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smdewart
Mar 21, 2007, 02:33 PM
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!



Krevnik
Mar 21, 2007, 03:22 PM
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.

nutmac
Mar 21, 2007, 03:36 PM
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.

Krevnik
Mar 21, 2007, 03:38 PM
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.

princealfie
Mar 21, 2007, 03:39 PM
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?

Krevnik
Mar 21, 2007, 03:51 PM
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.

ces1965
Mar 22, 2007, 12:48 PM
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.

nutmac
Mar 22, 2007, 06:23 PM
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?

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.

sycho
Mar 22, 2007, 07:15 PM
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.

traderx1
Mar 22, 2007, 10:05 PM
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

Avatar74
Mar 22, 2007, 10:19 PM
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.

davede70
Mar 22, 2007, 11:57 PM
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?

nzvafds
Mar 23, 2007, 02:12 AM
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)

Krevnik
Mar 23, 2007, 09:29 AM
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).

Krevnik
Mar 23, 2007, 09:42 AM
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)


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.

CubFan74
Mar 23, 2007, 10:17 AM
According to an article at Anandtech (http://www.anandtech.com/mac/showdoc.aspx?i=2951&p=8), the audio chip inside the Apple TV is a Realtek ALC885.

Realtek's description (http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=138) 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?

job
Mar 23, 2007, 10:33 AM
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.

wezley
Mar 23, 2007, 07:29 PM
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.

maurj
Mar 25, 2007, 04:34 PM
Interesting article about 5.1 on the Apple TV:

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

- maurj.

daveL
Mar 25, 2007, 06:58 PM
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.

dawho1
Mar 28, 2007, 12:52 AM
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?

trainguy77
Mar 28, 2007, 01:30 AM
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 :apple: TV

dawho1
Mar 28, 2007, 01:37 AM
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?

Diode
Mar 28, 2007, 09:05 AM
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.

musicpenguy
Mar 28, 2007, 11:44 AM
So even if you add the AC-3 Codec in the quicktime folder on the ?TV it gets downmixed???

pickerin
Apr 1, 2007, 07:34 AM
According to an article at Anandtech (http://www.anandtech.com/mac/showdoc.aspx?i=2951&p=8), the audio chip inside the Apple TV is a Realtek ALC885.

Realtek's description (http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=138) 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?

Well, this is my first post to MacRumors and I figured I'd make a "rumor squasher".

The AppleTV most definitely plays Dolby DTS 5.1 audio, without any modifications or additional software.

This is a great article on support for 5.1 on Apple hardware, and I'm very surprised I haven't seen it more:

http://www.roughlydrafted.com/RD/RDM.Tech.Q1.07/147048D8-D8B7-45E7-9A97-3CD5B4C2B75A.html

If you'd like to hear glorious 5.1 audio (yep, front, center, and rear speakers, all playing different tunes). Download this DTS 5.1 surround sound reference file:

http://www.diatonis.com/downloads/diatonis_dts_wav_io_afos.zip

Unpack it, load it into your iTunes library and play it. It'll sound like static. That's because iTunes itself cannot decode it properly, so it is trying to downsample it.

The above file is available on this site, along with a different one, as well as other audio reference files:

http://www.diatonis.com/downloads_dts_ac3.html

After you have the reference file loaded into iTunes, the magic starts.

Just tell your AppleTV to sync the file. iTunes will copy it across.

Have your AppleTV play the file, and your DTS receiver will click over to DTS 5.1 surround and play the file on all 6 channels.

Over on the Handbrake forums, they're talking about how the latest build of Handbrake should be able to properly encode a DTS 5.1 audio track into a DVD rip. In theory, that'll mean those files will then play in 5.1 on an AppleTV.

Try this out yourself. Then spread the word. I think the AppleTV is getting a bad rap regarding audio when in fact it's just bad encoding.

-Rob

p.s. Here's the link to the Handbrake forums about it:
http://handbrake.m0k.org/forum/viewtopic.php?p=2649&sid=cf8ff6898c56826914fdbdefcdf58a84

pickerin
Apr 1, 2007, 07:34 AM
According to an article at Anandtech (http://www.anandtech.com/mac/showdoc.aspx?i=2951&p=8), the audio chip inside the Apple TV is a Realtek ALC885.

Realtek's description (http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=138) 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?

Well, this is my first post to MacRumors and I figured I'd make a "rumor squasher".

The AppleTV most definitely plays Dolby DTS 5.1 audio, without any modifications or additional software.

This is a great article on support for 5.1 on Apple hardware, and I'm very surprised I haven't seen it more:

http://www.roughlydrafted.com/RD/RDM.Tech.Q1.07/147048D8-D8B7-45E7-9A97-3CD5B4C2B75A.html

If you'd like to hear glorious 5.1 audio (yep, front, center, and rear speakers, all playing different tunes). Download this DTS 5.1 surround sound reference file:

http://www.diatonis.com/downloads/diatonis_dts_wav_io_afos.zip

Unpack it, load it into your iTunes library and play it. It'll sound like static. That's because iTunes itself cannot decode it properly, so it is trying to downsample it.

The above file is available on this site, along with a different one, as well as other audio reference files:

http://www.diatonis.com/downloads_dts_ac3.html

After you have the reference file loaded into iTunes, the magic starts.

Just tell your AppleTV to sync the file. iTunes will copy it across.

Have your AppleTV play the file, and your DTS receiver will click over to DTS 5.1 surround and play the file on all 6 channels.

Over on the Handbrake forums, they're talking about how the latest build of Handbrake should be able to properly encode a DTS 5.1 audio track into a DVD rip. In theory, that'll mean those files will then play in 5.1 on an AppleTV.

Try this out yourself. Then spread the word. I think the AppleTV is getting a bad rap regarding audio when in fact it's just bad encoding.

-Rob

p.s. Here's the link to the Handbrake forums about it:
http://handbrake.m0k.org/forum/viewtopic.php?p=2649&sid=cf8ff6898c56826914fdbdefcdf58a84

p.s.s. If you try it out and it works, or if you just believe me, please Digg this article and help get the word out (I didn't post it):
http://digg.com/apple/Ten_Myths_of_the_Apple_TV_5_1_Audio

iJon
Apr 1, 2007, 06:42 PM
I believe you can play 5.1 (AC-3) off the Apple TV if you perform a certain hack. This hack involves pulling out the hard drive, mounting it, copying a few files to the OS and then putting it back together. I use this file on my MacBook Pro to play HD movies with Dolby Digital EX and DTS with my audio reciever.

http://trac.cod3r.com/a52codec/

jon

also: I have never been able to get my MacBook Pro to output AC-3 to my reciever without the help of that codec. I see the article above states it isn't necessary but who knows. I'm a bit skeptical.

