Surround Sound (5.1, etc.)

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
Post Reply
leon
Posts: 15
Joined: Fri Feb 16, 2007 6:58 pm

Surround Sound (5.1, etc.)

Post by leon » Fri Feb 16, 2007 8:39 pm

I see the MF 0.8.0b1 release notes and also the feature request summary both assert that "5.1 AAC audio" is a standard feature.

I'm struggling with how to verify that I'm getting 5.1 AAC audio into any output that MF 0.8.0b1 creates.

I have tried both of these:

AVI | AVC/H.264 Video / AC-3 Audio
AVI | MPEG-4 Video / AC-3 Audio

On the first format with QuickTime, and MPEG StreamClip, I just get a blank picture and no audio.

On the second format, I get a picture, but no audio.

Are there any QuickTime add-ons that will enable playing the above combinations?

Ultimately I want to find a combination to use Front Row and possibly AppleTV (yes, I see it's planned for MF futures); hoping to find a combination that works for Front Row, at least.

QT & MPEG StreamClip have this to say about the first format:
Video Tracks:
?, 720 × 304, 23.976 fps

Audio Tracks:
And for the second format:
Video Tracks:
DivX 5.0, 720 × 304, 23.976 fps

Audio Tracks:
? stereo, 48 kHz

So, is there something in the way of a plug-in or optional codecs that I can install for QuickTime and Front Row to allow them to play the MF generated video + 5.1 output formats per above?

Is there something different that I could be doing with MF to produce output with 5.1 audio that is compatible with QT & FR? Or is this a case of must wait for MF to include Apple TV support per the feature listed in the known requests page?

I *did* just discover that VLC is fine with both MF outputs with AC-3 audio and is showing 5 channels.

Is there some way to have QT and FR leverage the VLC stuff -- like a VLC "plugin" to QT? And would that help FR at all? (Yeah, I'm clueless on whether FR is completely separate or does it leverage QT extensions?)

jbrjake
Veteran User
Posts: 4805
Joined: Wed Dec 13, 2006 1:38 am

Re: Surround Sound (5.1, etc.)

Post by jbrjake » Fri Feb 16, 2007 8:51 pm

leon wrote:I see the MF 0.8.0b1 release notes and also the feature request summary both assert that "5.1 AAC audio" is a standard feature.

I'm struggling with how to verify that I'm getting 5.1 AAC audio into any output that MF 0.8.0b1 creates.
I think you might be confusing AC3 and AAC.

Right now MediaFork supports pass-thru of AC3, which is the dolby digital 5.1 surround track on most DVDs.

What's planned for the future (already available in the svn but NOT in beta 1) is 5.1 AAC.

QuickTime does not support AC3 pass-thru, which is why those aren't playing. You can download an AC3 component but even then it will only output downmixed stereo audio. You have to play those in VLC or Mplayer or whatever. The way to leverage VLC-style stuff in QuickTime is the insanely great open source QT component, Perian, but you still won't be outputting 5.1, I think. Should get the video playing with downmixed stereo audio, though.

AAC 5.1 will play in QuickTime, but you'll need a new piece of hardware (the Griffin FireWave) to send out all 6 channels of sound. Otherwise, it too will output downmixed stereo audio.

leon
Posts: 15
Joined: Fri Feb 16, 2007 6:58 pm

Post by leon » Fri Feb 16, 2007 9:00 pm

Excellent help, JbrJake!

I'll definitely be giving Perian a try!

So is there no known or forseable way to pass the MF encoded/passed-through 5.1 audio out my Mac's built-in TOSLink into my my receiver's TOSLink and still have it be interpreted as 5.1?

The Griffin HW product is only known/forseable way (pending MF 5.1 AAC encoding)?

jbrjake
Veteran User
Posts: 4805
Joined: Wed Dec 13, 2006 1:38 am

Post by jbrjake » Fri Feb 16, 2007 9:10 pm

leon wrote:So is there no known or forseable way to pass the MF encoded/passed-through 5.1 audio out my Mac's built-in TOSLink into my my receiver's TOSLink and still have it be interpreted as 5.1?

