Re: iTunes 9: SRC bug fixed? SRC complexity?
Re: iTunes 9: SRC bug fixed? SRC complexity?
- Subject: Re: iTunes 9: SRC bug fixed? SRC complexity?
- From: Stephen Davis <email@hidden>
- Date: Sat, 12 Sep 2009 23:34:36 -0700
On Sep 12, 2009, at 6:56 AM, Bob Stern wrote:
Q #1:
Stephen Davis previously described the following behavior of iTunes
as a bug: "iTunes grabs the hardware sample rate at launch and runs
its internal processing chain at that rate for the life of the app."
(For example, in iTunes 7 & 8, suppose the user set the sample rate
of the default output device to 44.1 KHz and then launches iTunes.
Suppose the user then changed the sample rate of the output device
to 96 KHz and then played a 96 KHz track in iTunes. iTunes 7 & 8
would use SRC (AudioConverter) to convert the sample rate from 96 to
44.1 to match the sample rate when iTunes was launched, and then
CoreAudio would perform a second SRC step to convert it back to 96
to match the output device setting.)
Is this still true, or does iTunes now adapt to a change in the
sample rate of the default output device made by the user in Audio
MIDI Setup?
No, it does not. The fix didn't make it in for 9.0, other things took
priority. :-(
Unfortunately, I am not at liberty to say when it will make it in.
Specifically, without relaunching iTunes, can the user play
different tracks encoded at different sample rates, and prevent
iTunes and CoreAudio from performing SRC, if the user changes the
sample rate of the output device to match an individual track
*before* the user begins playing that track? Is the result
different if the user changes the output device sample rate *while*
iTunes is in the middle of playing a track?
Q #2:
I assume iTunes 9 continues to use AudioConverter with Quality set
to Max. What AudioConverter Complexity setting does iTunes 9 use:
Mastering (bats) or Normal (norm)?
It depends, but it never uses bats.
stephen
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