Yuvi
Apr 2, 2007, 01:54 AM
Unpack it, load it into your iTunes library and play it. It'll sound like static. That's because iTunes itself cannot decode it properly, so it is trying to downsample it.

iTunes isn't trying to downsample it; it's playing the file exactly as what it claims to be - 2 channel 16 bit linear PCM audio. It's crafted in such a way that when the data is played unmodified over a digital output, it almost matches the official spec on how to send DTS audio over S/PDIF connections (at least one bit is still set incorrectly, but most receivers ignore it.)

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.

Interesting, is there actually a codec-level technique that allows more efficient transcoding from AAC to AC-3 than simply decoding to PCM and re-encoding to AC-3, like there is for E-AC-3 to AC-3? My understanding of the two codecs was that they weren't similar enough for this.

Avatar74
Apr 7, 2007, 02:53 PM
Well, this is my first post to MacRumors and I figured I'd make a "rumor squasher".

The AppleTV most definitely plays Dolby DTS 5.1 audio, without any modifications or additional software.

This is a great article on support for 5.1 on Apple hardware, and I'm very surprised I haven't seen it more:

http://www.roughlydrafted.com/RD/RDM.Tech.Q1.07/147048D8-D8B7-45E7-9A97-3CD5B4C2B75A.html

If you'd like to hear glorious 5.1 audio (yep, front, center, and rear speakers, all playing different tunes). Download this DTS 5.1 surround sound reference file:

http://www.diatonis.com/downloads/diatonis_dts_wav_io_afos.zip

Unpack it, load it into your iTunes library and play it. It'll sound like static. That's because iTunes itself cannot decode it properly, so it is trying to downsample it.

The above file is available on this site, along with a different one, as well as other audio reference files:

http://www.diatonis.com/downloads_dts_ac3.html

After you have the reference file loaded into iTunes, the magic starts.

Just tell your AppleTV to sync the file. iTunes will copy it across.

Have your AppleTV play the file, and your DTS receiver will click over to DTS 5.1 surround and play the file on all 6 channels.

Over on the Handbrake forums, they're talking about how the latest build of Handbrake should be able to properly encode a DTS 5.1 audio track into a DVD rip. In theory, that'll mean those files will then play in 5.1 on an AppleTV.

Try this out yourself. Then spread the word. I think the AppleTV is getting a bad rap regarding audio when in fact it's just bad encoding.

-Rob

p.s. Here's the link to the Handbrake forums about it:
http://handbrake.m0k.org/forum/viewtopic.php?p=2649&sid=cf8ff6898c56826914fdbdefcdf58a84


You're getting things mixed up here... First, Dolby Digital and DTS are two different encoding systems. Second, there is currently no support for AC-3 in the AppleTV. Regardless of the fact that Handbrake/Mediafork has the ability to mux 5.1 AAC into the audio portion of an MPEG-4 AVC file, there's currently no means of transcoding 5.1 AAC to AC-3 in the AppleTV and your receiver will NOT recognize the 5.1 AAC bitstream.

The audio chipset in the AppleTV allegedly does support Dolby Digital Live which can transcode AAC to AC-3, but assuming it is the Intel HD Audio chipset, the Dolby Digital Live feature has not yet been enabled and there are no hacks out that have a demonstrated, verified ability to transcode and transmit AC-3 from the AppleTV.

Also, as much as I enjoy reading the philosophical rants at roughlydrafted, the guy doesn't know what the hell he's talking about when it comes to Dolby Digital vs. Dolby Surround. These are two entirely different formats.

Dolby Surround audio does indeed reside in most iTunes movies and DVD movies in the two front channels (L-R), but it is NOT a discrete 5.1 channel surround format. Dolby Surround is an analog stereo matrixed surround format whereby the information for the back surround channel(s) is phase shifted by 90 degrees and added to the main L-R audio. Because of the 90 degree phase shift, the surround information is not audible if played back through a conventional 2-channel system. But a Dolby ProLogic or Dolby Digital decoder will extract the phase-shifted analog signal from the main audio in a manner similar to a Fourier transform, and send the extracted analog matrix to the surround channel(s).

Dolby Digital has an improved dynamic range, various metadata parameters including dialogue normalization and Dynamic Range Control, which Dolby Surround does not possess. Additionally, as a discrete digital multichannel surround format, Dolby Digital does not experience the phase incoherence of Dolby Surround in which stereo and front-back separation range from less distinct to simply unintelligible.

Avatar74
Apr 7, 2007, 03:15 PM
Interesting, is there actually a codec-level technique that allows more efficient transcoding from AAC to AC-3 than simply decoding to PCM and re-encoding to AC-3, like there is for E-AC-3 to AC-3? My understanding of the two codecs was that they weren't similar enough for this.

Well, as I understand it, Dolby Digital Live is actually a hardware transcoder in the Intel HD Audio chipsets. There isn't much public documentation on the exact method of transcoding from AAC to AC-3 in Dolby Digital Live. However, my guess is that it doesn't involve decoding the signal to Linear PCM as AAC is fundamentally built upon many of the perceptual coding techniques in AC-3. Dolby was one of the major partners, along with Fraunhofer-IIS, that developed the AAC codec.

Forced Perfect
Apr 7, 2007, 05:18 PM
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.

Exactly. There's hardware support for 5.1 on the sound controller, however, it is not enabled in software. So until Apple decides to activate it we're stuck with 2 channel.

It probably won't be enabled until Apple starts selling movies with 5.1 on the Apple Store.

(If you're reading, please enable it before then, Apple!)

stompy
Apr 10, 2007, 12:16 PM
Also, as much as I enjoy reading the philosophical rants at roughlydrafted, the guy doesn't know what the hell he's talking about when it comes to Dolby Digital vs. Dolby Surround. These are two entirely different formats.


You should send him your corrections, he's usually happy to make updates on such things. (I've seen several links over to his blog, would be nice if all those readers got the straight story.)

iJon
Apr 11, 2007, 12:55 AM
Exactly. There's hardware support for 5.1 on the sound controller, however, it is not enabled in software. So until Apple decides to activate it we're stuck with 2 channel.

It probably won't be enabled until Apple starts selling movies with 5.1 on the Apple Store.

(If you're reading, please enable it before then, Apple!)
Once again, I'm going to have to bash this into the heads of people in this thread.

Hack your AppleTV either buy booting OS X or taking the hard drive out, drop this codec in the right folder and you have true 5.1, simple as that.
http://trac.cod3r.com/a52codec/

jon

GregA
Apr 11, 2007, 03:52 AM
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.

