Apple TV and 5.1 support - some definitive answers

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Berylium
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Post by Berylium »

loyalty_anchored,

I stand corrected on the Con I mentioned in my first option. That's very interesting news about the progress of ATVFiles. And while it would help my situation (if I could just get my AppleTV to boot from my external drive past the Apple logo, dang it) the difficulty of installing plug-ins is still beyond the average user. And while ATVLoader is wonderful for installing new plug-ins you must already have hacked your AppleTV which, again, precludes the average user.

The value of Dolby PLII as a substitution for a true, discreet audio source is obviously subjective but I agree with you completely. Hearing them one after the other shows, quite clearly, the wild superiority of AC3 - to my ears at least.

-Berylium
loyalty_anchored
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Post by loyalty_anchored »

@Berylium:

I must agree that the current work that needs to be done to enable SSH and install Loader is too much for the average joe, but i have heard things, and ready things...

Once the first update from apple gets pushed out to ATV, the hacking can begin :-) the update can be reverse engeneered to include Loader and be applied as easely as downloading the hack, and running it from a machine that is on the same network as the ATV and voila!

This is all speculation from information i have seen here and there, so its not 100% but i think it will happen fairly soon, at which point i could ask my dog to install ATV plugins in exchange for a milkbone :-)

Shoot me an IM and I can try to help you to boot OSX on your ATV, I was able to do it and i recall running into the same issue you are finding.

Sorry to everyone, if this post is a little bit off topic :oops:
jelockwood
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Post by jelockwood »

Berylium wrote:josephlew1s,
2. Get true, 5.1 discreet audio by tricking iTunes

This method allows you to get the discreet, 5.1 digital audio you’re looking for without hacking your AppleTV while keeping both the AppleTV Movies interface as well as the management of your library through iTunes. Sounds perfect, right? Well, it’s a pain in the ass. The exact method and steps required are discussed at length in this forum topic so I won’t repeat them in detail. Glossing over the process, you first encode your movie with HandBrake using an MP4 container. Then your use a tool that strips the AC3 audio track from the DVD and another to transcode the AC3 into a DD-WAV. Then you use QuickTime to encode the DD-WAV into ALAC (Apple Lossless). Finally, you open your movie’s .MP4 file in QuickTime, delete the audio track inserted by HandBrake, insert the ALAC audio soundtrack, and save to a .MOV file. Potential stumbling blocks include audio possibly being out of sync and that this trick only works with a 44.1khrtz audio and not the usual 48khrtz found on DVDs so there’s an extra step in the process of doing that conversion. Once you get a movie made this way you’re all set.

Pros:
  • - You get a true, discreet 5.1 channel audio experience from your movies (though, arguably, with a very slight loss in quality)
  • - You get to manage your movies through the default iTunes and AppleTV interfaces
Cons:
  • - The creation process is onerous at best.
  • - Your movies can only be played by an AppleTV connected to a receiver. Connecting your AppleTV directly to a television would result in screeching audio static because a TV can’t decode the digital audio stream.
  • - File size is increased by 300-400 megabytes due to the lossless audio
-Berylium
As far as I can see the above option pretty much needs QuickTime only to implement (after you have the AC3). Therefore it would seem quite possible for HandBrake to be upgraded to offer this as a built in option. Any comments from anyone else regarding this?

For what its worth, I am very disappointed with QuickTime's abysmal support for surround sound, subtitles, and alternate sound tracks. As such rather than an AppleTV I am considering a Mac mini running Front Row 2.0 (as will be included in Mac OS X 10.5). According to reports, this adds the ability to play VIDEO_TS folders which are played via the DVD Framework and not the pitiful QuickTime library. As the DVD Framework does properly support surround sound etc. this gives the desired result.

The AppleTV is not a completely useless device, it is by far the easiest to set up and use in its class (no surprise it is from Apple after all), but it cannot even manage DVD levels of expectations let alone HD DVD or Blu-ray (I am not just talking about video resolution). So much for it being the DVD player for the Internet age.