The Griffin HW product is only known/forseable way (pending MF 5.1 AAC encoding)?
Well, with passed-thru AC3, you can send it over TOSLink using VLC. That's how I play AC3 5.1 on my Mac.

With AAC 5.1....there is no way. Sorry. We're hoping the Apple TV will support it, as it as optical and HDMI.

To send AAC 5.1 out over optical, it has to be encoded as AC3, because that's what your receiver will understand.

But for QuickTime to do that, Apple would have to license the AC3 codec from Dolby. They apparently do not wish to pay this fee on every copy of QuickTime, which is, after all, freely downloadable. Of course, they should offer a for-pay component like the MPEG-2 one, but they don't. =( Anyway, we're hoping that Apple ponies up the licensing $$$ for the AppleTV so it can do this.

That Griffin device, incidentally, doesn't output over optical. You have to wire each speaker into it individually instead of using an amp :-(

leon
Posts: 15
Joined: Fri Feb 16, 2007 6:58 pm

Post by leon » Fri Feb 16, 2007 9:53 pm

JbrJake,

That answers all my original questions and more! Awesome!

So it sounds like it's 5.1 AAC that I will ultimately want and if that doesn't work with Apple TV then time to go beat up Apple. <smile>

Separately, I'll press Apple to add AC3 to Front Row -- far less of an "obligation" for them for FR (vs. QT), since it only runs on Mac HW that has the built-in iSight. Apple charges for OS upgrades, such as from Tiger to Leopard, so if not in Leopard, I'll make it a sticking point before I'll buy 10.6. Well, at least I can make lots of noise, anyway. <smile>

Does anyone know if Leopard's Front Row will already have AC3 support?

Also, with your pointers, I have the MF output, per start of this thread, playing back nicely.

At first, I couldn't get QT+Perian to work with the MF output files that I mentioned at the start of this thread. I get "Error opening movie / The movie could not be opened." I discovered that what I also need is something called the a52codec.

Perian+a52codec allowed full play back of both H.264 and MPEG-4 video + AC3 audio in BOTH QuickTime and Frontrow! Woot!

Maybe I'll get lucky and movies encoded this way with the AC3 passthru will just work on AppleTV. If not, then I'll just re-encode with 5.1 AAC as soon as someone knows definitively that AppleTV will work with MF generated files that use that audio encoding. Some "wait and see" required. <smile>

Thanks again for all the help!

jbrjake
Veteran User
Posts: 4805
Joined: Wed Dec 13, 2006 1:38 am

Post by jbrjake » Sat Feb 17, 2007 12:07 am

leon wrote:I discovered that what I also need is something called the a52codec.
Oops, my bad. For some reason I thought liba52 was included in Perian.

(Oh and for anyone else reading this who may have forgotten the top of the thread...this is playback of AC3, but not proper surround playback. Correct me if I'm wrong, leon, but last time I tried a52codec, it output stereo audio, which makes QT+Perian+a52codec sub-optimal for a home theater.)

leon
Posts: 15
Joined: Fri Feb 16, 2007 6:58 pm

Post by leon » Sat Feb 17, 2007 5:48 am

jbrjake wrote:Correct me if I'm wrong, leon, but last time I tried a52codec, it output stereo audio, which makes QT+Perian+a52codec sub-optimal for a home theater.)
You are quite right that the a52codec does not pass the AC3 out through to TOSLink. But at least I know my .avi file is encoded properly so that when Apple fixes this issue, I'm golden.

I'm mainly just trying to avoid the need to re-process all my movies at a future date. I just want a way to preserve the original surround sound content; I'm willing to wait for Apple to provide the necessary fix for that last step of actually going out to my receiver, but for now I can put the physical DVD's away.

While I wait for a fix, I'd sooner listen to my movies in plain stereo than add a 6-channel fire-wire audio device that would require a receiver with discrete channel inputs.