Apple has done something strange here. A system that is hardware capable of 5.1 surround but doesn't enable it, and a system which can play 720p but Apple doesn't sell anything HD.

I suspect we'll see an anouncement of support of both. Perhaps they'll charge $25 for 5.1 surround and bundle a couple of movies... just to get people buying. I wonder when it'll happen... at NAB? or WWDC?

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).It may not be a lie - Apple may know that the AAC->AC3 transcoding can only handle up to 160kbps. Or it may just be the quality Apple will sell at on the iTunes store.

weldon
Apr 11, 2007, 09:53 AM
Exactly. There's hardware support for 5.1 on the sound controller, however, it is not enabled in software. So until Apple decides to activate it we're stuck with 2 channel.
I'm not sure that this is the proper understanding of what the hardware support for 5.1 on the sound controller would do. The purpose of 5.1 support is to decode the digital stream into analog. 5.1 support in hardware is useless without 6 analog audio outputs. In fact, what you really want is for the hardware decoder to NOT TOUCH the audio stream at all and just pass it to the optical out so an external DAC (most likely in your A/V Receiver) can decode it.

Just to be clear, I don't think we need the AppleTV to decode the audio to get surround sound. If it does decode the audio to convert it from digital to analog, we would need separate analog outputs on the box. What we do need is for the hardware to NOT decode the audio stream and just bypass this to send the raw stream (DD or DTS) to an external receiver which would then decode into 5.1 sound.

If you don't have access to a surround sound receiver, then you still need the AppleTV to downmix the audio to 2-channel stereo because that is the only thing that your receiver would understand (over optical and/or analog). This is where the hardware support for 5.1 audio would actually come into play - to decode the signal into analog (and downmix to the two available channels).

The other possible use for hardware support would be to do real-time transcoding from one multi-channel audio format to another, but I think this is unusual and fraught with problems and out of scope for our current discussion.

weldon
Apr 11, 2007, 09:59 AM
The other possible use for hardware support would be to do real-time transcoding from one multi-channel audio format to another, but I think this is unusual and fraught with problems and out of scope for our current discussion.
Of course, as soon as I post I realize that I've ignored the very important and real possibility of transcoding 5.1 AAC in quicktime to DD.

I'll admit to ignorance here, are there any other multi-channel audio formats that are possible in AppleTV compatible files that would require transcoding to send to a reasonably current A/V receiver? AAC to AC3 is one - are there more?

cingularpat
Feb 12, 2008, 04:10 PM
So does any of this change with the release of the Take 2 update for Apple TV? I've been toying with mine all day trying to get something 5.1 out of it, but haven't gotten very far. HOWEVER! I can confirm that when it starts up and plays the opening video, I get Dolby Digital 3/2.1 on my Sony receiver, so it IS passing over something useful! Let's figure it out everyone!!!!

trainguy77
Feb 12, 2008, 05:35 PM
Well rip a DVD in 5.1 and give it a shot. :D I have a 50mb DTS wave file that someone could try too.

cingularpat
Feb 12, 2008, 08:00 PM
Tried some stuff that I already had ripped/converted into H.264 with 6-channel discrete. No luck. But I'm telling you, that opening video was in Dolby Digital somehow!!!

trainguy77
Feb 12, 2008, 11:14 PM
Tried some stuff that I already had ripped/converted into H.264 with 6-channel discrete. No luck. But I'm telling you, that opening video was in Dolby Digital somehow!!!

The odd part about that. If its encoded that means that the apple TV is converting it to 2 channel as otherwise it would just play as static.

cingularpat
Feb 13, 2008, 08:05 AM
The stuff I have is encoded with multi-channel AAC. The ATV appears to convert that to Dolby Pro Logic. My theory though is that something in there may be capable of converting AAC to Dolby Digital because of that startup video. When connected to a DD receiver, it plays in DD. But I'm sure if I had it hooked up through standard stereo RCA jacks, I would hear it in 2-channel glory. I've only had my ATV for a few days, so I don't know much about booting OSX on it or anything like that - otherwise I'd try to figure this out myself. I would imagine someone would have to boot OSX on it, find the video file that plays when it boots, and use movie inspector to find out what's going on. Any ideas??

knockturnal
Feb 15, 2008, 10:17 PM
[QUOTE=cingularpat;4956547]The stuff I have is encoded with multi-channel AAC. The ATV appears to convert that to Dolby Pro Logic. My theory though is that something in there may be capable of converting AAC to Dolby Digital because of that startup video. When connected to a DD receiver, it plays in DD. But I'm sure if I had it hooked up through standard stereo RCA jacks, I would hear it in 2-channel glory./QUOTE]

you stereo cannot decode multi channel AAC, thats why now matter what you try discreet, 5.1 aac or others you wont get Dolby Digital. look on your reciever and see what logos are on there. most likely all you can support is Dolby Digital, or DTS or some form of it. maybe if its newer you can get mp3 wma or other audio formats. i dont belive there is a home stereo with 5.1 aac though. maybe sony will have one soon since the ps3 supports it, i belive!?

anyways...the file has to be encoded with DD to get DD. hd is only available from the apple tv so its tricky to view the properties.

cingularpat
Feb 15, 2008, 10:31 PM
Yeah I know all that.

I guess with time it'll get figured out. I just figured since that opening video plays no matter what kind of TV/receiver you have it hooked to, that maybe there was something going on behind the scenes. ::sighs:: it's still a fun little device though.

QuarterSwede
Feb 15, 2008, 10:31 PM
As far as I understand, the new software refresh (Take 2) updates the AppleTV to play 5.1 DD. Because, seriously, Dolby Pro Logic is terrible compared to 5.1 DD or DTS. I remember thinking "it's about time Apple gets it" while watching the MWSF 2008 keynote.

knockturnal
Feb 16, 2008, 01:14 AM
Yeah I know all that.

I guess with time it'll get figured out. I just figured since that opening video plays no matter what kind of TV/receiver you have it hooked to, that maybe there was something going on behind the scenes. ::sighs:: it's still a fun little device though.

the video that starts up is probably 5.1 DD. the thing we need to know is what container the movies are supported in first of all. the fact that you cant downlaod them to your computer gets me. makes me think that something else is going on behind behind, way behind the scenes. "iTunes Store purchased video" from apple tech specs for ATV makes me think they're using a different container and dont want people to know, something that supports ac3. i used nero to make a .mp4 file with ac3 audio, wont play on ATV or PS3 but does on pc, so???

JasonKerner
Feb 16, 2008, 02:10 AM
Surround sound on the Apple TV has these following methods on the take 2 software...

