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ATV1 - 24/96 - am I losing it?


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As far as I was aware, the Apple TV 1st generation is only capable of outputting 48khz from it's optical port. I am sitting here listening to Aretha Franklin's "Spirit In The Dark" (HD Tracks, FLAC) via XBMC and my a/v receiver (Marantz SR5500) is registering 96khz. The amp categorically isn't intentionally lying to me, telling me what I want to hear, it is correctly reporting the sampling rate on each piece of music I throw at it (although it remains totally silent on all pieces above 96khz, which is exactly what it says on the tin).

 

Everything I have read on this says that the ATV1 always downsamples to 48khz. Did I miss something somewhere, is there I thread on this I can't find or it is common knowledge and I am having a Saturday morning brain-phart?

 

If I use my Squeezebox (SB3), the same piece of music is downsampled to 48khz, which is precisely what one would expect. The only logical conclusion is that XBMC is somehow "upgrading" the digital output on the ATV1.

 

...not that I am complaining, it was just unexpected.

"The greatest deception men suffer is from their own opinions"

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I think the ATV is only sending 16 bit data, I am trying to work out (digging into the serial protocol) what my amp is seeing. Nevertheless it sounds excellent and given the very budget nature of the kit (I think I paid £150 or so on eBay for the receiver, ATV1s are cheap and XBMC free) this is a very viable entry level audiophile setup.

"The greatest deception men suffer is from their own opinions"

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Jailbroken ATVs while using XBMC don't use Airplay/AirTunes so it becomes hardware limited to resolution. The 44/48 limit is a protocol/software limitation. Shame Apple didn't consider audiophiles in this decision. I'd expect a change down the pike as HD streaming g services are growing leaps and bounds with hi bitrate PCM multichannel. That being said, HiRes will probobly be limited to the HDMI output.

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I've tried, and failed, to do this with ATV2, so I think there is some hardware limitation, at least in the case of ATV2.

 

ATV2 also presents an audio setting allowing you to choose between "16 bit" and "automatic", suggesting that something other than 16 bit is possible as well.

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After some investigation , as reported by my AVR, it seems that the ATV1 was also processing 24bits using XBMC. I hsve an ATV2 but am only using it for video, not audio, so can't say what XBMC is doing on there.

 

To be clear I am using an ATV1 with Openelec, not running XBMC from Frontrow connecting via toslink to my AVR. Not sure if that makes a difference compared to hacked Frontrow.

 

It would seem an odd decision for Apple to choose to output hi-def music over HDMI only. That said I will test the ATV1 using HDMI and see what happens. According to the AVR documentation it accepts up to 192khz; wouldn't it be interesting if an ATV1/Openelec/XBMC proved capable of 24/192....

 

I've tried, and failed, to do this with ATV2, so I think there is some hardware limitation, at least in the case of ATV2.

 

ATV2 also presents an audio setting allowing you to choose between "16 bit" and "automatic", suggesting that something other than 16 bit is possible as well.

"The greatest deception men suffer is from their own opinions"

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I think the hacked frontrow (at least the one I have somewhere) just launches XBMC and exits Front Row. I will have to google Openelec. Nice pups. Are they goldens?

 

OK, I see that Openelec is linux. The jailbreak for ATV2 is iOS-based BSD, so that might also be a limitation.

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It's getting pinker as she gets older. She was about 9 months in that photo. Waiting for someone to tell us to take this discussion elsewhere!

"The greatest deception men suffer is from their own opinions"

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Finally worked up the courage to click on it....and there was me thinking you were probably being ironic.

 

Don't start me on sad dog stories.

"The greatest deception men suffer is from their own opinions"

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After some investigation , as reported by my AVR, it seems that the ATV1 was also processing 24bits using XBMC. I hsve an ATV2 but am only using it for video, not audio, so can't say what XBMC is doing on there.

 

To be clear I am using an ATV1 with Openelec, not running XBMC from Frontrow connecting via toslink to my AVR. Not sure if that makes a difference compared to hacked Frontrow.

 

It would seem an odd decision for Apple to choose to output hi-def music over HDMI only. That said I will test the ATV1 using HDMI and see what happens. According to the AVR documentation it accepts up to 192khz; wouldn't it be interesting if an ATV1/Openelec/XBMC proved capable of 24/192....

 

I have an ATV1 as well and I know that the hardware limitation is 24/96 via Toslink. The ATV software it comes with limits the output to 16/44.1 but I installed OSX which allowed 24/96. I am now experimenting with Openelec 3 which I think is what you are using to get 24/96. I think previous versions of Openelec included an XBMC version that downsampled material so your discovery probably coincides with recently upgrading to OE 3?

 

I think that you could run ATV1 with Openelec and a USB Dac that supports 24/192 although I have not tried that myself and it might be difficult to install drivers for that dac if needed.

 

From reading I think ATV2 is hardware limited to 16/48.

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Good theory but actually no, I was seeing this before upgrading to 3.0. It was only two weeks ago (before I upgraded) that I had my "hang on a minute" moment (minute) and realised the ATV1 "shouldn't" be behaving in this way.

 

You seem to know a lot more about this than I do (admittedly that's not difficult...) but I assumed it was the new AudioEngine in Xbmc 12 that was the culprit and not Openelec. Openelec is starting to annoy me a littler, not least it's inability to play the MLB.com plugin, so I was going to try XBMCBuntu. I will report should the audio output behave differently.

 

Marc

"The greatest deception men suffer is from their own opinions"

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Good theory but actually no, I was seeing this before upgrading to 3.0. It was only two weeks ago (before I upgraded) that I had my "hang on a minute" moment (minute) and realised the ATV1 "shouldn't" be behaving in this way.

