2 Audio Track question

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
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Bobcat37
Posts: 39
Joined: Tue Nov 25, 2008 5:51 am

2 Audio Track question

Post by Bobcat37 »

This has maybe been asked before, and if so, my apologies. I'm just curious, on the Universal and Apple TV presets, handbrake defaults to having 2 audio tracks. The first is an AAC Mixdown and the second is an AC3 Passthru. Since this is how the devs set it up, I also made my Custom DVD preset the same. My question is clarification on what the point of this is, and how it works. In other words -

I've always assumed the mixdown track was for iPod/iPhone compatibility? Is this the case? If not, why the 2 tracks?

Secondly, why is the Mixdown put as track 1 and the passthru as track 2? Does it have to be this way? I'm just annoyed lately when I boot up my movies in Plex and have to always go to the sound menu and switch to the passthru track, because it defaults to the mixdown (track 1). Can I put the passthru as the first track or would that mess something up, such as device compatibility?

And lastly, if I'm ripping an old stereo-only TV show like The Muppet Show, is there even a reason to have both, when they will both be stereo tracks? I'm thinking the answer is no...

Thanks for the help!
(Edit PS - just realized maybe this should be in the Mac thread? If a mod thinks so, feel free to move it)
TedJ
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Joined: Wed Feb 20, 2008 11:25 pm

Re: 2 Audio Track question

Post by TedJ »

Yes, the mixdown track is for use by the iPhone/iPod... the passthrough track is intended for the Apple TV and other compatible devices.

You could allocate the passthrough to track 1 or discard the mixdown track altogether, although there are instances where this has broken playback on devices that expect to see an AAC track as the first available audio track. The Apple TV is a prime offender.

The last question is purely a matter of personal taste, although generally speaking I don't bother with a passthrough for a stereo source.
Bobcat37
Posts: 39
Joined: Tue Nov 25, 2008 5:51 am

Re: 2 Audio Track question

Post by Bobcat37 »

Thanks Ted, that definitely helps. I think for future 2.0 and 1.0 sources I will discard the passthru as well... no reason to take up the extra space when the mixdown should be sufficient.

So I think I solved my second question through a few tests. I tried to rip a chapter of a 5.1 movie with only a Passthru track and my iPhone rejected it (Quicktime also wouldn't play it, but VLC would). Then I tried to rip the same chapter with the Passthru as track 1 and the Mixdown as track 2, and the iPhone and Quicktime STILL rejected it.

Does this sound correct to you?

I guess if I want iPhone compatibility, I'm stuck keeping the Mixdown as my first track. Inconvenient for Plex but what can you do...
TedJ
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Joined: Wed Feb 20, 2008 11:25 pm

Re: 2 Audio Track question

Post by TedJ »

I don't own an iPhone/iPod, but that behaviour sounds right to me.
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