The Apple rented movies have two soundtracks. They are in .MP4 format. They have an H264 video track, followed by a 'stereo' track and a 'surround' track. The stereo track is AAC 5.1. The Apple TV will output this as a muxed Dolby ProLogic signal - but heres the key thing - most amplifiers won't 'detect' a Dolby ProLogic signal, you'll just have to put your amp on that mode and see if it sounds better. Switching your amplifier to Dolby ProLogic is the thing to do here and have a listen. You could put any feed into a Dolby ProLogic amp and it would send some of the sounds to the rear speakers, so its not the same as a Dolby Digital signal.

The surround track in the Apple TV files is an AC3 digital stream, encoded in the Private stream of the MP4 file, making it a legal MP4. Private streams can contain pretty much what you want, but the public streams have strict rules to make it a legal file.

Why are the two sound tracks and how does the Apple TV know what to use, you ask? Well, AC3 can only be decoded by a Dolby Digital surround amplifier - so if this signal is sent to TV speakers or a stereo amp, you wouldn't hear anything - so thats why theres an AAC track too. For those people out there that don't have Dolby Digital decoders. In Take 2's menu, there is an option to turn Dolby Digital output on, when this is turned on, it looks for an AC3 track on the file playing, if it has one, it plays that.

So what options do we have for putting our on movies on there and play in Dolby Digital?

Visualhub 1.31 has an Apple TV 5.1 preset - using this, you could take a file and it would pass through the AC3 soundtrack and put it into a .mov container. Why .mov??? Because to get it into an mp4 as a private stream, along with a legal stereo AAC soundtrack is a bit more tricky presently. If you have a file that has an AC3 source, this works. If you have something that isn't, eg, a DTS file or AAC 5.1, it won't convert it to AC3 - it'll just make it stereo.

The guys over at Handbrake have got a SVN version that gets AC3 into the private stream of an MP4 file, its not a public release yet, but they're working on it.

If you try to play any of these files on your Mac, you'll need Perian 1.1 installed to take the AC3 and convert it to stereo so you can actually hear it on your speakers as not all of us have Dolby decoders plugged to our Mac and Quicktime doesn't output an AC3 via the optical connection anyway - only DVD Player does.

Does it work, you ask? Yes, I've converted a bunch of VOBs and MKVs with AC3 soundtracks and put my amplifier (Denon 1802) on Direct mode and it detects the AC3 feed and the display says Dolby Digital.

What about DTS? The Apple TV could play DTS as is by using it as a passthrough track and again, letting the amp decode it, but so far no one has made a conversion app to do this automatically, you'd have to rip it as a loseless AAC and then paste it in to your file manually to make this work - haven't tried it myself yet, but heard others do it.

Think thats pretty much it.

Jason

smilinmonki666
Feb 16, 2008, 04:47 AM
Cheers for that JasonKerner. So by my understanding, its not the best time to convert files as of yet until the guys at HB make a public version available to enble the .VOB to .MP4 conversion include the 5.1 private stream.

I've been clever & allowed my self time to just rip my DVD's to my PC as i'm waiting on my funds for a mac. I'm currently using DVD Decrypter. So I'm hoping when the time comes to be able to convert files to :a:TV file type with 5.1DD I will be able to que them up & leave my pc to do the work.

Why couldn't they just allow the :a:TV to playback .vob file types? When I was playing with Ubuntu a while back on my laptop, if i dragged the .vob file over to my HDD, I could watch a film straigh off? I know streaming via wireless, it wouldn't be feasable, not yet anyway, but surely via a gigabit wired network, it could work? That way, people would only have to worry about converting to iPod/iPhone products? A DVD bitrate isn't that high as a standard .vob file?

JasonKerner
Feb 16, 2008, 04:55 AM
Technically a DVD bitrate and a VOB file are the same thing. A film DVD disc as a VIDEO_TS folder and inside that will be a bunch of VOB files. DVD video is generally between 6-8Mbps (although it can go upto 10Mb as per the DVD spec).

The Apple TV has a 4Gb file size limit, so you'd have to pick a bitrate that generates a file less than 4Gb - this is pretty easy as the H264 codec is pretty efficient. Most of my DVD rips come out between 1.5-1.7Gb, HD rips are 3.74Gb.

If you've got a load of VOB files, you can use VisualHub to put everything in and throw out compatible Apple TV 5.1 files - this would produce .movs with an AC3 soundtrack - which work fine in the Apple TV. The only advantage of waiting for Handbrake with AC3 Mp4 support would be 1) tagging the files with metadata in MetaX for example rather than iTunes 2) if the Handbrake guys can get stereo AAC in there too, then you'd be able to play the same file on iPod/iPhone, etc... (as long as the resolution was supported by all). But if you've got a Mac with the Perian plugin and an Apple TV with a Dolby Amp wired to it - then I'd just use VisualHub as it does a few more formats than Handbrake.

Jason

smilinmonki666
Feb 16, 2008, 05:18 AM
Ok. So I use HB as i'm on PC Format, I use:

H.264
AAC with 6 Channel Descrete
and a bit rate of say 3000 for video

This would give me a video file with 5.1DD?

JasonKerner
Feb 16, 2008, 05:51 AM
if you used handbrake with those settings you wouldn't get Dolby digital, its going to create a file with six channel aac, a Dolby digital amp wouldn't know what that is. If you wanted prologic, those settings are fine, if you want 5.1 Dolby digital wait for the new version of handbrake.

To answer you earlier point about vob file playback, the apple tv won't do it as to get vob playback you have to have the dvd CSS encryption broken and apple won't do that

Jason

smilinmonki666
Feb 16, 2008, 05:57 AM
Ok, I'll wait for the new version. If I were to do it on my dads iMac? I would just use VisualHub?? Or would I need that plugin? I would just like a digital library but not loose anything, otherwise there is no point? With my iPod Touch, I'm not to bothered about watching a film on there? If I were to watch a film, I would convert it on the fly as I need them?

When do you suspect HB release their new version? I know its not the easiest thing to do but have they been working on it for a while?

& if I did do it on the iMac? What setting would you suggest to use to a 100% copy with 5.1? I'm going to download it now.

cingularpat
Feb 16, 2008, 08:03 AM
Another question I have, is what about stuff that I pull of my HD DVR? Normally I do H.264 at a bitrate around 6 Mbps with 6 channel AAC. So if I want to start layering these files to have the AAC for Mac playback and the AC3 stream directly from the cable feed, what would I have to do? Also, is that a bitrate that the ATV will like? I've noticed that so far, only 1 or 2 of my files show up on the ATV menu, so I'm assuming the bitrate is too high. Resolution is 1280x720, so I think that should be fine. I don't mind re-encoding what I've got if it will allow me to watch it on the Mac AND on the ATV.