I really don't know how Apple are getting away with an almost complete lack of support for subtitles, I would have thought they would have been sued to oblivion over this by now (after all the USA is the land of lawsuit).
jbrjake
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Post by jbrjake »

jelockwood wrote:As far as I can see the above option pretty much needs QuickTime only to implement (after you have the AC3). Therefore it would seem quite possible for HandBrake to be upgraded to offer this as a built in option.
And you are basing this assessment on what, exactly?

How do you propose a cross-platform, GPL'd piece of software should encode audio to Apple's proprietary lossless format?
jelockwood
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Post by jelockwood »

jbrjake wrote:
jelockwood wrote:As far as I can see the above option pretty much needs QuickTime only to implement (after you have the AC3). Therefore it would seem quite possible for HandBrake to be upgraded to offer this as a built in option.
And you are basing this assessment on what, exactly?

How do you propose a cross-platform, GPL'd piece of software should encode audio to Apple's proprietary lossless format?
Handbrake is already able to output files which include 5.1 AAC sound which is aimed at an Apple environment and could be considered an Apple proprietary standard. Therefore how would it be any different to outputting to another slightly different Apple targetted format?

If you are referring to the fact that Handbrake uses open source libraries to do its work which cannot output this format, then this is why I suggested Handbrake could ask QuickTime to do this particular task. Handbrake is typically only ever going to be used on computers that already have QuickTime installed on after all. QuickTime is cross platform and Apple do provide an SDK for it. Obviously, in this scenario Handbrake would check for the remote possibility of QuickTime not being available and if not this proposed option would then be disabled.
nightstrm
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Post by nightstrm »

jelockwood wrote:
jbrjake wrote:
jelockwood wrote:As far as I can see the above option pretty much needs QuickTime only to implement (after you have the AC3). Therefore it would seem quite possible for HandBrake to be upgraded to offer this as a built in option.
And you are basing this assessment on what, exactly?

How do you propose a cross-platform, GPL'd piece of software should encode audio to Apple's proprietary lossless format?
Handbrake is already able to output files which include 5.1 AAC sound which is aimed at an Apple environment and could be considered an Apple proprietary standard. Therefore how would it be any different to outputting to another slightly different Apple targetted format?

If you are referring to the fact that Handbrake uses open source libraries to do its work which cannot output this format, then this is why I suggested Handbrake could ask QuickTime to do this particular task. Handbrake is typically only ever going to be used on computers that already have QuickTime installed on after all. QuickTime is cross platform and Apple do provide an SDK for it. Obviously, in this scenario Handbrake would check for the remote possibility of QuickTime not being available and if not this proposed option would then be disabled.
No, that is completely wrong. AAC is a standardized audio codec that can be used on any OS without the need of one piece of Apple software. I'm not even sure if Apple had any significant role in its development. AAC != Apple.

Also, Quicktime is not available for Linux, so it could not be used in the Linux port of HB. Plus, Quicktime does not take advantage of a lot of the advanced features found in x264.
jbrjake
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Post by jbrjake »

jelockwood wrote:Handbrake is already able to output files which include 5.1 AAC sound which is aimed at an Apple environment and could be considered an Apple proprietary standard.
Oh my god. Simply no.

And the idea of rewriting HandBrake with platform-specific modifications just to be a frontend to a proprietary API for a closed-source codec so the tiny minority of users with AppleTVs who are too lazy or inept to install Perian can get slightly better sound? Good luck with that.
sadcaper
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Post by sadcaper »

Well, has there been any updates on this subject? I am looking to get 5.1 out of my unhacked ATV, but can't seem to find all the programs required. Could someone possibly host some files for all us peons out here that can't find them ourselves? That would make this MUCH easier and we could create a FAQ of some sort that would make this process doable.

Let's help each other get a process together! I read the Garcias one, but let's get the programs together too. I think that would help out tremendously.

Thanks!
MichaelLAX

Post by MichaelLAX »

sadcaper wrote:Well, has there been any updates on this subject? I am looking to get 5.1 out of my unhacked ATV, but can't seem to find all the programs required. Could someone possibly host some files for all us peons out here that can't find them ourselves? That would make this MUCH easier and we could create a FAQ of some sort that would make this process doable.