Maybe I'll get lucky and Apple TV will work with the AC3 pass-through files that MediaFork creates.

whimpers
Posts: 79
Joined: Mon Feb 19, 2007 1:03 pm

Post by whimpers » Mon Feb 19, 2007 1:13 pm

I'm affraid there's a very slim chance it will work with the AppleTV, since it seems to be very limited in the formats it understands, avi files don't seem to be one of them. It's even very doubtful that it will play mpeg4 files with aac 5.1 audio, since QuickTime only seems to support that in a .mov container for now.

maurj
Regular User
Posts: 148
Joined: Thu Jan 11, 2007 5:31 pm

Post by maurj » Mon Feb 19, 2007 7:30 pm

Hi whimpers,

QuickTime Player 7.1.3 will open mp4 files with 6-channel AAC files, but there's a bug on Intel which causes QuickTime Player to crash when you do. It works fine on PPC, or on Intel if you open QuickTime Player under Rosetta.

However, iTunes and FrontRow won't play these 6-channel mp4 files on either Intel or PPC, unfortunately. You have to open them in QuickTime Player (on PPC, or under Rosetta), and save as a .mov for them to work in iTunes and FrontRow.

We're hoping to get MediaFork creating .mov files as an additional file format sometime in the future, but for now I've put together a small Mac OS X droplet (which should be part of the beta2 release download) which will convert MediaFork's 6-channel mp4 files into 6-channel mov files, without the need to use QuickTime Player. They will then work in iTunes and FrontRow.

Nonsanity
Moderator
Posts: 46
Joined: Mon Feb 12, 2007 4:34 am

Post by Nonsanity » Mon Feb 19, 2007 8:10 pm

Has anyone tried the AAC 5.1 with a Griffin FireWave? I was just thinking about ordering one.

If can be tested with the new Fantastic 4 trailer (which has AAC 5.1) from Apple's trailer site:

http://www.apple.com/trailers/fox/fanta ... surfer/hd/

maurj
Regular User
Posts: 148
Joined: Thu Jan 11, 2007 5:31 pm

Post by maurj » Mon Feb 19, 2007 8:38 pm

Hi nonsanity,

I haven't got a Griffin FireWave, but I've tested MediaFork's upcoming 5.1 AAC support with an old eMagic 2:6, and a GigaPort AG, and it works on both of those. It should work fine with the FireWave.

BTW, be sure to make sure that your 5.1 amplifier has six discrete inputs - if it only has an optical input, you won't be able to plug the FireWave's 6 discrete outputs into it!

whimpers
Posts: 79
Joined: Mon Feb 19, 2007 1:03 pm

Post by whimpers » Tue Feb 20, 2007 8:51 am

maurj wrote:
QuickTime Player 7.1.3 will open mp4 files with 6-channel AAC files, but there's a bug on Intel which causes QuickTime Player to crash when you do. It works fine on PPC, or on Intel if you open QuickTime Player under Rosetta.
Yes, I managed to get AAC 5.1 audio in an mpeg4 file a while ago while using the Transcoding wizard in VLC (the only way I ever got this) and it played in QuickTime on a PPC, but I couldn't load it on my iPod (nor in iTunes like you mentioned) which makes me think that it will not play through an AppleTV either. And I'm affraid these .mov files won't either. I'm really curious to see if there will be a way to get real 5.1 audio playing through the AppleTV.

maurj
Regular User
Posts: 148
Joined: Thu Jan 11, 2007 5:31 pm

Post by maurj » Tue Feb 20, 2007 11:42 am

Hi whimpers,

I've converted several of the upcoming MediaFork beta2's mp4 files (with 5.1 AAC soundtracks) using the small MP4toMOV droplet we're including with beta2, and they all play fine in iTunes and FrontRow with full 6-channel output (through a 6-channel device). No-one knows (yet) if this will work on the AppleTV.

webjedi
Posts: 8
Joined: Mon Mar 05, 2007 4:08 am

so a question as to why?!

Post by webjedi » Tue Mar 06, 2007 6:08 am

So you get AAC 5.1/6... How is that really more beneficial than just having the AC3 track on a converted AVI.