What about converting the 6-channel AAC files I've got now into an ATV compatible version with AC-3? I hope that's a doable thing as well. Any help is greatly appreciated guys! I love this forum! :-)

sJv
Feb 16, 2008, 08:36 AM
What about converting the 6-channel AAC files I've got now into an ATV compatible version with AC-3? I hope that's a doable thing as well. Any help is greatly appreciated guys! I love this forum! :-)

Dolby Labs has very tight control over AC3 generation. Unless someone has hacked together something to generate AC3 (which would violate Dolby's copyright, and they are pretty uptight about that!), you will have to re-encode using your source material. The various encoding tools merely pass the original AC3 bitstream on, so if you lost it, you'll have to start from the beginning or you are out of luck.

-steve

mikeymoves
Feb 16, 2008, 10:07 AM
Dolby Labs has very tight control over AC3 generation. Unless someone has hacked together something to generate AC3 (which would violate Dolby's copyright, and they are pretty uptight about that!), you will have to re-encode using your source material. The various encoding tools merely pass the original AC3 bitstream on, so if you lost it, you'll have to start from the beginning or you are out of luck.

-steve

I don't know if this would work, but if you have Apple Compressor, you can extract the 6 aac files and re-encode them to ac3 in compressor by putting each track in its respective position. Not sure how this would work sync wise, but it would give you a 5.1 ac3

smilinmonki666
Feb 16, 2008, 01:29 PM
Ok then, I've done it. I can't wait to get a mac.

::::Heres a quick guide to rip your DVD (.VOB) to Apple TV 5.1 format in 2/3 simple steps:::

For those who already have one. This is the best way to do it in my opinion...

- - - -BEFORE YOU START THIS YOU WILL NEED TO ENSURE YOU HAVE A Dolby Digital Amplifer/ Speaker SET SO YOU CAN USE THE OPTICAL OUTPUT & ALLOW YOUR AMPLIFIER TO DECODE THE AC3 SIGNAL- - - -

Firstly you will need your purchased copy of the DVD(s) your going to have in your media library, then you need to download HandBrake (http://handbrake.fr/) & VisualHub (http://www.techspansion.com/visualhub/) which I'm affraid that the second peice of software you will need to purchase for about 13 or $24.

Now once they are downloaded & installed on your Mac you need to insert your DVD & load up HandBrake.

Then select the following options:

Format: Avi
Codecs: AVC/H.264 / AC-3 Audio

On the Video tab half way down the app box ensure the following:
FPS: Same as source(Then the FPS will show)
Encoder: x264 (h.264 Main)
Quality: This is entirely upto you as the user? As DVD is compressed already I would suggest you use the constant quality (I left mine at 100%, but apparently 85/90% works well for most, I'd go on the size & quality of your screen & cables.

On the Audio & Subtitles tab:
Track 1: (your language)(AC3)(5.1 ch)
Track 1 Mix: AC3 Pass Through

Then select where you wish for your file to be saved to & press 'GO'.

---------------------------

Once your DVD has finished encoding, load Visual Hub. Load your .AVI file(s) & add them the que.

Ensure you have the iTunes tab selected at the top of the screen and select the "Optimize For" drop down & select Apple TV 5.1 & tick H.264 Encoding. Again, the quality is up to you. but I personally would select the "Go Nuts". Select the save to folder & again, press "GO"!!!

Once thats finished, your done!!! Now, sync or stream to your :apple:TV & your away.

However, there is one more step you could do. Use MetaX (http://www.kerstetter.net/page53/page54/page54.html) to tag all your films/ programs for more detailed info & cover art for cover flow as demonstrated nicely by "billabong" (http://att.macrumors.com/attachment.php?attachmentid=90810&d=1194642862). This program is simple to use & you can either use the IMdb site to find all the info (Which has a link within the program to find the film your looking for.

Hope you all enjoy... & good luck.

- - - - Remember, it is illegal & unfair to use pirated material, always use your own. That way, if your computer was to meltdown, get stolen or contract a virus, you always have the original. - - - -

JasonKerner
Feb 16, 2008, 01:36 PM
Surely this method takes twice as long as you've got to run it through handbrake then visualhub - why not just drag the VIDEO_TS folder in to Visualhub, put it on the Apple TV 5.1 setting and let it do it all straight from the DVD source?

Jason

sJv
Feb 16, 2008, 02:29 PM
Surely this method takes twice as long as you've got to run it through handbrake then visualhub - why not just drag the VIDEO_TS folder in to Visualhub, put it on the Apple TV 5.1 setting and let it do it all straight from the DVD source?

Yup - you don't want to run it through Handbrake AND Visual Hub. Use ripping software like Mac the Ripper to decrypt CSS and place the TS folder on your hard drive. Then drag the TS folder into VH and you are done.

I believe Handbrake is on the more correct track, though, and should have a release soon. The nightly build is close. HB also gives you chapter markers, VH doesn't.

Both are great software - I bought a copy of VH to support the author, and I would donate money or beer to the HB team if they had that set up!

-steve

smilinmonki666
Feb 16, 2008, 05:53 PM
I maybe being dumb, but I tried that 3 times with Black Hawk Down, used Mac The ripper to decrypt the disc then dragged it into VH but it came out with the wrong audio track, tried this on a few discs on both Mac & PC and both do the same on different software?

Any suggestions folk?

smilinmonki666
Feb 17, 2008, 05:01 AM
Ok, so i've done what you suggested, & I've got it in my iTunes Library & it plays fine within iTunes, no sound due to the audio codec being AC3 passthrough, so thats cool.

I've sync'd with my :apple:TV & nothing happened, apart from "Unrecognised File Format"????

Whys that then? Can anyone suggest what I've done wrong? I'm trying it with another DVD at the moment just got to wait for VH to finish the file conversion.

smilinmonki666
Feb 18, 2008, 03:49 PM
ok, so I've managed to get my films done using mac the ripper then visualhub to convert the .vob to a .mov with ac3 pass through. Sync'd to my :apple:TV and the results were really impressive. One issue I've been getting is that ice ripped & converted "the Incredibles" on the "go nuts" setting on VB and found that the :apple:TV takes. Few minutes loading the cover art, loading the movie & then loading the menu again yet plays the movie fine. However, Black Hawk Down causes no problems and was converted on the High quality setting in VB. Has anyone ever had this problem. Its :apple:TV v2.0 I'm using if that helps.