Let's help each other get a process together! I read the Garcias one, but let's get the programs together too. I think that would help out tremendously.

Thanks!
For us lazy and inept unhacked Apple TV users, dated but still relevant:

http://www.thismuchiknow.co.uk/?p=34
sadcaper
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Post by sadcaper »

While that article is a great reference point, it still doesn't give us "lazy and inept" users a FAQ or "How To", complete with tools and steps. That's what I'm looking for.

I've contacted a couple people on this board that contributed to this thread asking for the specific tools, but no luck so far. I think if we have a definitive "How To" complete with tools to download more people could enjoy DD 5.1 sound. That's what I need!!!!

Thanks all.
MichaelLAX

Post by MichaelLAX »

sadcaper wrote:While that article is a great reference point, it still doesn't give us "lazy and inept" users a FAQ or "How To", complete with tools and steps. That's what I'm looking for.
Sadly, as of today's date, it just doesn't exist. There is no way to decode AAC 5.1 on an unhacked Apple TV. The closest you can come is to feed its output into a Dolby Pro Logic II decoder.

The Griffin Firewave requires a Firewire port, which just does not exist on an Apple TV and Giffrin recently responded to my inquiry that they have no plans for a USB version... So until hardware comes out that will decode AAC 5.1:

Hopefully soon, we will be looking back at this period of time as a footnote in the evolution of the Apple TV as a home media lounge.
sadcaper
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Post by sadcaper »

While that is true regarding AAC 5.1, there is a method for "tricking" the ATV into using an AC3 file. It involves a lot of formatting and muxing/demuxing, but it's doable. That's why if we had a nice FAQ on the subject, more people would take advantage of it.

Some of the tools needed are Windows based, and I just cannot find them on the net. If the people that are already using these tools would help us get started, then that would make this even more painless.

Thanks!
MichaelLAX

Post by MichaelLAX »

sadcaper wrote:While that is true regarding AAC 5.1, there is a method for "tricking" the ATV into using an AC3 file. It involves a lot of formatting and muxing/demuxing, but it's doable. That's why if we had a nice FAQ on the subject, more people would take advantage of it.
A lot of work on each and every file and: "As long as your original mp4 is apple tv compatible, and your receiver can play Dolby Digital CDs, and your ATV is connected to your receiver via optical, it will work" and he further notes: "Hopefully your audio will be in sync."

If you're going to that effort, why not just add Perian to your Apple TV and output true AC3?
sadcaper
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Post by sadcaper »

Welll, I just don't want to hack my Atv just like I don't want to hack my iPhone. I'd rather use a method that doesn't require hacking, and we have one, its just not fully documented and laid out nicely for us noobs. That's where I as hoping some ppl from this thread would step up and contribute for the rest of us. Hopefully someone will.
gbooker
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Post by gbooker »

sadcaper wrote:Welll, I just don't want to hack my Atv just like I don't want to hack my iPhone. I'd rather use a method that doesn't require hacking
Honestly, you are doing something that Apple never intended for you to ever do. Hacking is pretty much an necessity, in such situations. If you are unwilling to hack you ATV, then you really should be prepared to not have it do anything that the manufacture didn't specify on the box.
sadcaper wrote:and we have one, its just not fully documented and laid out nicely for us noobs. That's where I as hoping some ppl from this thread would step up and contribute for the rest of us. Hopefully someone will.
Yes, there is a method, but its complexity is rather high. The ATV ships with its audio output at 44.1KHz, but nearly every AC3 audio track is 48KHz. This is fine for decoded audio, but for any kind of passthrough, it is nothing short of disaster. So, the method without hacking is thus:
  • Decode the AC3 audio into 6 discrete channels.
  • Resample the audio at 44.1KHz.
  • Encode the audio into 5.1 AC3 at the new sample rate
  • Encapsulate the audio inside a dd-wav
  • Encode the dd-wav using Apple's lossless
  • Stick the Apple lossless track in your mp4
I don't know about you, but I am willing to bet that a vast majority of noobs don't have an AC3 encoder lying around. Now if the ATV was set to 48KHz output, this process is much simpler.

