iTunes 9 has WASAPI (Updated: Zune 4 also has bitperfect out)
Sep 10, 2009 at 4:01 AM Thread Starter Post #1 of 81

lmf22

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iTunes 9 was released today and I just installed it. In the QuickTime audio settings there's an option for Windows Audio Session. Does this mean iTunes finally has WASAPI support?

Open Quicktime. Go to Edit > Preferences > QuickTime Preferences > Audio tab. You can select Windows Audio Session under "Play Audio Using."
The other options are "Safe Mode (waveOut only)" and "Direct Sound."

UPDATE (also updated original post): Zune 4 also has bitperfect output.

I recently got the Zune HD and though I should see whether the Zune 4 software has bitperfect output. It does.

I did the following tests and the receiver detected and played the DTS file:

1) Zune 4 does not seem to support WAV files so I converted it to WMA Lossless with dbPowerAmp. The DTS WMA Lossless file played fine. This also shows that conversion from WAV to WMA Lossless is indeed lossless.

2) Just like iTunes 9, when I played a sound (e.g., a Windows sound effect, YouTube, a movie on KMPlayer, other videos with Firefox) while the DTS file was playing, the DTS signal was lost. But when the other sounds stopped playing, the receiver detected the DTS signal again.

3) I also tried different conversions with dbPowerAmp. All played fine (the received detected and played the DTS signal)
WAV to WMA Lossless (played with Zune 4)
WAV to Apple Lossless (played with iTunes 9)
WAV to FLAC to Apple Lossless (played with iTunes 9)
WAV to FLAC to WMA Lossless (played with Zune 4)

All bitperfect as long as no other audio streams are playing.
 
Sep 10, 2009 at 5:07 AM Post #2 of 81

Ham Sandwich

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Interesting. But even if it does have the option for using Windows Audio Session for output you still need to find out if it us using exclusive mode or shared mode. Exclusive mode is the one that has the potential for bit perfect output.
 
Sep 10, 2009 at 1:37 PM Post #3 of 81

tosehee

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Subscribed
 
Sep 10, 2009 at 1:56 PM Post #4 of 81

azncookiecutter

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Haven't played around with it yet myself, but try setting it to that mode and then playing some media. Then go somewhere, like YouTube, and try to play a video. If you can here both QT and YouTube, then it's definitely not WASAPI. But if you only hear QT going, there's a good chance that it is.
 
Sep 10, 2009 at 2:10 PM Post #5 of 81

krmathis

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Hard to say, but it sure would be nice if it did!
 
Sep 11, 2009 at 2:51 AM Post #7 of 81

thomaspf

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This test is not really determining bit perfect playback but exclusive access. You could still be getting bit perfect playback if only a single stream is playing.

Could someone with Itunes 9 try a DTS encoded WAV file into a receiver.

Cheers

Thomas
 
Sep 11, 2009 at 4:48 AM Post #8 of 81

lmf22

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CONFIRMED: iTunes 9 has bitperfect output (but not exclusive mode).

I did the DTS WAV file using the following set up:
Windows Vista 32 bit with SP1
Juli@ soundcard
Optical out
Panasonic home theater receiver
Quicktime setting 44.1KHz 24 bit
Windows Sound setting 44.1KHz 24 bit

The DTS WAV file is 44.1KHz, 16 bit, 5.1 channels and can be downloaded from http://www.sr.se/laddahem/MultiKanal...EST_011212.zip

The receiver was able to detect and play the DTS file. The display indicates that it is a DTS signal with 5.1 channel surround.

As soon as I play a YouTube video in Firefox, iTunes pauses the WAV file, and the sound of the YouTube video comes on. After stopping the video, I had to press Play in iTunes and the WAV file resumed; again the receiver detected the DTS signal.

When I adjusted either the iTunes or Windows volume control (to anything lower than 100%), the receiver did not detect the DTS signal and there was static noise. As soon as I put the volume control back to 100%, the receive once again detected the DTS signal.

This "automatic pause" when another stream is played also happens with regular MP3 and ALAC. While playing a song, I played a YouTube video, and the iTunes automatically pauses the song.

Also, I believe iTunes follow the Windows Sound sample rate setting, not the Quicktime setting. No matter what sample rate I set QuickTime to, it still plays back the WAV file. But, as soon as set the Windows Sound setting to 98KHz (the DTS WAV file is 44.1KHz), the receive did not detect the DTS signal and I heard static.

Can someone with other receivers test this? My receive is really old.
 
Sep 11, 2009 at 8:35 AM Post #10 of 81

Ra97oR

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Awesome news.
 

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