Cheers

skrutzen
Feb 19, 2008, 12:50 PM
I had a thread about this last week and I still don't seem to have my question answered.

So here it is:
Suppose I use Mac the Ripper to extract my dvd, what setting do I use? Full disc extraction? Title extraction?

Then when I go to use use Visual Hub, what files specifically do I drop in there? Everything in the TS_Video folder? Or, just select files?

Now I've tried multiple things and cannot seem to get it to work. Also, I dragged all files from a full disc extraction to Visual Hub, and it said it would take 16 hours for file 1! Is that really how long it takes?

I would appreciate if someone could post a step by step tutorial for using Mac the Ripper and Visual Hub to get 5.1 audio for my dvd rips.

I might mention also, that I'm using the trial version of Visual Hub because I don't want to spend the money if it doesn't work for me, but I would be more than happy to give them my money if the program works! Other than the 2 minute restriction, are there any other limitations to the trial?

Thanks for helping a newbie!

smilinmonki666
Feb 19, 2008, 12:57 PM
I had a thread about this last week and I still don't seem to have my question answered.

So here it is:
Suppose I use Mac the Ripper to extract my dvd, what setting do I use? Full disc extraction? Title extraction?

Then when I go to use use Visual Hub, what files specifically do I drop in there? Everything in the TS_Video folder? Or, just select files?

Now I've tried multiple things and cannot seem to get it to work. Also, I dragged all files from a full disc extraction to Visual Hub, and it said it would take 16 hours for file 1! Is that really how long it takes?

I would appreciate if someone could post a step by step tutorial for using Mac the Ripper and Visual Hub to get 5.1 audio for my dvd rips.

I might mention also, that I'm using the trial version of Visual Hub because I don't want to spend the money if it doesn't work for me, but I would be more than happy to give them my money if the program works! Other than the 2 minute restriction, are there any other limitations to the trial?

Thanks for helping a newbie!

Hi skrutzen,

Heres a quick tutorial for you, on how I do it.

Using Mac The Ripper, extract full disc.

Once thats done, open up visual hub, click on the desktop and press 'CTRL' + 'Up Arrow'. This will bring up a window, find where the TS_Folder for that film is located and drag the TS_FOLDER, not the files, but the actual folder.

Next step is to make a choice. If you have an AV Reciever that can decode AC3, select the preset 'AppleTV 5.1', otherwise select the 'AppleTV' preset;
The difference between the 2 is that AppleTV 5.1 will allow AC3 passthrough to be present on the .mov file but no other audio so you will not be able to hear it on you mac (Unless you download Perion 1.1) or anything connected to your appleTV via the HDMI or Stereo out jacks.

This should work no problem.

Hope this helps. Anyprobs, let me know.

JasonKerner
Feb 19, 2008, 12:58 PM
Here's the definitive answer for 5.1 AC3 (not AAC!) sound on Apple TV.

From DVD Source
Use the yet-to-be released Handbrake. If you're feeling brave and can follow instructions, download the Source code and compile a version yourself. Use the H264 + AAC + AC3 preset. This will create an MP4, with a stereo (Dolby ProLogic muxed) and a AC3 Dolby Digital surround track.

From a file source (non-DVD, eg, AVI, MKV)
If it has an AC3 track currently, use the Apple TV 5.1 preset. This will produce a .mov file with a single AC3 audio track. It won't convert AAC 5.1 or DTS to AC3 - those will become stereo.

In both cases, to actually hear 5.1 Dolby, you'll need a 1) Dolby Digital amp 2) the Apple TV connected to that with an optical cable, or HDMI to that amp 3) Dolby Digital option turned on in the Apple TV v2 settings

Its that simple

Jason

sJv
Feb 19, 2008, 02:33 PM
This is for Leopard users. Download Handbrake 0.9.2 from here:

http://handbrake.fr/

optional: Rip DVD's to hard drive first using Mac The Ripper. While handbrake for Mac can rip and encode, it is nice to rip up a bunch of DVD's, then queue them up in handbrake to run overnight.

Fire up handbrake. Point it to your DVD or your hard disk with the first ripped movie to encode. 

Select the Destination you want the file to be encoded to. I be sure to use an m4v suffix - HB wants to name it .mp4 for some reason. Chapter markers only work with files that end in .m4v. You can always rename it later if you forget.

Under Codecs: select AVC/H.264 Video/ AAC + AC3 Audio.

Hit Start.

You can queue up more movies by selecting Source, making sure the destination and file name is what you want, select the codec, and Add to Queue.

Use MetaX to tag your movies when done.

The above settings work great on action movies. If you want to save space with an older or lower quality movie, you can lower the bit rate to 2000, and select ProLogic II in the Codec settings.

The nice thing about Handbrake with the new AAC + AC3 setting is that it will pass AC3 to your surround sound receiver, or play stereo via the RCA jacks if you dont' have a receiver. It will not play on your iPod or iPhone, though. I find it best to encode separately for those devices as you can fit 4X more movies on your device due to the more tuned file size.

-steve

uva25
Feb 19, 2008, 03:19 PM
This is for Leopard users. Download Handbrake 0.9.2 from here:

http://handbrake.fr/

optional: Rip DVD's to hard drive first using Mac The Ripper. While handbrake for Mac can rip and encode, it is nice to rip up a bunch of DVD's, then queue them up i Queue.

How quick is it to rip an average dvd with MTR? I would agree that it would be nice to get an overnight queue.

Jeff Hall
Feb 19, 2008, 03:21 PM
How quick is it to rip an average dvd with MTR? I would agree that it would be nice to get an overnight queue.

Depends on your DVD drive. With my external Pioneer (flashed to 111L firmware) the average full rip takes about 10-20 minutes. Encoding takes 3-4 hours on my MBP Core Duo 2.16GHz (Handbrake/Apple TV presets; 2-pass non turbo with "Slower" de-interlace mode).

uva25
Feb 19, 2008, 03:32 PM
Depends on your DVD drive. With my external Pioneer (flashed to 111L firmware) the average full rip takes about 10-20 minutes. Encoding takes 3-4 hours on my MBP Core Duo 2.16GHz (Handbrake/Apple TV presets; 2-pass non turbo with "Slower" de-interlace mode).
Thanks. What format should I rip the files using MTR. I will try a few tonight. It sounds like I should keep the ripped files as well as the M4P files that come from Handbrake? If so, that will be taking up a lot of space.

sJv
Feb 19, 2008, 03:37 PM
Thanks. What format should I rip the files using MTR. I will try a few tonight. It sounds like I should keep the ripped files as well as the M4P files that come from Handbrake? If so, that will be taking up a lot of space.

