Does the DD indicator illuminate on your receiver when you play the movies? My Onkyo has DD, DTS, Neo and PLII indicators - that's how I know the files are being passthrough'd to the receiver. If your DD illuminates, you'd know for certain.
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Apple TV and Surround Sound
- Thread starter Cave Man
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Does the DD indicator illuminate on your receiver when you play the movies? My Onkyo has DD, DTS, Neo and PLII indicators - that's how I know the files are being passthrough'd to the receiver. If your DD illuminates, you'd know for certain.
Sadly I am have not downloaded any of the movies. The HD ones are 480 points which is around 5 dollars. MS claims the files to have 5.1 Digital Audio. I would be inclined to think it is DD, but it is hard to say cause the 360 can encode DD or DTS.
Hmm, I wonder, then if it's some other format. Does the Xbox 360 have its own amplifier? If so, then this makes sense. If it doesn't that would imply that it is decoding the 6 discrete channels that would need to be sent to a receiver/amp that has 6 inputs for these channels. Time for Google...
OK, here it is:
http://www.dolby.com/consumer/games/yourconsole.html
Looks like the Xbox takes a Toslink cable to a receiver to get Dolby Digital 5.1. So, it should work so long as the video is encoded with DD. It'd be nice if you could somehow determine that. Sounds like 5 or 6 gigs may be a realistic expectation after all (fingers crossed).
FOX movies
Well, it looks like there will be some movie activity at MacWorld, provided the rumor is correct. Let's hope Apple introduces DD or DTS passthrough to Quicktime, both for Macs and Apple TV. Add a little HD video and all would be good...
Well, it looks like there will be some movie activity at MacWorld, provided the rumor is correct. Let's hope Apple introduces DD or DTS passthrough to Quicktime, both for Macs and Apple TV. Add a little HD video and all would be good...
One step closer?
I've done a bit more digging and there is a way to get Front Row on a Mac to do Dolby Digital AC-3 5.1 surround passthrough, at least with Leopard. It requires that you do the following:
1. Use Handbrake to encode your DVD as an AVI (MPEG-4 with AC-3 passthrough) file. You then open the file with QuickTime Pro and then save as a self-contained movie. This movie can then be dropped into iTunes, making it available to the Mac through Front Row. However, it does not show up on the ATV since it is an incompatible file type (even though it's a QuickTime movie). I did this with the first Spiderman movie and it was compressed at 2500 bit rate with AC-3 5.1 DD to a final size of 2.5 gb.
2. Follow the directions here to install Perian, configure Audio Midi Setup to digital output, then a modification of the com.cod3r.a52codec.plist file using Property List Editor (part of Apple's development package and a free download).
Once these are done, both QuickTime stand-alone and Front Row (through QuickTime) play the movie file with Dolby Digital 5.1 passthrough to a receiver via the optical port (of course, the receiver must be able to decode Dolby Digital). Installation of Perian and the com.cod3r.a52codec.plist file on an ATV's hard drive would be simple enough (just by pulling the hard drive and connecting it to an Intel-based Mac using USB, or by AFP if the hack is in place). But would Perian allow the movie file to show up on the Apple TV?
Also, the Audio Midi change is something I have no idea about. When I set these settings on my Mini, ~Library/Preferences/com.apple.audio.SystemSettings.plist was the only file that I can readily see was modified (by sorting files by date modified). I do not know if there are invisible files that might have also been modified. It may be that this file could be copied straight over to the ATV hard drive as well, thus completing the activation of AC-3 Dolby Digital passthrough on the Apple TV. I won't be exploring this further until after Tuesday's show, but thought I'd share this info (which may already be known by others). If you have Perian installed on your ATV and have AFP access, it might be worth a try to see if it works.
I've done a bit more digging and there is a way to get Front Row on a Mac to do Dolby Digital AC-3 5.1 surround passthrough, at least with Leopard. It requires that you do the following:
1. Use Handbrake to encode your DVD as an AVI (MPEG-4 with AC-3 passthrough) file. You then open the file with QuickTime Pro and then save as a self-contained movie. This movie can then be dropped into iTunes, making it available to the Mac through Front Row. However, it does not show up on the ATV since it is an incompatible file type (even though it's a QuickTime movie). I did this with the first Spiderman movie and it was compressed at 2500 bit rate with AC-3 5.1 DD to a final size of 2.5 gb.
2. Follow the directions here to install Perian, configure Audio Midi Setup to digital output, then a modification of the com.cod3r.a52codec.plist file using Property List Editor (part of Apple's development package and a free download).
