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AC3 Passthrough

Posted: Mon Apr 30, 2007 9:56 pm
by ivan0327
I have been trying to encode a Ripped DVD (using MacTheRipper - Smokin' Aces) for Apple TV. But one of my main concerns is being able to keep the sound quality as possible.

Based on what I have read the best audio option would be to use AC3 passthrough. I know that quicktime will not be able to decode the audion unless I install a 3rd party codecs. But my main goal is to play my library of movies on my Apple TV with the best audio possible.

I was able to encode the music using the HandBrake GUI. But it seems that there is no option for AC3 passthrough. It seems that the track is "downmixed" to Dolby Pro Logic II. When the audio is encoded in this format I loose the subwoofer channel.

I tried using the CLI version of handbrake but it will not encode the movie if i use the option for AC3 passthrough - "-E ac3".

Below is the command line entry that I run:

./HandBrakeCLI -i /users/ivan/movies/SmokinAces/SMOKINACES/VIDEO_TS -o /users/ivan/movies/SmokinAces/sa_passthru_new_02.mp4 -v -c 4 -E ac3 -R 44.1 -6 dp12

the file will not open with quicktime. If i remove the AC3 passthrough option the the file encodes properly and no issue. Any ideas? Anyone able to encode with the AC3 passthrough?

Any and all help will be appreciated.......

Posted: Mon Apr 30, 2007 11:01 pm
by jbrjake
You cannot put AC3 in an MP4. Use AVI.

And don't use -6 unless you want aac 5.1, or a downmix. And you can't use dp12. It's dpl1. Or dpl2.

Posted: Mon Apr 30, 2007 11:08 pm
by ivan0327
Sorry the dp12 is a a typing error. I tried the -6 afterward to try different params.

The first attempt only had the -E ac3 option.

So the there is no way to truley play Dolby Digital 5.1 to an apple TV?

Posted: Mon Apr 30, 2007 11:23 pm
by jbrjake
ivan0327 wrote:So the there is no way to truley play Dolby Digital 5.1 to an apple TV?
The short answer is no, not easily, unless you hack the device. See the iPod/AppleTV forum section. There's a full discussion of it there.