Comments on: The Correct Way to Enable AC3 Passthrough with Quicktime

By: Graham Booker

Graham Booker — Tue, 05 Oct 2010 01:21:54 +0000

Multi-Channel Output has nothing to do with passthrough. The method of turning it on and off are already described in this document.

By: Jack

Jack — Mon, 04 Oct 2010 21:01:08 +0000

Thanks Graham great work!,

Just to clarify: if “Multi-Channel Output” is selected in the Perian prefpane and passthrough is setup (following Graham’s instructions) then passthrough is on. But if anything else than “Multi-Channel Output” is selected in the Perian prefpane then passthrough is off. Allowing to easily switch if needed.
Is this correct?

By: Graham Booker

Graham Booker — Thu, 01 Jul 2010 12:04:06 +0000

kra,
You lose dynamic range. AC3 has greater dynamic range that what QT can handle.

By: kra

kra — Thu, 01 Jul 2010 04:53:32 +0000

Hi!
So I guess everybody heard the news about the new macmini being hdmi compliant.
Some steps are not necessary anymore. That’s actually what you should expect from an hdmi device, but well, it’s apple, so you want to double check.

Here’s my setup, it seems to be working ok, even though I technically have not tested with 6 speakers (only 3) , nor with DTS:
- AudioMidiSetup set to 96Khz/8ch/24bit. That’s the factory default actually.
- Make sure the AC3/DTS attemptPassthrough are set to false. (defaults write blabla 0 or delete blabla).
- Go to system preferences, perian and set audio output to “multi channel output”
- You still need to update the channel layout. Apple apparently didn’t fix the bug. If you don’t, when playing AC3, even though it will play (it didn’t before), the channels will be all messed up (center goes to right, etc…).

Good news is: it now also works for 6 channels discrete AAC.
Yay! Good bye AC3, hello AAC.
No need to change the channels layout with AAC.

On my receiver (sony str-dg something, don’t have the exact reference, sorry), I get the blessed “blue light” indicating 5.1, identified as Linear PCM, so apparently QT is decoding everything and sending the decoded pcm to the receiver (which is consistent with the fact that channels get messed when playing ac3/m4v with standard layout).

Overall, the situation improved:
- Still has the ugly bug with ac3,
- But aac 6 channels will work perfectly fine,
- aac 6 channels will give you a decent workaround the ac3 bugs (only for new files, though)
- Setup is less painful.

Let me know if I said anything stupid (it is likely, I’ve just been testing around for the last hour), and I’d be glad to get any feedback from anybody with the fancy new macmini

By: Graham Booker

Graham Booker — Wed, 03 Mar 2010 05:07:52 +0000

Again, this is not a support forum. No further comments will be accepted here. Replies with Make/Model of receiver are examined and the information is added to the post, but such posts will not appear. Those attempting to abuse this system will be denied access.

By: Dominik Pich

Dominik Pich — Fri, 07 Aug 2009 17:11:08 +0000

For many recceivers, but especially some sony ones:

set the receivers encoding!

for sony for example it was: DEC PCM
change it to: DEC AUTO

voila

By: Graham Booker

Graham Booker — Sun, 15 Mar 2009 02:16:50 +0000

This is not a support forum. Any comments not pertaining to the make/model of a receiver and whether it works will be deleted.

By: Graham Booker

Graham Booker — Sat, 23 Aug 2008 22:12:05 +0000

ionos,
On the audio settings, this is an issue with handbrake and it’s interaction with QuickTime. I suggested they use a version 2 atom in the m4v file 4 months ago (http://forum.handbrake.fr/viewtopic.php?f=4&t=4726&start=25#p33363) but was ignored. In addition, the default channel layout is inconsistent with Core Audio, which I reported to Apple 5 months ago (rdar 5799879) and was also ignored. If either of these two corrected they errors, this wouldn’t be an issue.

By: ionos

ionos — Sat, 23 Aug 2008 20:23:21 +0000

Oddest thing (All samples created with handbrake; please forgive me if I don’t get all the fancy abbreviations and terms right, I try my best):
AVI Mpeg4 with AC3 – works in QT and VLC (i.e., DD sound)
MKV H.264 with AC3 – works in QT and VLC
So, it should be considered established that the receiver works, the cables work, stuff is installed ok, etc.

M4V H.264 with AC3 – “Helicopter” in QT (i.e. the weirdo noise, input considered plain stereo by receiver), VLC seems to produce a valid stereo stream, but no surround sound.
M4V H.264 with AC3 and AAC – same thing.

Now, the funny part: In QT, open “Movie Properties”. Select Surround track, then “Audio Setting”. Swap “Right” and “Center”. Press play. Bang. Dolby Digital, say hello. Well, the receiver says the input was Dolby Digital, and I hear different things coming out of the various speakers.

Now, does that mean that the right channel is being played on centre, and vice versa? Doesn’t sound like it, most talking still comes through the centre channel.

By: Wim

Wim — Sun, 23 Mar 2008 21:43:58 +0000

I’m talking with Apple from the post-production site of the story… I’ve also reported the bug… I would like to have this feature on every mac with optical out… Let’s hope they listen…

Greetz,

Wim