I didn't think MTR gives you a choice of formats. It merely makes a copy of what's on the DVD - minus the CSS encryption. You basically get a TS_VIDEO folder that you point HB (or Visual Hub if desired) to.

If you have the DVD's in question, I don't believe you need to keep the TS_VIDEO folders around on your hard drive after encoding, unless you want a backup. If something better comes along, you can just rip the movies again.

-steve

billabong
Feb 19, 2008, 05:12 PM
Will the AAC + AC3 playback on my iPhone or iPod touch? I want to rip for my AppleTV + iPod but have 5.1 is that possible? Does it just use the AAC audio when on the iPod and the AC3 when on the AppleTV?

knockturnal
Feb 20, 2008, 03:00 AM
Will the AAC + AC3 playback on my iPhone or iPod touch? I want to rip for my AppleTV + iPod but have 5.1 is that possible? Does it just use the AAC audio when on the iPod and the AC3 when on the AppleTV?

yes! i have one file that play on my iphone, and DD on apple tv.

in the presets on the right select "iPod-High Rez" then change the audio encoder to AAC+AC3, make sure file name your saving as ends in .m4v, if you uncheck then recheck "create chapter markers" i does it or you can type it. those are the only settings ive played with. the quality of video on my 52" is equal to slighty less than DVD, and i mean slightly. but having one file that plays on both iphone and apple tv with ac3/DD support is worth it!!

(DVD rez is only 720x480 anyways, these settings 640x420, so not a big deal)

trainguy77
Feb 20, 2008, 07:06 PM
Handbreak was updated to support this.

paolobr8
Nov 12, 2008, 12:17 PM
If you unplug and plug again your atv, you will have a 30 seconds movie with something like flying televisions. During all this movie my amplifier (my apple tv is connected with the denon amplifier through hdmi plug) shows that the sound coming out is dolby digital. This means that atv is supporting 5.1 audio.
How come I'm able to see my movie only stereo then, even if I rip a movie with handbrake in dolby digital?
Thanks 4 your attention!
Paolo

Krevnik
Nov 12, 2008, 12:20 PM
How come I'm able to see my movie only stereo then, even if I rip a movie with handbrake in dolby digital?


Cause you are doing it wrong. :P

Seriously though, you need to select the option for Handbrake to create an AC3 track. That is the Dolby Digital you are thinking of. AAC 5.1 isn't. Neither is Dolby Surround or Dolby Pro Logic II.

dynaflash
Nov 12, 2008, 01:31 PM
Cause you are doing it wrong. :P

Seriously though, you need to select the option for Handbrake to create an AC3 track. That is the Dolby Digital you are thinking of. AAC 5.1 isn't. Neither is Dolby Surround or Dolby Pro Logic II.
Exactly.
To test: click on the built in AppleTV preset. Change whatever you want but DO NOT mess with the audio.

You will get Dolby D just like on that startup video (where do you think we reverse engineered it from?) .

On an atv not hooked to a Dolby D capable receiver or an ipod or what-not it will just use the two channel dpl2 aac track.

rhett7660
Nov 12, 2008, 04:50 PM
This is for Leopard users. Download Handbrake 0.9.2 from here:

http://handbrake.fr/

optional: Rip DVD's to hard drive first using Mac The Ripper. While handbrake for Mac can rip and encode, it is nice to rip up a bunch of DVD's, then queue them up in handbrake to run overnight.

Fire up handbrake. Point it to your DVD or your hard disk with the first ripped movie to encode. 

Select the Destination you want the file to be encoded to. I be sure to use an m4v suffix - HB wants to name it .mp4 for some reason. Chapter markers only work with files that end in .m4v. You can always rename it later if you forget.

Under Codecs: select AVC/H.264 Video/ AAC + AC3 Audio.

Hit Start.

You can queue up more movies by selecting Source, making sure the destination and file name is what you want, select the codec, and Add to Queue.

Use MetaX to tag your movies when done.

The above settings work great on action movies. If you want to save space with an older or lower quality movie, you can lower the bit rate to 2000, and select ProLogic II in the Codec settings.

The nice thing about Handbrake with the new AAC + AC3 setting is that it will pass AC3 to your surround sound receiver, or play stereo via the RCA jacks if you dont' have a receiver. It will not play on your iPod or iPhone, though. I find it best to encode separately for those devices as you can fit 4X more movies on your device due to the more tuned file size.

-steve

So is this group pretty much in agreement that this is pretty much the way to go if you want 5.1 sound?

Question:

If you don't want to que up a bunch of movies via a MTR rip, can you still do it just using hand brake?

Thanks

FF_productions
Nov 12, 2008, 05:03 PM
So is this group pretty much in agreement that this is pretty much the way to go if you want 5.1 sound?

Question:

If you don't want to que up a bunch of movies via a MTR rip, can you still do it just using hand brake?

Thanks

Of course you can just use the dvd disc straight to handbrake, or even open several instances of Handbrake, I used to rip up to 3 movies at the same time.

rhett7660
Nov 12, 2008, 05:11 PM
Of course you can just use the dvd disc straight to handbrake, or even open several instances of Handbrake, I used to rip up to 3 movies at the same time.

Thanks.... That is what I was hoping for.

Great thread by the way.

paolobr8
Nov 13, 2008, 06:03 AM
Cause you are doing it wrong. :P

Seriously though, you need to select the option for Handbrake to create an AC3 track. That is the Dolby Digital you are thinking of. AAC 5.1 isn't. Neither is Dolby Surround or Dolby Pro Logic II.

Thanks. Today I learnt something new!

paolobr8
Nov 20, 2008, 03:12 AM
thank to Krevnik, I can see my movies in dolby digital on my atv.
Now I tried to set up handbrake with two audio tracks, let's say italian on track 1 and english on track 2, both with dolby digital.
I can see and change both tracks on itunes on my imac but I can see the same movie only in english on the atv.
Actually, I can see the both languages on the atv, but on the italian track the movie has no sound.
Where am I wrong?
Ciao.
paolo

uva25
Nov 20, 2008, 07:50 AM
I am very confused. Is it confirmed that the new update now makes movies 1) ripped with Handrake to an apple tv preset and 2) converted using VH using apple tv preset unusable?

weldon
Nov 20, 2008, 10:59 AM
I am very confused. Is it confirmed that the new update now makes movies 1) ripped with Handrake to an apple tv preset and 2) converted using VH using apple tv preset unusable?
There is a problem with encodes that only have a DD5.1 audio track and no AAC track. Files that have both AAC and DD5.1 work fine. If you're using the AppleTV preset in Handbrake (which encodes both audio tracks by default) you should be fine.

kiranmk2
Nov 20, 2008, 11:09 AM
thank to Krevnik, I can see my movies in dolby digital on my atv.
Now I tried to set up handbrake with two audio tracks, let's say italian on track 1 and english on track 2, both with dolby digital.
I can see and change both tracks on itunes on my imac but I can see the same movie only in english on the atv.
Actually, I can see the both languages on the atv, but on the italian track the movie has no sound.
Where am I wrong?
Ciao.
paolo

I can't speak for the new 2.3 firmware, but on 2.2 and older the ATV could only cope with one AC3 track per file.

