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Old Mar 21, 2007, 02:33 PM   #1
smdewart
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Rip DVDs w/ Dolby Digital 5.1 sound & Play over Apple TV?

Wondering if there's any DVD ripping program that is able to extract 5.1 audio (read: discrete channels, not matrixed surround sound) that, in turn, can be streamed to an Apple TV box?

From what I've read and tried, DVD-ripping programs can only encode MP4 video with two-channel audio, but, by all means, please prove me wrong!
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Old Mar 21, 2007, 03:22 PM   #2
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Handbrake's next release will support 5.1 AAC. I have been toying with it, and it is quite good.

As for if it will work with the Apple TV? Nobody knows yet.
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Old Mar 21, 2007, 03:36 PM   #3
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Apple TV does not support multi-channel surround sound. Even if HandBrake adds 5.1-channel AAC (not AC-3), there aren't any receivers/processors that can decode it. You will be stuck to glorious stereo.
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Old Mar 21, 2007, 03:38 PM   #4
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Quote:
Originally Posted by nutmac View Post
Apple TV does not support multi-channel surround sound. Even if HandBrake adds 5.1-channel AAC (not AC-3), there aren't any receivers/processors that can decode it. You will be stuck to glorious stereo.
While there isn't any literature regarding Dolby Digital Live and Apple TV... you can generate AC-3 on the fly from 5.1 AAC. Hell, the 360 does this for games, and for HD-DVD discs that use Dolby's HD audio codecs.
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Old Mar 21, 2007, 03:39 PM   #5
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Quote:
Originally Posted by Krevnik View Post
Handbrake's next release will support 5.1 AAC. I have been toying with it, and it is quite good.

As for if it will work with the Apple TV? Nobody knows yet.
Where can you find that version of HB?
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Old Mar 21, 2007, 03:51 PM   #6
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Originally Posted by princealfie View Post
Where can you find that version of HB?
It is in their SVN tree... it hasn't been made ready for public consumption just yet.
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Old Mar 22, 2007, 12:48 PM   #7
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are you sure?

Quote:
Originally Posted by nutmac View Post
Apple TV does not support multi-channel surround sound. Even if HandBrake adds 5.1-channel AAC (not AC-3), there aren't any receivers/processors that can decode it. You will be stuck to glorious stereo.
Are we sure that Apple TV does not support AC-3 output? We know iTunes purchased TV shows and movies do not (they only have ProLogic surround embedded in 2 channel audio, as I understand it). But somebody is going to have to try to run some ripped multichannel files to see what happens with Apple TV.
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Old Mar 22, 2007, 06:23 PM   #8
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Quote:
Originally Posted by Krevnik View Post
While there isn't any literature regarding Dolby Digital Live and Apple TV... you can generate AC-3 on the fly from 5.1 AAC. Hell, the 360 does this for games, and for HD-DVD discs that use Dolby's HD audio codecs.
While it is a possibility, I wouldn't bet on it. Perhaps Apple will charge $2 for Dolby AC-3 encoder, but then again, iPod can theoretically playback WMA, Ogg Vorbis, etc. as well. But it doesn't.

As for Xbox 360, no, it does not generate AC-3 from AAC (since it does not support AAC). HD DVD does not use AAC either (it has Dolby E-AC-3 or Dolby Digital Plus, which is designed to convert easily into AC-3). For games, Xbox 360 generates AC-3 from Microsoft's own format via dedicated audio processor.

While your assumption may be possible, I wouldn't bet on Apple TV's 1 GHz Intel Pentium M to do that, especially while playing back 720p video. It would make more sense for Apple to license AC-3 for QuickTime and Apple TV instead of licensing Dolby Digital Live. Why tax Apple TV with converting 5.1 AAC (which it does not presently support) to AC-3 unnecessarily?

