I tried to follow the simple steps above to enable surround sound from my macbook but after many hours, no luck. I downloaded Perian and the preference editor and followed all of the steps but in Quicktime, Front Row and iTunes I still only get PLII. Any help? Here's the background:

- OS10.5
- Connected via optical/Toslink to AVR (shows as optical on display so that is working)
- downloaded and installed Perian and set up for multi channel out
- Audio MIDI setup changed (actually, I tried 2 different settings here. Changed to 48khz but then tried leaving as 2-channel out and as multi-channel out. In both cases it had no effect on outputting 5.1)
- Edited the Dolby Digital preference file as described. Since I used the recommended preference editor I had to use 'integer' as the class instead of 'number' but I think that should not make a difference.

Any ideas? Very happy with everything else about this setup other than the lack of surround sound. Thanks.

I wasn't aware that Perian supported DD or DTS overt toslink/spdif.

Was able to output Dolby Digital thru combo speaker output on Macbook using a regular optical cable with adapter on one end and the other end going into the receiver

Played movie with VLC, Dolby Digital recognized right away, make sure you have the settings on your receiver correct, if its set to Hall or something, then it wont play DD

It may not do DD or DTS, I was trying to play back content from iTunes that I thought was coded with 5.1 surround. The AVR is set to play back the signal direct or 'pure' with no processing. When I do that I only get 2 channels. Maybe I am wrong about the content? I tried playing battlestar gallactica and a few TV shows that I thought were 5.1, is there a way to check inside iTunes about how they are encoded?

BSG is listed at the iTunes Store as DD 5.1 Surround. No idea if that's actually true or not....

iTS content may only be 5.1 on the AppleTV.

open the file with Media Infor Mac and see if it is multichannel or if it is just stereo

tex94, I didn't think Macs could play back iTunes content with true DD 5.1--Macs can play back all sorts of content with DD 5.1 and DTS in Apple dvd player, Front Row, VLC, etc just not "iTunes."

I wasn't aware that Perian supported DD or DTS overt toslink/spdif.

It does support AC-3/DD 5.1, Perian has the A52Codec, it's just that Apple's support for making AC-3 passthrough available through Quicktime is very poor. A Perian developer, who posts at the Perian forum as gbooker, has been writing about this Apple and AC-3 issue for about a year now, ever since the Quicktime 7.4.1 update first broke AC-3 passthrough for some of us for certain files within Front Row last summer.

tex94, if you're following the "geekwithfamily" link instructions, don't--that hack (I don't know if it has been corrected since) has been discredited by the Perian developers and you're messing up the functionality of your system for other things. Graham Booker has provided a better hack to restore AC-3 which works with certain AVRs, but not others. And he's very explicitly pointed out to Apple what the bugs are and what needs to be fixed.

http://www.cod3r.com/2008/02/the-correct-way-to-enable-ac3-passthrough-with-quicktime/

There is A LOT of discussion here about AC-3:

http://forums.cocoaforge.com/viewforum.php?f=25

The problem is, without Apple's cooperation, we won't get something that's seamless and just works for everyone. That's why more and more folks are trying, and staying with, Plex, which handles the AC-3/multichannel audio side of things better.

tex94, I didn't think Macs could play back iTunes content with true DD 5.1--Macs can play back all sorts of content with DD 5.1 and DTS in Apple dvd player, Front Row, VLC, etc just not "iTunes."

Does that mean iTunes purchased content or are you referring to the software used to play back the content. I thought there might be issues with the iTunes software which is why I also tried to playback via Front Row and Quicktime as well. But if it is the content then I guess I could try and rip DVD with handbrake to see if that works.

Or rather, I would if I didn't read the rest of your post...


tex94, if you're following the "geekwithfamily" link instructions, don't--that hack (I don't know if it has been corrected since) has been discredited by the Perian developers and you're messing up the functionality of your system for other things. Graham Booker has provided a better hack to restore AC-3 which works with certain AVRs, but not others. And he's very explicitly pointed out to Apple what the bugs are and what needs to be fixed.

http://www.cod3r.com/2008/02/the-correct-way-to-enable-ac3-passthrough-with-quicktime/

There is A LOT of discussion here about AC-3:

http://forums.cocoaforge.com/viewforum.php?f=25

The problem is, without Apple's cooperation, we won't get something that's seamless and just works for everyone. That's why more and more folks are trying, and staying with, Plex, which handles the AC-3/multichannel audio side of things better.