Final word: If you want AC3 passthrough, just hack your ATV. It is a tremendous amount of pain and anguish otherwise.
BucksSaddler
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Post by BucksSaddler »

sadcaper wrote: Some of the tools needed are Windows based, and I just cannot find them on the net.
I think this is the site you are looking for. It details all the programs required (you will also find this link on page 12 of this thread :wink: )

http://web.mac.com/ragboy/iWeb/TheGarci ... 6FE4E.html

I did start using this method and it works fine, but it is a long a winding road (including things like resampling to 44.1KHz).
I've now gone down the route of Perian on my aTV - so much simpler on the endoing side and AC3 Passthru
doctorSpoc
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Post by doctorSpoc »

Berylium wrote:...however, you are comfortable with the 5.0, non-discreet surround provided by Dolby Pro Logic II then you are already good to go...
Berylium, why do you refer to Dolby ProLogic II as 5.0 when it IS actually 5.1? i have used the 5.1 -> DPL II conversion in Handbrake and can confirm from 1st hand experience that it is indeed 5.1 i.e. the sub is indeed being fed low frequency effects as spec'd

http://en.wikipedia.org/wiki/Dolby_Pro_Logic
Wikipedia wrote: Dolby Pro Logic II

In 2000, Dolby introduced Dolby Pro Logic II (DPL II), an improved implementation of Dolby Pro Logic. DPL II processes any high quality stereo signal source into "5.1"—five separate full frequency channels (left, center, right, left surround and right surround) plus one low-frequency-effects (deep bass) channel. Dolby Pro Logic II also decodes 5.1 channels from stereo signals encoded in traditional four-channel Dolby Surround. DPL II implements greatly enhanced steering compared to DPL, and as a result, offers an exceptionally stable sound field that simulates 5.1 channel surround sound to a much more accurate degree than the original Pro Logic.

Because of the limited nature of the original DPL, many consumer electronics manufactures introduced their own processing circuitry, such as the "Jazz", "Hall", and "Stadium" modes found on most common home audio receivers. DPL II forgoes this type of processing and replaces it with simple servo (negative feedback) circuits used to derive five channels. In addition to five full range playback channels, Pro Logic II introduced a Music mode which would not add any processing to the left and right channels, but will still extract a center channel and two surround channels, providing a net effect of a wider center channel.

The Pro Logic II system also features a mode designed specifically for video gaming, and it is frequently used in game titles for Sony's PlayStation 2, Nintendo's GameCube and just recently the Wii as an alternative to digital technologies like Dolby Digital, LPCM or DTS.
jbrjake
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Post by jbrjake »

doctorSpoc wrote:Berylium, why do you refer to Dolby ProLogic II as 5.0 when it IS actually 5.1?
Because it isn't?
i have used the 5.1 -> DPL II conversion in Handbrake and can confirm from 1st hand experience that it is indeed 5.1 i.e. the sub is indeed being fed low frequency effects as spec'd
Well that's pretty funny, since HB doesn't include the LFE track. Dolby tells you not to, because there's no way to differentiate between sources that spread LFE signals between channels and those that truly use the LFE, and if you try to do 5.1 with the former kind, you get nasty interference from the wrong phasing.
doctorSpoc
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Post by doctorSpoc »

jbrjake wrote:
doctorSpoc wrote:Berylium, why do you refer to Dolby ProLogic II as 5.0 when it IS actually 5.1?
Because it isn't?
i have used the 5.1 -> DPL II conversion in Handbrake and can confirm from 1st hand experience that it is indeed 5.1 i.e. the sub is indeed being fed low frequency effects as spec'd
Well that's pretty funny, since HB doesn't include the LFE track. Dolby tells you not to, because there's no way to differentiate between sources that spread LFE signals between channels and those that truly use the LFE, and if you try to do 5.1 with the former kind, you get nasty interference from the wrong phasing.
you actually contradict yourself when you say it isn't 5.1 and then in your second response say... well it is but Dolby says not to implement it as spec'd... so what you really mean is that you guys don't do 5.1 for technical reasons... but DPL II is in fact 5.1.