 

You seem to know a lot more about this than I do (admittedly that's not difficult...) but I assumed it was the new AudioEngine in Xbmc 12 that was the culprit and not Openelec. Openelec is starting to annoy me a littler, not least it's inability to play the MLB.com plugin, so I was going to try XBMCBuntu. I will report should the audio output behave differently.

 

Marc

 

You are right that the new AudioEngine is only available in XBMC 12. I had thought versions of Openelec prior to 3.0 were using XBMC 11, but I'm not actually sure about that. I don't think you can use xbmcbuntu on Apple TV 1 but you can use Crystalbuntu, which I have tried out. Crystalbuntu has not yet incorporated XBMC 12 though, which is why I switched to Openelec. I noticed that OE uses more memory than Crystalbuntu but basically they are pretty similar.

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  • 5 months later...

Hi Guys,

 

I stumbled across this thread while searching for a method of establishing an audiophile quality network using ATV. By chance I recently purchased an ATV Gen 1 with XBMC installed.

 

I am very excited by the prospect of streaming 24/96 and like everyone else frustrated by ATV resampling to 16/48. I have little tech knowledge and I would like to confirm my understanding from your thread that the ATV Gen 1 with XBMC installed can output 24/96 via the optical out to my DAC. If this assumption is correct my questions are:

 

1. Can ATV with XMBC installed output bit perfect i.e. CD quality files such as 16/44.1 streamed to it without resampling via

 

a. ethernet

b. airplay

 

2. Can ATV with XMBC installed output bit perfect from its own hard drive without resampling .. my model is 160G.

 

3. Can the ATV with XMBC installed output 24/96

 

a. wirelessly via airplay?

b. from its own hard drive?

 

4. What are the steps I need to follow to do this. (I already know how to connect the ATV to my network.)

 

5. What is openelec and if it is software do I need to install it onto the ATV or is it already installed as part of XBMC.

 

Thanks very much in in advance.

 

Ajax

LOUNGE: Mac Mini - Audirvana - Devialet 200 - ATOHM GT1 Speakers

OFFICE : Mac Mini - Audirvana - Benchmark DAC1HDR - ADAM A7 Active Monitors

TRAVEL : MacBook Air - Dragonfly V1.2 DAC - Sennheiser HD 650

BEACH : iPhone 6 - HRT iStreamer DAC - Akimate Micro + powered speakers

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I think the answer to all your questions is "Yes" but there was some debate here over whether or not XBMC messes with the output and is truly bitperfect. XBMC does have Airplay built in.

 

ATV1 is hardware capable of outputting 24/96 bitperfect as I have done this with Squeezelite. I think it is the XBMC software that might not be ideal for audio yet.

 

For #5: Openelec is a linux distribution that has XBMC preloaded and has been preconfigured to work on ATV1. You have to install it instead of the apple software.

 

Installing OpenELEC on AppleTV - OpenELEC

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Hardware limit is 24/192 through optical , but it doesnt support 24/88 and 24/176 if I recall correctly. But you could use an USB/Spdif adapter. (Supports USB Audio Class 2.0 through Linux)

 

Hardware limit is 24/96 but you could go beyond with USB.

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Hi Ibastian and Bloodwound,

 

Thanks very much for your feedback - I am more than happy with 24/96 as that is the max I have previously downloaded to match my Benchmark DAC1 HDR USB input resolution.

 

I will download OpenELEC using Ibastian's link.

 

Thanks very much for your help and replying to my questions - much appreciated.

 

Ajax

LOUNGE: Mac Mini - Audirvana - Devialet 200 - ATOHM GT1 Speakers

OFFICE : Mac Mini - Audirvana - Benchmark DAC1HDR - ADAM A7 Active Monitors

TRAVEL : MacBook Air - Dragonfly V1.2 DAC - Sennheiser HD 650

BEACH : iPhone 6 - HRT iStreamer DAC - Akimate Micro + powered speakers

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Hardware limit is 24/96 but you could go beyond with USB.

 

Not to beat a dying horse, but I'm positive that the hardware limit is 192. Squeezelite works at 192khz but needs LMS 7.8 (nightly) to work properly beyond 96khz.

To verify you can type:

cat /proc/asound/cardx/stream0 (where x is a number, probably 0 or 1)

Yay!

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I have an ATV1 as well and I know that the hardware limitation is 24/96 via Toslink. The ATV software it comes with limits the output to 16/44.1 but I installed OSX which allowed 24/96. I am now experimenting with Openelec 3 which I think is what you are using to get 24/96. I think previous versions of Openelec included an XBMC version that downsampled material so your discovery probably coincides with recently upgrading to OE 3?

 

I think that you could run ATV1 with Openelec and a USB Dac that supports 24/192 although I have not tried that myself and it might be difficult to install drivers for that dac if needed.

 

From reading I think ATV2 is hardware limited to 16/48.

 

ATV1 is not limited to 16/44.1 but 48. However, what's important is the fact of not upsampelling to 16/48 as ATV2 does. Therfore, we can count on bit perfect 16/44.1 if such streamed!

I am very interested in how have you updated ATV1 OSX?

I wish to pudate original OSX to 10.6 in order to install audirvana on ATV1. It could be a sollution for your question as well since audirvana is capable of streaming HD.

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It goes up to 24/192:

 

Proof:

# cat /proc/asound/card0/codec#0

Codec: Realtek ALC889A

Address: 0

AFG Function Id: 0x1 (unsol 1)

Vendor Id: 0x10ec0885

Subsystem Id: 0x106b2800

Revision Id: 0x100103

No Modem Function Group found

Default PCM:

rates [0x560]: 44100 48000 96000 192000

bits [0xe]: 16 20 24

formats [0x1]: PCM

Yay!

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  • 1 year later...

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