Once these are done, both QuickTime stand-alone and Front Row (through QuickTime) play the movie file with Dolby Digital 5.1 passthrough to a receiver via the optical port (of course, the receiver must be able to decode Dolby Digital). Installation of Perian and the com.cod3r.a52codec.plist file on an ATV's hard drive would be simple enough (just by pulling the hard drive and connecting it to an Intel-based Mac using USB, or by AFP if the hack is in place). But would Perian allow the movie file to show up on the Apple TV?
Also, the Audio Midi change is something I have no idea about. When I set these settings on my Mini, ~Library/Preferences/com.apple.audio.SystemSettings.plist was the only file that I can readily see was modified (by sorting files by date modified). I do not know if there are invisible files that might have also been modified. It may be that this file could be copied straight over to the ATV hard drive as well, thus completing the activation of AC-3 Dolby Digital passthrough on the Apple TV. I won't be exploring this further until after Tuesday's show, but thought I'd share this info (which may already be known by others). If you have Perian installed on your ATV and have AFP access, it might be worth a try to see if it works.
So, long story short, it looks like this problem is now solved based on today's annoucnements. Am I jumping to conclusions? Understand that it's only DD, and not DTS, etc.
At least a step in the right direction. It looks like only HD rental movies will be DD. Not sure why regular DVD's will not be DD since they are on disc. Can anybody confirm this?
Regular DVDs are on disc? I'm not sure what you are saying. There is no disk in the iTunes Rental scheme... (other than your hard drive).
Kevin
Movies on regular DVD's have DD but non HD movies on iTunes don't have a DD soundtrack. At least that's how I read it.
Right, but my point was that if you use 5.1 through various programs, the ATV will now be able to output, whereas before it could not!
It looks like the ATV will do 5.1 output with media encoded in Dolby Digital. The caveat will be whether the ATV will accept all media that can be encoded in Dolby Digital.
Quicktime chatters with AC-3
The Quicktime update now plays the AC-3 chatter over the speakers, from both .mov and .avi files. I think before it would only play back the video and give an error about an unsupported type (presumably, the audio). Can someone confirm that QT 7.4 will now passthrough AC-3 audio to their receiver by optical cable for 5.1 surround sound playback? If so, does it work with both .avi and .mov files? (I've not updated my home theater Mac Mini yet until I'm sure nothing will be broken. Otherwise, I would do this test myself.)
The Quicktime update now plays the AC-3 chatter over the speakers, from both .mov and .avi files. I think before it would only play back the video and give an error about an unsupported type (presumably, the audio). Can someone confirm that QT 7.4 will now passthrough AC-3 audio to their receiver by optical cable for 5.1 surround sound playback? If so, does it work with both .avi and .mov files? (I've not updated my home theater Mac Mini yet until I'm sure nothing will be broken. Otherwise, I would do this test myself.)
I hate posting similiar question in two places, but did not see this thread on the ATV surround sound.
https://forums.macrumors.com/threads/415346/
I define HD content = HD video + HD audio, plain and simple.
For "true" HD content Apple should at least use one of the higher quality surround sound formats, like the HD lossy formats DD+ or DTS HD High Resolution audio.
I'm guessing the lossless Dolby TrueHD/DTS-HD Master Audio takes up too much bandwidth.
I will NOT forgo HD audio, true Home Theatre/Cinema experience includes both HD video AND HD audio, DD 5.1 while good should not be the std for Apple TV HD downloads.
More and more receivers have the DD+ capability, you can really hear the difference over DD 5.1.
https://forums.macrumors.com/threads/415346/
I define HD content = HD video + HD audio, plain and simple.
For "true" HD content Apple should at least use one of the higher quality surround sound formats, like the HD lossy formats DD+ or DTS HD High Resolution audio.
I'm guessing the lossless Dolby TrueHD/DTS-HD Master Audio takes up too much bandwidth.
I will NOT forgo HD audio, true Home Theatre/Cinema experience includes both HD video AND HD audio, DD 5.1 while good should not be the std for Apple TV HD downloads.
More and more receivers have the DD+ capability, you can really hear the difference over DD 5.1.
Then according to your definition, ATV does not support "HD content", nor can you get it from the iTunes Store.
However, I think that most people are going to be very happy with Apple's HD rentals. 720p and 5.1 are a big step up.
Kevin
I'd be curious why they can't go DD+ for "true HD", is it a technical issue?
(need new decoder chip in ATV) Bandwidth issue? (too large file size)?
