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iPod / iPhone output digital audio via Apple Camera Connector for iPod? - Page 5

post #61 of 78
Quote:
Originally Posted by DanBa View Post

 


New iPhone 4S & new iOS 5.0 compliant to the Camera Connection Kit?

 



Anyone? I might be able to test this out on Friday. I'll post here...

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post #62 of 78

Doesn't work.

 

Accessory not supported.

 

Oh well, it was worth a try.

post #63 of 78
Thread Starter 

Thanks!

post #64 of 78

Hi,

 

I'm not sure if this is the right place to ask, but did anyone try streaming music from their iDevice to the apple TV using Airplay?

 

I did and i find the SQ is inferior when streaming from my iPod's music player to the apple TV in comparison to streaming iTunes from my mac computer to the apple TV and i wonder why.

 

In both cases I am using the same .wav files and the apple TV optical out is connected to my DAC. I assumed the bitstream (1s & 0s) would be identical/bit perfect in both scenarios but it doesn't appear to be the case...are all bitstreams not created equal?

 

Thanks in advance for any input/explanation.

 

Note: All playback settings in iTunes such as crossfade, equalizer, etc. are disabled.

post #65 of 78

even bit-identical audio data signals can "sound different" after d/a conversion if jitter affects the quality of the d/a conversion process. Different cables, lengths, and transmission protocols can affect jitter issues differently, which in turn can affect d/a conversion. Jitter doesn't affect bit accuracy, but it affects *when* each digital sample is converted to analog voltage... which affects how your ears perceive the resulting waveform.

post #66 of 78
Thread Starter 

As far as I understand, in case of AirPlay, the audio player is in the Apple TV, and the jittered PCM stream is created by the player.

post #67 of 78

daVID Boulet,

 

Thanks for responding and sharing your thoughts. In my case both data streams (iTunes from mac & iPod music player) are transmitted wirelessly to the Apple TV device with a common optical cable between the ATV & DAC. Therefore, the "net" A/B comparison is between the two bitstreams. Thanks for reminding me about jitter, i guess that is what is responsible for the differences i hear. I suppose it makes sense that a portable device such as an iPod would have higher jitter rates...

 

DanBa - Thanks you as well for your thoughts on jitter, that is most likely the reason for the audible difference.

 

Thanks guys!

post #68 of 78
Thread Starter 

 

As far as I understand, the audio jitter is not involved in your AirPlay cases.

 

From the Mac/iPod to the DAC of the Apple TV, there are two different streams:

. computer networking stream: from the Mac/iPod to the audio player of the Apple TV

. digital audio stream or PCM stream: from the audio player of the Apple TV to the DAC of the Apple TV.

The audio jitter which affects the D/A conversion is only involved in the PCM stream.

Audio jitter is an attribute of PCM digital signals, particularly clocks that impart the timing to the data that is being moved from the player to the DAC.

 

In the AirPlay iPod case, I think there are some computer networking losses (iPod CPU not able to fill the sending buffer just in time ?, not well-formed iPod transmission waveforms ?, mismatching of iPod sending buffer size and Apple TV reception buffer size ? …)

 

"Streaming is a method of delivering data to a device in a piecemeal manner. Rather than retrieving the whole file, the renderer fetches only a small portion of the file then starts playing immediately. Within the DS (or Apple TV) is a small reservoir, or buffer, containing the next few pieces of the file, in a queue ready to be played. The buffer is kept topped up, while audio is playing, by retrieving more data from the network. The buffer allows the audio to continue uninterrupted in the event of any brief dropouts in the network delivery. It also allows the audio to be faded out slowly in the event of any long term network interruption."

http://docs.linn.co.uk/wiki/index.php/Introduction_To_DS_Concepts

post #69 of 78
Quote:
Originally Posted by drummerboy47 View Post

Doesn't work.

 

Accessory not supported.

 

Oh well, it was worth a try.


It won't ever work.  The accessory exists only because the iPad didn't have a camera and the phone did.  For this reason, Apple probably will never support the phone.

post #70 of 78
Thread Starter 

 

"I installed iOS5 beta 3 on my iPhone 4 and FINALLY I can plug the USB Camera Connection Kit with no "Unsupported Device" message, and it works great with any USB in/out audio device (power limitations seem to be similar to the iPads). 
This is a whole new world for mobile recording. I hope USB audio stays enabled in the final iOS5 release."
 
 
"UPDATE: this feature has been disabled in iOS 5.0 beta since beta 7, including the final released version.
CCK-compatibility for anything else than iPad has been deliberately disabled by Apple."
 
 
Connecting USB MIDI Keyboard to iPhone 4 (iOS5 beta 3) via iPad camera connection kit: 
post #71 of 78
Thread Starter 

iPhone & new iOS 5.1 compliant to the Camera Connection Kit?


Edited by DanBa - 3/7/12 at 1:14pm
post #72 of 78

subscribed.

post #73 of 78

Nope mad.gif
 

Quote:
Originally Posted by DanBa View Post

iPhone & new iOS 5.1 compliant to the Camera Connection Kit?



 

 

post #74 of 78

I think we need a device that says the following:

 

Device:  Let me in and at the music data

iPad:  No way.  You have not yet anted up and made Apple even richer.

Device:  Suit yourself.  I will now go to connect with an Android device whose music files are up for the taking.

 

That's the dialogue I am looking forward to.

post #75 of 78
Thread Starter 
Quote:
Originally Posted by pekingduck View Post

Nope mad.gif
 



 

 



Thanks!

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