Nimiety
Nov 20, 2008, 05:09 PM
What about files encoded with Visualhub on the "Apple TV 5.1 + 2.0" preset?

This presumably duplicates the handbrake setting, since it's clearly indicating two audio streams in the same format. Call me paranoid, but I just wanted to be absolutely sure with 250+ movies and 650+ tv shows in my library, 95% of which recorded either with the handbrake 0.9.2 profile or the visualhub profile... :)

NightStorm
Nov 20, 2008, 06:17 PM
What about files encoded with Visualhub on the "Apple TV 5.1 + 2.0" preset?

This presumably duplicates the handbrake setting, since it's clearly indicating two audio streams in the same format. Call me paranoid, but I just wanted to be absolutely sure with 250+ movies and 650+ tv shows in my library, 95% of which recorded either with the handbrake 0.9.2 profile or the visualhub profile... :)

It certainly did not.

Nimiety
Nov 20, 2008, 06:49 PM
It certainly did not.

So that means VH converted files have no audio at all, or does it mean they don't have 5.1 audio but still have the 2 channel stereo audio?

Is it all files touched by VH, or just those in a .mov container, meaning that the .mp4 containered converted files still work?

GregA
Nov 20, 2008, 10:29 PM
I am very confused. Is it confirmed that the new update now makes movies
1) ripped with Handrake to an apple tv preset and
2) converted using VH using apple tv preset unusable?

Note that VH has 3 choices for appleTV
1) AppleTV (which is an MP4 I think, with 2 channel AAC audio)
2) AppleTV 5.1 (which is a MOV, with 5.1 channel Dolby Digital audio only - if your amp can't handle the dolby digital surround then you get no sound)
3) AppleTV 5.1+2.0 (which is an MP4 with 5.1 Dolby Digital AND 2.0 AAC audio)

People are saying that files made like #2 do NOT work with the new AppleTV update.

Nimiety
Nov 21, 2008, 07:10 AM
Note that VH has 3 choices for appleTV
1) AppleTV (which is an MP4 I think, with 2 channel AAC audio)
2) AppleTV 5.1 (which is a MOV, with 5.1 channel Dolby Digital audio only - if your amp can't handle the dolby digital surround then you get no sound)
3) AppleTV 5.1+2.0 (which is an MP4 with 5.1 Dolby Digital AND 2.0 AAC audio)

People are saying that files made like #2 do NOT work with the new AppleTV update.


GregA - thank you - this is exavtly what I'm looking to confirm. The new version (SVN only) of handbrake will convert avi's but it is very unstable and crashed every time on my system, so visualhub is still the best (and by far the easiest) choice to bring on new content like that into the AppleTV on a Mac. I just want to be sure that the 650+ TV shows I have already converted aren't all going to be audio-free. :)

knockturnal
Nov 21, 2008, 10:34 AM
use handbreak, select ipod high rez default settings, and change audio to AC3+AAC, you have a file that will play on ATV, iphone, and ipods. there is no point really to increase the resolution of a ripped dvd or other file, you end up with the same quality, but a larger file size

Nimiety
Nov 21, 2008, 10:52 AM
use handbreak, select ipod high rez default settings, and change audio to AC3+AAC, you have a file that will play on ATV, iphone, and ipods. there is no point really to increase the resolution of a ripped dvd or other file, you end up with the same quality, but a larger file size

The problem is that handbrake doesn't (yet officially) support encoding mkvs or avis, only dvd sources. Also, handbrake isn't as streamlined by automagically adding files into itunes. Maybe not a problem for some, but when you're converting 20-30 files a week, saving that extra step helps.

brettatredback
Feb 28, 2009, 05:27 PM
Hi all - along the same line here - what about the case of wanting to use visualhub to convert .avi files to itunes format?

I am not sure how to check what audio tracks are in video file. Does anyone know? Let's for now, assume it is just stereo.

So, when converting in visualhub, i would just select the 'appletv' preset? Only would i select the appletv5.1 or appletv5.1+2.0 if i knew that the .avi's contained a surround sound track right? So, again if anyone can tell me how to check what audio tracks the .avi's have, that would be much appreciated.

thanks.

weldon
Feb 28, 2009, 08:14 PM
I would consider using Handbrake (which also has presets for AppleTV). The latest version of Handbrake can take AVI files as input, and it supports creating files with both a stereo and surround sound track that work with computers, iPods and the AppleTV.

brettatredback
Mar 1, 2009, 12:21 AM
I have found handbrake very buggy (Crashes) for video conversions....

On the topic of copyright protections, i assume there are some dvd's HB can't rip and only say MTR can? There is a great automated ripping script in this forum, but i see not much use for it since it doesn't make use of something like MTR...The first dvd i tried from my collection (the pianist) had bad sectors at the end, so assume the rip is useless.

Brett

realityking
Mar 1, 2009, 10:42 AM
You mean the 'Automating DVD Backup with FairMount, HandBrake and iTunes' threads? You know what Fairmout is?

brettatredback
Mar 1, 2009, 11:51 AM
yes, those are the threads i mean.

In hindsight, it was actual bad sectors on my first dvd! Even MTR said so!:). Just off to a bad start! I read a bit more about fairmount. Guess it should work great except for those dvd's that have a certain ARccOS protection. When i come (if) that, i guess i'll use MTR or something.

thanks.
Brett

weldon
Mar 1, 2009, 01:04 PM
I've done a couple hundred DVDs with Handbrake now and it works reliably for me. The only problem I've had is with certain Disney titles where I just rip and encode directly in Handbrake rather than go through a ripper first. I use DVDFab on Windows and RipIt.app on Mac.

HiFiGuy528
Mar 27, 2009, 12:37 AM
So does the new Handbrake 0.9.3 "universal" setting push AC3 5.1 surround to Apple TV via optical to receiver?

NightStorm
Mar 27, 2009, 07:33 AM
So does the new Handbrake 0.9.3 "universal" setting push AC3 5.1 surround to Apple TV via optical to receiver?

Yes.