Political issue? (studios don't want people to have DD+ for fear of copy/dist)
Dolby Digital Plus or Dolby TrueHD is as much a technical issue as it is an investment issue.
The vast majority of people do not have Dolby TrueHD or Dolby Digital Plus decoding hardware. But the adoption rate of Dolby Digital AC-3 5.1-channel surround has grown considerably.
Dolby Digital Plus is really a theatrical application, IMO... where an auditorium of large scale is going to take advantage of the additional channels and fidelity. Dolby TrueHD is a consequence of greater storage but, realistically, I don't think that the average viewer will know the difference.
Hell, half the people who insist on Dolby Digital fail to realize that it in and of itself is a highly compressed format (448Kbps for 5.1 on DVD, and 320Kbps for 5.1 theatrical)... but this is because, as a perceptual coding schema, it is acoustically transparent to the uncompressed source by and large... .especially true in the home application where metadata parameters further squeeze greater performance out of the dynamic range of Dolby Digital.
I do believe that, also, a different chipset is required than the one in the AppleTV.
I think a better solution would be Dolby Digital Live, whereby multichannel sources could be transcoded on the fly to AC-3, but AC-3 passthrough is equally sufficient when all the source content has an AC-3 passthrough track embedded in the file... and since 1992 Dolby Digital has withstood the test of time despite all that the uneducated audiophile (read: layman listeners with no real engineering background) has to say about it.
Movies on regular DVD's have DD but non HD movies on iTunes don't have a DD soundtrack. At least that's how I read it.
This is correct, for now. It could change. I'm not quite sure what the issue is... could be technical, could be negotiations-related, could be product differentiation so they can sell more HD rentals.
Actually, now that I think about it... here's your answer... The iPods and iPhone may not have the hardware/software to decode Dolby Digital AC-3 bitstreams or the bitstream is too large. It doesn't matter if the software can "unpack" the passthrough AC-3 from the H.264 file... you've still got two problems:
a) iPod/iPhone does not have a hardware/software AC-3 decoder, and such software would require a license in every instance making iPods and iPhones more expensive than they are now.
b) The bigger problem is that the audio chipset in the iPods and iPhone appear to be designed to process 320Kbps AAC at most. 5.1 AC-3 however, is 448Kbps from a DVD.
This makes it complicated, and unnecessarily so, for one standard definition file to be entirely mobile... for now.
Again, future iterations could change this, but you're also going to run into greater storage requirements, greater licensing requirements, greater processing requirements, etc. raising the cost on it. Be prepared for that.
Frankly, I don't see that as nearly as big a deal since... if you don't have an AppleTV, Dolby Digital isn't going to be of as much use to you since you won't be carrying a 5.1 surround system with you wherever you go, and if you DO have an AppleTV, you probably have a High Definition TV, and can rent HD rentals instead of the SD ones.
This is all fine but when it comes to renting movies in one of the HD formats both HD and BD use DD HD and DTS HD. So for iTunes to be competitive I would hope they would include the formats sometime in the future as a pass through.
Why? Do you have a DTS-HD processor or a Dolby Digital TrueHD processor?
Do you know anyone who does?
How many of the people who have BluRay or HD DVD have a DTS-HD or Dolby Digital HD processor? Mind you if they have only DTS-ES or Dolby Digital EX it's just going to play the compressed track... not the uncompressed one.
Being competitive is not about having every feature under the sun... it's about having the features that people will actually pay for. Which is often different from what they say they will pay for. This is why Apple is smarter to deploy things in a tiered strategy and use actual sales data, not just marketing survey data, to dictate the direction of their future products. People often say one thing and settle for another. Companies that bank blindly on what people say and not what they do can go bankrupy very, very quickly.
There's a reason Apple has $15 billion in cash and zero debt... and thanks to that, they'll be around to make AND support that revision 2 or 3 or 4 that you are looking for, rather than starting with 4, going bankrupt and then having to close shop rendering your investment worthless. Many a startup has gone out precisely in this manner... perhaps you've heard of a few?
Simply no.
First of all, PLII supports 5.1 channel matrixed sound. You seem to be confusing it with PLI, which only had stereo and a center channel.
Second, encoding to PL2 is *not* just ripping the track as stereo. It involved decoding all 6 channels and applying phasing to the surround channels so they can be merged with the stereo channels.
I can prove it. With math:
http://trac.handbrake.fr/browser/trunk/contrib/patch-a52dec.patch?rev=483
More specifically, for those who are bored/geek enough to take interest... ProLogic II is not technically a format. It is an encoding/decoding algorithm. The format in question is, often, Dolby Surround analog. More recent programs, specifically games, have been encoded in Dolby ProLogic II or IIx specifically... but all movies in an analog Dolby surround format are generally Dolby Surround analog to begin with. Dolby Digital soundtracks contain a Dolby Surround analog matrix embedded in the L-R channels for home systems that are ProLogic I/II only.
