Re: [OT] - Music pauses at random intervalls - SOLVED
Re: [OT] - Music pauses at random intervalls - SOLVED
- Subject: Re: [OT] - Music pauses at random intervalls - SOLVED
- From: "Roni Music" <email@hidden>
- Date: Thu, 10 May 2007 11:48:21 +0200
:
Hi,
Some users of my app which, is an audio player, reports that "often the
music will pause at random intervals".
I presume you mean there is a real stop in the audio for at least 100ms
or so, so it sounds more like a pause and less like a crackle.
The users have "new Mac Book" computers running (I guess) some of the
lattest versions of OS X.
You should confirm that. I have found some versions of OS X have
different latencies.
The users are playing regularr AIFF files or mp3 files decoded by
QuickTime.
What settings on a laptop could cause this problem?
It seems the operating system is taking over all CPU cycles and
preventing CoreAudio to work OK?
I've never experienced this problem on my 1 GHz PPC or my 2 GHz Dual
iMac
(my app have a quite a few users and the appa have used the same
playback "engine" for severall years).
I know this is sort of "off topic" and the information above is
minimall but still, someone might have some good info to share??
Audio droppouts are usually caused by threading problems (such as the
presence of locks in your audio processing thread), priority issues, CPU
or data starvation, hardware issues, or buffer-size mismatches. In my
experience, locking issues, and buffer-size mismatches usually result in
shorter dropouts that create clicks or crackles (of course, anything is
possible, it just that's what's common). CPU starvation is easy to check
for (ask the user to run activity monitor), and hardware issues often
effect more than one app, but it's definitely worth finding out what
hardware they use. By process of elimination, data starvation is my
guess. Is their drive going to sleep or something weird like that? It's
possible quicktime is reading ahead in huge chunks, or that it's
"tasking" efforts are blocking some other part of your app? Are your
buffers big enough (without being too big -- they need some RAM left
over!) and always available for reading? I don't know if that's any help,
but maybe it's something to think about.
Thanks for your respond.
It turned out I didn't use the "noCacheMask" when reading MP3 files (I use
my own MP3 decoder).
This has never mattered on my desktop Intel or PPC Mac but apparently
notebooks works different.
So problem solved
Rolf
bjorn
-----------------------------
Bjorn Roche
XO Wave
Digital Audio Production and Post-Production Software
http://www.xowave.com
http://blog.bjornroche.com
http://myspace.com/xowave
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