Quote:
Originally Posted by ces1965 View Post
Are we sure that Apple TV does not support AC-3 output? We know iTunes purchased TV shows and movies do not (they only have ProLogic surround embedded in 2 channel audio, as I understand it). But somebody is going to have to try to run some ripped multichannel files to see what happens with Apple TV.
Yes, Apple TV does not support AC-3. QuickTime doesn't support (without third party add-on), neither does Apple TV. In order for Apple TV to playback AC-3, Apple needs to pay license to Dolby and update QuickTime and re-encode video on iTunes Store with AC-3 track.
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Old Mar 22, 2007, 07:15 PM   #9
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Quote:
Originally Posted by nutmac View Post
As for Xbox 360, no, it does not generate AC-3 from AAC (since it does not support AAC). HD DVD does not use AAC either (it has Dolby E-AC-3 or Dolby Digital Plus, which is designed to convert easily into AC-3). For games, Xbox 360 generates AC-3 from Microsoft's own format via dedicated audio processor.
Although the Xbox doesn't support AAC, it will convert WMAPro 5.1 into AC3. Also, the 360 decoded the Dolby Digital Plus into PCM, mixes in menu sounds and what not, then encodes it into regular Dolby Digital, which is what Krevnik was talking about.
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Old Mar 22, 2007, 10:05 PM   #10
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this is unfortunate

I bought the appletv thinking, i could encode some of my own movies, and i am sure a flurry of movies will start to appear on various torrents encoded h.264/itunes compatible format....but it now seems that 5.1 surround sound will not be possible at this time.

I personally have not tried encoding a movie yet, but after reading this forum and the handbrake forum, it seems that at least one person has tried 5.1 encoding, but the streamed signal, is stereo only

here is a link to that: http://handbrake.m0k.org/forum/viewtopic.php?t=692

i hope i am wrong, or something will change really soon. I would think in todays world, if you have widescreen/hi def tv, you probably have or will soon have 5.1. Even if you took the time to encode some of your movies, in itunes hd format, you are still better off watching dvd or hi def cable for movies. who wants to watch a movie in stereo, when you have all those speakers surrounding you. shame on you apple
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Old Mar 22, 2007, 10:19 PM   #11
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Quote:
Originally Posted by traderx1 View Post
I bought the appletv thinking, i could encode some of my own movies, and i am sure a flurry of movies will start to appear on various torrents encoded h.264/itunes compatible format....but it now seems that 5.1 surround sound will not be possible at this time.

I personally have not tried encoding a movie yet, but after reading this forum and the handbrake forum, it seems that at least one person has tried 5.1 encoding, but the streamed signal, is stereo only

here is a link to that: http://handbrake.m0k.org/forum/viewtopic.php?t=692

i hope i am wrong, or something will change really soon. I would think in todays world, if you have widescreen/hi def tv, you probably have or will soon have 5.1. Even if you took the time to encode some of your movies, in itunes hd format, you are still better off watching dvd or hi def cable for movies. who wants to watch a movie in stereo, when you have all those speakers surrounding you. shame on you apple

I'm a Dolby licensee and I'm pretty well versed in AC-3 encoding, etc.

What I have gathered thus far (and yes, I picked up an AppleTV today) is that AppleTV does in principle have the hardware but not necessarily the software (yet) to support AC-3 transcoding.

The Intel HD Audio chipsets do seem to be specifically geared toward implementation of Dolby Digital Live which is the key technology licensed out by Dolby for exactly this kind of application... transcoding multichannel bitstreams into AC-3. In this case, specifically transscoding AAC into AC-3.

If the Intel HD Audio chipset in the AppleTV is in fact capable of supporting Dolby Digital live, then really only a firmware and software update is required to enable at least multichannel AAC playback to push through the chipset and transcode it on the fly.

The AAC bitstream could probably be at 320kbps, which is the bitrate of AC-3 in theatrical prints. 448kbps is the bitrate of AC-3 on DVD but AAC is a more efficient perceptual coding schema and outperforms AAC at every bitrate. This wouldn't be that taxing on G and certainly not hard at all for N wireless streaming.

As for licensing from Dolby, that's not a problem. AAC was co-developed by Dolby Labs and other partners. Apple had also partnered with them on bundling A.Pack, an AC-3 encoder, with earlier versions of Final Cut Pro. So I don't see any major hurdles to working with an established vendor to deliver multichannel surround of equal fidelity to DVD.

