AC3 + AAC in QT

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Joined: Mon Mar 08, 2010 5:43 am

AC3 + AAC in QT

Postby philoye » Tue Mar 09, 2010 3:28 am

I originally posted this in the Handbrake forums, but it might belong here.

I'm trying to create movies in a .m4v/.mov container with AC3 *and* AAC. I want to use AC3 as my primary sound output, but want to keep AAC for when I want to load it on my iPhone. I'm using a Mac Mini, not an Apple TV.

If my .m4v, .mp4, or .mov has AC3 only (no AAC), my receiver successfully decodes dolby digital. Meaning I've jumped through all the hoops necessary to do AC3 passthrough.

However, if the .m4v, .mp4, or .mov has BOTH AAC and AC3, when opening Quicktime Player prefers AAC even if AC3 is enabled/selected. If AC3 is selected/enabled in Quicktime properties, you save, then reopen, you'll see that the AAC track is re-selected. However, while it is open, you can disable AAC and enable AC3 and it outputs AC3.

Is this a Perian problem or a Quicktime problem? I doubt Handbrake is the culprit here...

This is with the latest Perian, Quicktime on 10.6.2 AND 10.5.8. I don't have an Apple TV, but I was hoping that AC3 and AAC could co-exist on the mac.

Any ideas?


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Re: AC3 + AAC in QT

Postby gbooker » Tue Mar 09, 2010 1:51 pm

Sounds like it's QT. Apple violated their own specifications in QT for how AC3 works in several other places, so it wouldn't surprise me to find out that they did here too.

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Re: AC3 + AAC in QT

Postby crzyhanko » Fri Apr 30, 2010 4:01 am

Philoye, two notes, if it helps:

1) I can't get movies with AAC+AC3 audio tracks to sync to my iPhone, so I'm not sure how much time you want to spend sorting this out before trying to sync your movies...

2) I found that if I set the language tag on the AAC track to something other than "English" (my system default), then by default iTunes and FrontRow will play the AC3 track (labeled "English") instead of the AAC one. Quicktime however still defaults to the AAC track. (note: I was using Subler to change the language designations on my audio tracks).

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