I completely agree. Other than trying to get people to buy AppleTVs I dont know why they can't just support this in the software. I'd pay extra for a premium version of QT, FrontRow oe iTunes for that.

iTS content may only be 5.1 on the AppleTV.Frak! Quicktime tells me the audio of the BSG ep I recently purchased is (L R) Stereo 48000 kHz. Been thinking about getting an aTV, but that's currently the only way to get 5.1 from purchased TV shows.....? :eek:

Frak! Quicktime tells me the audio of the BSG ep I recently purchased is (L R) Stereo 48000 kHz. Been thinking about getting an aTV, but that's currently the only way to get 5.1 from purchased TV shows.....? :eek:

Hmm, looking into more of my iTunes content and it appears that it has all downloaded as AAC (protected) - Stereo L/R at 48kHz. This despite the fact that it says for many of these that it is available with 5.1 sound. So now I'm wondering whether this is another intentional cripple meant to get me to buy an aTV. Perhaps they are only enabling the 5.1 audio portion if you send to aTV (just like they don't allow HD movie rentals to a computer). What a pain. I really would prefer to have a single device to get to the web, etc. Now if they gave me safari and boxee easily I might change my mind. In the meantime, I'll pass on buying both the aTV and iTunes content

My understanding, which could be wrong, was that only the HD versions of the shows on iTunes had 5.1 sound. Are the ones you purchased the HD versions?

Also, the way Apple is encoding the files, the default audio track is AAC stereo and a second audio track is the AC3. If you play in Quicktime, you should be able to select the second audio track. In iTunes, only the AAC will be played. I can't remember if there's a way to select the second track in FrontRow.

My understanding, which could be wrong, was that only the HD versions of the shows on iTunes had 5.1 sound. Are the ones you purchased the HD versions?

Also, the way Apple is encoding the files, the default audio track is AAC stereo and a second audio track is the AC3. If you play in Quicktime, you should be able to select the second audio track. In iTunes, only the AAC will be played. I can't remember if there's a way to select the second track in FrontRow.

I think you are right. The downloads I used are HD versions and I found at least 1 (The Tudors) that I can find the surround sound file on in QT. Unfortunately, I still could not get 5.1 sound from my receiver. I get no sound at all when I select that track. I'm now thinking that perhaps there is some connectivity issue with my AVR and the Macbook is not recognizing that it can send digital there or my AVR is just not recognizing how it is encoded.

I have a similar problem with AC3 audio playback (It won't play). My system is not connected to a audio receiver or a sound card that has surround sound but this might help spark a clue for the problem you are having.

My system is a older PowerPC G4 450MHz (upgraded to 1 GHz) running Tiger 10.4.11. Since upgrading to QuickTime 7.6, none of my ".mov" or ".ac3" files will play in iTunes 8.0.2, QuickTime 7.6 or Front Row 1.3.1 (I get nothing but noise). After taking a look at the movie properties the audio file is labeled as AC3 5.1 channels, which these files played on previous versions of QuickTime. I have the latest version of Perian 1.1.3 installed along with the A52Codec.

I hooked up an extra hard drive that had Tiger 10.4.11 and the previous version of QuickTime 7.5.5 installed, restarted to this drive and guess what, the ".mov" and ".ac3" files played with no problem. Looks like QuickTime 7.6 will not play AC3 files at all.

What I then did, while still in QuickTime 7.5.5, I made a copy of the movie file that had AC3 audio, extracted the Audio file from the movie, exported the audio only as a QuickTime Movie, clicked on options, format was AAC with 5.1 channels. After converting the AC3 to AAC, I opened the movie, did an add to movie which gave me a second audio track labeled ACC, I deleted the AC3 audio file, enabled the ACC audio file saved the new movie as "Test".

I restarted to the drive that is my current system with and QuickTime 7.6, iTunes 8.0.2 and Front Row 1.3.1 plays the movie fine with no audio problems.

Now looks like I have to convert all of the audio files to AAC.

If someone else has another answer or way of converting let me know.

Thanks.
Bill

I have a similar problem with AC3 audio playback (It won't play). My system is not connected to a audio receiver or a sound card that has surround sound but this might help spark a clue for the problem you are having.

My system is a older PowerPC G4 450MHz (upgraded to 1 GHz) running Tiger 10.4.11. Since upgrading to QuickTime 7.6, none of my ".mov" or ".ac3" files will play in iTunes 8.0.2, QuickTime 7.6 or Front Row 1.3.1 (I get nothing but noise). After taking a look at the movie properties the audio file is labeled as AC3 5.1 channels, which these files played on previous versions of QuickTime. I have the latest version of Perian 1.1.3 installed along with the A52Codec.

I hooked up an extra hard drive that had Tiger 10.4.11 and the previous version of QuickTime 7.5.5 installed, restarted to this drive and guess what, the ".mov" and ".ac3" files played with no problem. Looks like QuickTime 7.6 will not play AC3 files at all.

What I then did, while still in QuickTime 7.5.5, I made a copy of the movie file that had AC3 audio, extracted the Audio file from the movie, exported the audio only as a QuickTime Movie, clicked on options, format was AAC with 5.1 channels. After converting the AC3 to AAC, I opened the movie, did an add to movie which gave me a second audio track labeled ACC, I deleted the AC3 audio file, enabled the ACC audio file saved the new movie as "Test".

I restarted to the drive that is my current system with and QuickTime 7.6, iTunes 8.0.2 and Front Row 1.3.1 plays the movie fine with no audio problems.

Now looks like I have to convert all of the audio files to AAC.

If someone else has another answer or way of converting let me know.