i have to check my set up... can't remember, but i may have it for the sub to use its crossover the extract the low frequency from the lt and rt channels... was testing it, so don't know which state i left it in.
doctorSpoc
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Post by doctorSpoc »

i've seen responses that there are hardly any, almost none etc, etc receivers that can make use of AAC 5.1... but is there even one? does anyone know of a receiver that actually can make use of AAC 5.1?
realityking
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Post by realityking »

doctorSpoc:

what happens at your setup is that the receiver routes all frequencies under a certain threshold to the subwoofer.
MichaelLAX

Post by MichaelLAX »

doctorSpoc wrote:i've seen responses that there are hardly any, almost none etc, etc receivers that can make use of AAC 5.1... but is there even one? does anyone know of a receiver that actually can make use of AAC 5.1?
The Griffin Technologies FireWave will extract the 6 discrete channels and feed them in six feeds to an amplifier. Any amplifier/home theater that is set up for SACD/DVD-Audio will generally have 6 discrete audio inputs.

The problem is that it needs a FireWire port and, of course, the Apple TV does not have one, and Griffin has told me that have no plans to release a USB version. Of course, a Mac mini or other model would play the AAC 5.1 thru the FireWave. Maybe the Apple TV 2.0 will have a FireWire port...
jbrjake
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Post by jbrjake »

doctorSpoc wrote:you actually contradict yourself when you say it isn't 5.1 and then in your second response say... well it is but Dolby says not to implement it as spec'd... so what you really mean is that you guys don't do 5.1 for technical reasons... but DPL II is in fact 5.1.
I'm sorry, I made the mistake of assuming you had read the post you were responding to, and perhaps the thread you were posting in.

See, Berylium was talking about 5.0 sound because you were reading the beginning of a long tutorial post on how to get surround sound to an AppleTV *using HandBrake*. Later on in the same post you replied to, Berylium expounded:
3. Get non-discreet, 5 channel audio through HandBrake and Dolby Pro Logic II

This method is far and away the easiest. Open your DVD with HandBrake, select the HB-AppleTV Preset, and click Start. Again, I glossed over potentially important stuff like checking for deinterlacing, changing audio bitrate, different x264 options, etc. but those are all things you’d need to fool with in the other options as well. The result is a movie, like the movie from option 2, that works with both the AppleTV and iTunes interfaces. You get all your movie art, descriptions, etc. and you can play the movie from your AppleTV connected to any device, not just a receiver, since the audio track is just a specially encoded stereo track. Your Dolby Pro Logic II capable receiver, however, will be able to pull out 5 channels of sound from that stereo signal. You get center, left, right, left-rear, and right-rear channels of audio but you lose your LFE (subwoofer) channel.
So I'm not seeing how I'm contradicting myself, in a discussion of downmixing to DPL2 *using HandBrake* to say it isn't 5.1. I mean, I could only assume you were discussing HandBrake too -- you were replying to a post about using HandBrake (which was in response to another HandBrake user asking for help), in the HandBrake forum, and the very next sentence you wrote was about using DPL2 in HandBrake and how, you claimed, it was 5.1.

Definitive statement that HandBrake does not downmix the .1 from 5.1 tracks:
http://handbrake.m0k.org/irclogs/handbr ... 1_pg5.html (see the whole log for great technical detail of the whys and why nots)
[23:01] [maurj] rhester: the current dpl2 downmix I've patched into liba52 is just dropping the LFE channel
[23:01] [maurj] rather than spreading it out
[23:02] [maurj] so it's effectively a 5.0 matrix-encoded mix
doctorSpoc
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Post by doctorSpoc »

realityking wrote:doctorSpoc:

what happens at your setup is that the receiver routes all frequencies under a certain threshold to the subwoofer.
ok, so even if i don't have my system set up to use the sub's crossover, the sub will still be getting fed, it's just that the low frequency info is extracted from the other channels not from a .1 channel? so in that case the mix might not be exactly the same as DD or DTS? because i did notice that... but it's still pretty damn good imho.
dynaflash
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Post by dynaflash »

doctorSpoc wrote:but it's still pretty damn good imho.
Yes, yes it is. maurj did a fantastic job with HB's audio.
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