DTS would be more difficult to support but it's negligible since very little content is mastered in DTS and even at 768kbps, DTS is not perceptually transparent (indiscernible from uncompressed multichannel) whereas Dolby Digital is indeed perceptually transparent at lower bitrates due to various parameters and filters that reduce the bitrate requirements.
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Old Mar 22, 2007, 11:57 PM   #12
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I am somewhat new to what you're all saying. But if I can translate this to non expert. But where it seems to be right now is this. There is no way AppleTV can do 5.1 right now, but it might be possible down the line.

To me, there is absolutely ZERO point in owning something that doesn't have 5.1 sound. I can't even fathom how it got out of the development stage without being able to play 5.1 sound. It seems like right after they determined how to make it play HD they should figure out how to make it 5.1.

If you told me I could rip my Dvds into my computer and stream them to me AppleTV, I would cancel my cable and buy one of these things tomorrow. I would immediately buy all of my TV through itunes and watch my personal ripped dvds.

But without 5.1, what's the point?
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Old Mar 23, 2007, 02:12 AM   #13
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Almost all programs only support ripping DVd audio with stereo or mono.

Apple TV Video formats supported

* H.264 and protected H.264 (from iTunes Store): Up to 5 Mbps, Progressive Main Profile (CAVLC) with AAC-LC audio up to 160 Kbps (maximum resolution: 1280 by 720 pixels at 24 fps, 960 by 540 pixels at 30 fps)
* iTunes Store purchased video: 320 by 240 pixels or 640 by 480 pixels
* MPEG-4: Up to 3 Mbps, Simple Profile with AAC-LC audio up to 160 Kbps (maximum resolution: 720 by 432 pixels at 30 fps)
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Old Mar 23, 2007, 09:29 AM   #14
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Quote:
Originally Posted by davede70 View Post
To me, there is absolutely ZERO point in owning something that doesn't have 5.1 sound. I can't even fathom how it got out of the development stage without being able to play 5.1 sound. It seems like right after they determined how to make it play HD they should figure out how to make it 5.1.

But without 5.1, what's the point?
It isn't as bad as it sounds... yes, it doesn't do discrete 5.1 right now, but a ripped DVD with 5.1 AAC is properly downmixed for Dolby Pro Logic. It isn't /quite/ as good as discrete, but some of us had trouble telling the difference until we looked at exactly what our receiver was getting.

While it is still a bit disappointing, it does mean I can do something like archive a DVD using 5.1 AAC, and the Apple TV will still play it, even if the audio is 320Kbps... (The 160kbps limit is a bit of a lie by Apple, as is the 5Mbps limit, it is closer to 6Mbps).
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Old Mar 23, 2007, 09:42 AM   #15
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While it is a possibility, I wouldn't bet on it. Perhaps Apple will charge $2 for Dolby AC-3 encoder, but then again, iPod can theoretically playback WMA, Ogg Vorbis, etc. as well. But it doesn't.

As for Xbox 360, no, it does not generate AC-3 from AAC (since it does not support AAC). HD DVD does not use AAC either (it has Dolby E-AC-3 or Dolby Digital Plus, which is designed to convert easily into AC-3). For games, Xbox 360 generates AC-3 from Microsoft's own format via dedicated audio processor.
Re-read my post. I said "for HD-DVD discs that use Dolby's HD audio codecs". I am well aware of what the 360 can and cannot do. However, I didn't exactly say what I meant in a clear manner.

(As an aside, the 360 will playback your AAC music with an optional component. MS obviously doesn't want to pay for the license if it doesn't have to, especially with 'comparable' tech in-house)

Quote:
While your assumption may be possible, I wouldn't bet on Apple TV's 1 GHz Intel Pentium M to do that, especially while playing back 720p video. It would make more sense for Apple to license AC-3 for QuickTime and Apple TV instead of licensing Dolby Digital Live. Why tax Apple TV with converting 5.1 AAC (which it does not presently support) to AC-3 unnecessarily?
Slight correction, the Apple TV does support 5.1 AAC, it just downmixes it into stereo using Dolby Pro Logic. My receiver, at least, manages to maintain most of the surround, even if it isn't as good as discrete.
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Old Mar 23, 2007, 10:17 AM   #16
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According to an article at Anandtech, the audio chip inside the Apple TV is a Realtek ALC885.