I ripped X-Men 2 in an atttempt to get the 5.1 and, on the Mac Mini, using M-Audio's Transit USB, nada... nothing coming across as multi-channel. The AC3 one... not a problem.

So, I have a stack of DVD images now, and am I goign to wait and see about the Apple TV (and hope for AAC 6), or just go ahead and stick with the H.264 with AC3.

I'm gettign bored ddiling with sound formats at this point, and wished Apple would do something measurable for folks to care about sticking with Quicktime and MPEG-4. (Sorry for griping... I just feel like the audio argument is not worth it)

jbrjake
Veteran User
Posts: 4805
Joined: Wed Dec 13, 2006 1:38 am

Re: so a question as to why?!

Post by jbrjake » Tue Mar 06, 2007 4:19 pm

webjedi wrote:So you get AAC 5.1/6... How is that really more beneficial than just having the AC3 track on a converted AVI.
Well....because AAC is a hell of a lot smaller?

Or maybe because AC3 in an .AVI is a nasty hack?

AC3+MKV > AAC5.1+MP4 > AC3+AVI

Or maybe because the Apple TV is never going to play AC3+AVI but it might very well play AAC5.1+MP4?

whimpers
Posts: 79
Joined: Mon Feb 19, 2007 1:03 pm

Post by whimpers » Wed Mar 07, 2007 1:04 pm

Are you sure AAC 5.1 is that much smaller than ac3? When you try to keep the same bitrate (90 to 96 kbs per channel), the file size is about the same in my experience. Or do you feel that you can lower the bitrate with AAC because it's a superior compression scheme?
The main reason to use AAC 5.1 for me would be QuickTime compatibility, like you suggested.

jbrjake
Veteran User
Posts: 4805
Joined: Wed Dec 13, 2006 1:38 am

Post by jbrjake » Wed Mar 07, 2007 3:44 pm

whimpers wrote:When you try to keep the same bitrate (90 to 96 kbs per channel), the file size is about the same in my experience.
Well...yeah.
Or do you feel that you can lower the bitrate with AAC because it's a superior compression scheme?
Exactly. I've read that you can go down to 40 or 48 kbps for each channel. Were we using HE-AAC, even lower--16 or 24 kbps. But HE-AAC breaks QuickTime compatibility, so we're stuck with the less complicated version.

whimpers
Posts: 79
Joined: Mon Feb 19, 2007 1:03 pm

Post by whimpers » Wed Mar 07, 2007 4:41 pm

OK, thanks. Good to know.

deckeda
Regular User
Posts: 138
Joined: Thu Feb 22, 2007 8:38 am

FYI

Post by deckeda » Fri Mar 09, 2007 5:11 pm

Regarding the FireWave, I just asked Griffin about non-AC3 5.1 audio sources:

Regarding Dolby Digital, Dolby Pro Logic II support ... does that imply only from an AC3 soundtrack, or also from an AAC 5.1 soundtrack, such as what's inside some of the .mov movie trailers on apple.com?

and got back:
If a movie or video is already mixed in 5.1, then you will not have to engage anything on the Firewave's application. It will just work. If it is not mixed in 5.1, then you need to engage the Pro Logic II in the application to emulate 5.1 surround. Thanks for your interest.

hawkman
Veteran User
Posts: 609
Joined: Sat Feb 17, 2007 9:46 pm

Post by hawkman » Mon Mar 26, 2007 1:32 am

jbrjake wrote:Exactly. I've read that you can go down to 40 or 48 kbps for each channel. Were we using HE-AAC, even lower--16 or 24 kbps. But HE-AAC breaks QuickTime compatibility, so we're stuck with the less complicated version.
Is any information shared between channels for compression purposes, or what?

Like, 128kbps stereo generally sounds better than 64kbps mono... Is that all in my mind, or do multiple channels really compress better together? Or should I go with my guideline of ~64kbps per channel?

Ugh. Sorry, I know this isn't really handbrake-specific, but it's obvious you guys have to know at least something about this kind of thing so I thought I'd ask ;)

Post Reply