of plugin in order to get AC3 working on QT (I use A.Pack, mpeg2works 4 and FFMPEGX to convert audio to AC3 all the time and never hear about Quicktime playing AC3). Some time ago I used Mpeg2works 4 with my DVDs but the program itself have a limitation (I start to think that it can be the same problem that I had, and the answer to your question), it can't demux a .VOB file with PCM audio (uncompressed audio like the one of iDVD when your DVD soundtrack was made from an AIFF audio), mpeg2works only can handle the ones with .AC3 audio, if you use the "demux .vob with ac3 audio" option on a .VOB with .PCM audio then you get a lot of 0kb ac3 files or a file that do not have sound at all. You need to check if your DVD's audio is really AC3, if not, then you need another tool (ffmpeg is great and better than mpeg2works for that task, believe me) and then... convert the PCM to AIFF (I use AIFF from PCM) in order to hear the sound file of your DVD on QuickTime, every time I backup a movie to my Mac I change the AC3 to MPEG audio before to mux my MPEG2 video to get the sound playing on QT (it's the same audio type of a VCD, and for at least 4 years I used QT to play VCDs on Mac without problems, now I use VLC).
Quicktime can play PCM muxed on a MPEG2 (if the PCM it's alone can not play it) but I don't think you want to have 1GB of audio on your movie when the compress one could have 200MB.
I hope it will be a litte bit useful ^^U.

[havema-1]

MPEG Streamclip can play and convert video with AC3. PCM and M1A audio (for MPEG2 you need the MPEG2 Playback component from Apple).

[dnix71]

ffmepgX supports Dolby ac3, so recoding the audio to stereo should make it easier to play off disc.

All those extra channels have to be combined on the fly if you only have two speakers, so if you don't have a theater setup from your computer, stereo is all you need.

[Ai Haibara]

pixel zombie: Which AC3 component are you using? If you're using this one: http://www.macupdate.com/info.php/id/14633 , I'm not sure if it works with QT 7 (despite the comments on the MacUpdate page I've linked to. I'm still using QT6.)

You might try the A52Codec: http://trac.cod3r.com/a52codec/

[terryj]

You might try the A52Codec: http://trac.cod3r.com/a52codec/

this and this one one are the two I have in my QT library/plugins
and they work ok:

AC3 Codec for Mac OS X - 0.4b1