Realtek's description of this chip is as follows: "The ALC885 is a high-performance 7.1+2 Channel High Definition Audio Codec with advanced lossless content protection technology that protects pre-recorded content while still allowing full-rate audio enjoyment from DVD audio, Blu-ray DVD, or HD DVD discs."

Apple? So whats the deal with not being able to play 5.1 on my Apple TV with an audio chip with this kind of horsepower?
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Old Mar 23, 2007, 10:33 AM   #17
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It seems from the description of the chip in aTV, 5.1 sound is certainly supported on the hardware side of things, but doesn't have any software support (yet.)

Furthermore, although aTV supports 720p videos, there are currently no such movies or shows available to purchase through the iTunes Store.

These are the two biggest gaps in the aTV. The hardware is there. The demand and interest is there. But the content isn't.
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Old Mar 23, 2007, 07:29 PM   #18
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ACC 5.1 encoded but no support in appleTV

Call me an optimist, but I just spent the last bit of time figuring out how to put together a quicktime 5.1 clip. The clip I ended up with: AAC, 6.0 (C L R Ls Rs Cs), 48,000 kHz. When I pull that up on the ATV - nice glorious Left and Right channels(not even a center channel). Very dissapointing.
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Old Mar 25, 2007, 04:34 PM   #19
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Interesting article about 5.1 on the Apple TV:

http://www.thismuchiknow.co.uk/?p=34

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Old Mar 25, 2007, 06:58 PM   #20
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It seems to me that, if you can hack the ATV to play Xvid video, you can use the same technique to play AC3 audio.
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Old Mar 28, 2007, 12:52 AM   #21
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fyi. I grabbed a DTS encoded wav, synced it onto a "testing" playlist on my appleTV and played it...

static for about 1/2 second, and then the glorious blue led stripe on my Sony receiver lit up and pushed through sound in DTS. Looks like it's doing the same thing my creative xFi is doing in my PC when it gets a DTS encoded signal: passing along a bitstream and letting the receiver do the work.

any reason that if i rip and encode into a multichannel sound format that itunes would support (is that the real issue?) that it wouldn't play me a 5.1 audio track along with a movie?
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Old Mar 28, 2007, 01:30 AM   #22
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From what i have heard if you can get it too play in surround on your mac in itunes it will play fine on the TV
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Old Mar 28, 2007, 01:37 AM   #23
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have tried ripping/encoding a couple of things with Handbrake, but iTunes (or anything else on my system atm) can't even play the file, so I haven't bothered syncing it. (tried ripping audio as AC3 stream)

looks like future handbrake stuff will allow 5.1 AAC, but no receiver i know about decodes that yet. Anyone know of anything that will let me encode a movie file (mp4 preferably) and have a straight DTS wave encoded in the stream?
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Old Mar 28, 2007, 09:05 AM   #24
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Quicktime (aka ATV media player) doesn't do pass-through audio (It will convert everything into PCM). As mentioned before Apple won't cough up the dough for a Dolby Digital Live license fee so when the ATV sees the AC-3 it doesn't know what to do with it. 5.1 AAC gets downsampled to Pro Logic (which is essentially matrix encoded stereo so that it will play as stereo on devices that can't support Pro Logic).

Hacked copy's of ATV running VLC player CAN play 5.1 AC-3 tracks (VLC player will just pass the audio on to the toslink and let the reciever handle it) but this is not a seemless option.

It has been rumored Apple is considering adding the ability for quicktime to do pass-through audio for AC-3 but at this time nothing has been done.
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Old Mar 28, 2007, 11:44 AM   #25
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So even if you add the AC-3 Codec in the quicktime folder on the ?TV it gets downmixed???
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