In the transcoding process, a Dolby Digital AC-3 5.1-channel bitstream is demultiplexed into five discrete full range channels, and one LFE channel. These are L,C,R,SurL,SurR, and LFE.
While Dolby ProLogic II intelligently places center dialogue and LFE by way of filters, the SurL and SurR channels are stereo matrixed into the front L and R channels by way of shifting their signals 90 degrees out of phase with the L and R.
The ProLogic II decoder samples the audio and extracts the portion of the signal at 90 degrees off axis from phase and sends these to the SurL and SurR channels. If the source was Dolby Surround analog, and only one mono surround channel existed, then the SurL and SurR output will be 2-speaker mono. If the source was Dolby Digital, however, Dolby Surround and Dolby Digital encoding hardware/software matrixes the SurL to the L channel, and the SurR to the R channel.. .so the demuxed output is identical to the 5.1 Dolby Digital surround.
A bandpass filter sends frequencies below 120Hz to the LFE. Another filter removes dialogue by... if I recall correctly, a bandpass filter that covers the range of normal human dialogue, particularly if it's centered in the stereophonic image of the playback.
The LFE is not tricky, because if the source was a Dolby Digital soundtrack to begin with, and this will surprise some audio snobs who insist that LFE crossovers be set to 80Hz... Dolby Digital licensed encoding hardware/software applies a bandpass filter at 120Hz to remove all frequencies below 120Hz from the mains and encode them in the LFE channel only. This is by default, but on occasion engineers can set it manually... THX engineers tend to set the LFE low-pass at 80Hz. This is hard encoded in the mastering stage, not applied by the Dolby Digital processor/decoder. Thus, the processor doesn't have to do any "guessing" as to what to send to the LFE on your 5.1 surround system, the cutoff is in the bitstream of the source. Now, this is assuming the source was a Dolby Digital soundtrack. But if the source was a Dolby Surround analog soundtrack, no LFE channel actually existed and the bandpass is applied across the board... i.e. across all full-range channels, and the results sent to the LFE output.
So what does all this mean... It means that the proper Dolby Digital or ProLogic II decoding hardware can do a very good job of discretely extracting 5.1 channels of surround from a Dolby Surround analog mix.
Granted, it will not always sound identical to a Dolby Digital mix, but that depends on more than just one being digital vs. one being analog. It depends more so on how discrete the channels were to begin with (I've heard some DD mixes worse than some Dolby Surround mixes), the quality of the overall mastering of the source (garbage in, garbage out), the quality of the decoder (and whether or not it is a LICENSED decoder), the quality of the speakers, etc.
Keep in mind that Dolby Digital is also a multiplexed format... there aren't five separate bitstreams in an AC-3 file... but digital demultiplexing (at a low cost factor) can be more discerning because frequencies in each channel are reconstructed from packets of data instead of complex frequencies.
HOWEVER, the quality of analog multiplexing can surpass digital multiplexing... but it depends on the quality of the hardware and software in use. Vinyl doesn't win over CD's, though, because at low cost, digital encoding is more efficient at error-free reproduction -- there digital wins out. Vinyl is a very, very dirt cheap storage and reproduction medium. It takes tremendously expensive technology to surpass digital multiplexing in the analog world... and I don't mean a $20,000 turntable. I mean entirely different technology like Dense Wavelength Division Multiplexing (DWDM) which can combine 80-100 wavelengths of light into one waveform that can transmit more than the per second traffic of the entire internet in 1997.
Avatar74 ;
I respect everything you've said in thhis thread, great points and well thought out.
And yes, Apple is extremely good at matching the "real" consumer needs at price point they will pay vs packing all the "perceived needs" into devices.
With that said, I have just bought the newly released Denon AVR-4308CI for my basement Home Cinema - which has all the lossless HD audio formats, until 2 weeks ago I had "just" DD 5.1/DTS in my 7 year old Onkyo 787, which is still a decent A/V unit.
My right now basement project can be seen here:
https://forums.macrumors.com/posts/4763565/
Does it matter? If I'm paying $4.99 for a HD rental is it reasonable for me to expect that it's the same quality as the HD/BD DVD that I can rent for less??? I'm sure Apple will get the audio formats sorted out eventually.
I have a Denon 3808CI, look up the specs if you want to know.