Thanks.
Bill

Interesting...and frustrating. Maybe Apple will just fix this in the next release of Quicktime. Honestly, I don't understand why they don't just enable iTunes and Quicktime to both just offer 5.1 sound, at least on the HD programs. In the meantime, sounds like I'll have to live with it as is which means buying less iTunes programming.

I think you are right. The downloads I used are HD versions and I found at least 1 (The Tudors) that I can find the surround sound file on in QT. Unfortunately, I still could not get 5.1 sound from my receiver. I get no sound at all when I select that track. I'm now thinking that perhaps there is some connectivity issue with my AVR and the Macbook is not recognizing that it can send digital there or my AVR is just not recognizing how it is encoded.

To put it simply, Quicktime that is used by iTunes, Front Row, etc is unable to play 5.1 surround - even those embedded in the HD TV shows that Apple sells. However, the Quicktime version of AppleTV is able to play them without any problems. In iTunes, you can pick which sound track you want to play. When you pick 2 channel, it plays. When you pick 5.1 channel, there is nothing! I filed this as a bug in Apple Developer site and they linked it to another bug for which I don't have any visibility. No status updates either! Very frustrated. BTW, the Windows version of iTunes/Quicktime has the same problem.

Since upgrading to QuickTime 7.6, none of my ".mov" or ".ac3" files will play in iTunes 8.0.2, QuickTime 7.6 or Front Row 1.3.1 (I get nothing but noise)

I have a similar problem with AC3 audio playback (It won't play)

Bill, you do have a problem, but it isn't the same problem the rest of us have, since we're talking about passing AC-3 out to a receiver untouched. A Mac can't play back AC-3 as is because it can't decode AC-3 nor can your Mac pass it through to an AVR, without additional hardware and drivers, like with an M-Audio USB or firewire interface, because a G4 450 MHz doesn't have built-in digital audio out. So, if you were hearing something before when playing back those files, there was a "mixdown" to 2 channel going on either in AudioMIDI or when it was handed off to CoreAudio, essentially your AC-3 only track was being downconverted to PCM stereo so you could hear it because that's all your Mac was capable of. If you're not hearing anything now, or just hearing noise, that mixdown is what is being interfered with--and frankly, that's not something I have any experience with because most of us try NOT to get that internal mixdown to 2 channel stereo.

We tweak and install and uninstall and hack to KEEP AC-3 passthrough--that's what we're usually talking about when we say Quicktime and AC-3 is broken. Fortunately, VLC can still play most .avi, .mov and .mkv files with "AC3 only audio" fine through the encoded digital out--as long as your Mac has digital out, that is.

I hooked up an extra hard drive that had Tiger 10.4.11 and the previous version of QuickTime 7.5.5 installed, restarted to this drive and guess what, the ".mov" and ".ac3" files played with no problem

For some of us, this AC3 passthrough problem started even earlier with the Quicktime 7.4.5 upgrade, everything worked fine in 7.4.1, afterward, no.

I have the latest version of Perian 1.1.3 installed along with the A52Codec.

The A52Codec is included in Perian, did you install it separately as well? Are you still trying to set attemptPassthrough 1 in com.cod3r.a52codec and the com.cod3r.a52coder plist (reset passthrough) or are you changing settings with 1.1.3 within System preferences > Perian > Audio Output? You might try toggling between the options here...make sure you try stereo or DPL and NOT set it to "multi-channel out," since, well, you don't have any capability for multichannel out. See if that restores your AC-3 to 2 channel mixdown.

When you look in AudioMIDI, what is it set to?

Also, have you tried playing the same files back with VLC? (Or Plex or Boxee.) What happens, does VLC mix AC-3 down to stereo so you can hear audio rather than noise?

Now looks like I have to convert all of the audio files to AAC.

Well, probably better to keep the original AC-3, and add the new ACC.

That's why Handbrake added a preset for aTV with two audio tracks, the first a default AAC, the second an AC-3. I'm not sure there's a better way around opening up each file individually in QuickTime Player, saving the audio as AAC, opening the saved AAC track, adding it to the original movie, and then saving.

Honestly, I don't understand why they don't just enable iTunes and Quicktime to both just offer 5.1 sound, at least on the HD programs

Quicktime that is used by iTunes, Front Row, etc is unable to play 5.1 surround - even those embedded in the HD TV shows that Apple sells

Right, our best hope on the AC-3 passthrough front is for Apple to bring HD rentals to the Mac desktop.

Right, our best hope on the AC-3 passthrough front is for Apple to bring HD rentals to the Mac desktop.

Yes. And I think that has to come at some point in the next 12 months. There is too much growth in the video download/streaming space for Apple to just pass it up. And I don't think a closed system like aTV is going to work for long because there are too many other choices people will also want (I know there is Boxee but I can't imagine most people figuring out how to load that, no matter how easy they make it.) With the dropping price of computers and the growth of HDMI most people would be happy just hooking up their laptop to the TV with 1 connection and playing whatever they want while having the option to take it with them by unplugging it. Apple/iTunes could own that space but they need to enable the video and sound quality to make it real. If it isn't drop dead easy for consumers to just buy a program from iTunes and play it back and get great PQ/AQ customers will find another option.