Playback hiccups with Quicktime and CoreAudio
Playback hiccups with Quicktime and CoreAudio
- Subject: Playback hiccups with Quicktime and CoreAudio
- From: Frank Vernon <email@hidden>
- Date: Thu, 20 Oct 2005 00:16:27 -0600
Hi all-
I'm having an issue with a modified version of Kurt Revis'
PlayBufferedSoundFile that I'm hoping someone here might be able to
shed some light on. I've already contacted Kurt and he's unaware of
the problem so I'm hoping someone on the list may have some insight
for me.
In a nutshell, the issue is that I'm seeing intermittent playback
hiccups when I pause the playback, 'rewind' to the head of the track,
and start playback over again. The hiccups seem to be correlated with
the position in the file where I had previously stopped the playback.
This leads me to believe that there may be some sort of file caching
issue with the OS that is temporarily delaying the QT decode process.
Is anyone aware of such issues with Quicktime decoding or playback
from file in general? If so, any suggestions on how to best deal with
them?
Here are few facts regarding my modifications to
PlayBufferedSoundFile that might have some bearing on the
situation... I have modified the QTSoundFilePlayer class to use an
AUGraph as its output so that I can add effects to the playback and
select alternate output devices. As a result of this change I have
also modified a few things like start/stop/pause/resume so they are
based on the operation of the graph rather than the quicktime decode
as in Kurt's original. There are also a number of other mods related
to more accurate tracking of the playback position (based on the
number of frames served to CoreAudio rather than the Quicktime decode
process) but nothing I believe to be related to this issue. I'd be
happy to post the source if it would help diagnose the problem.
It has already been recommended that I investigate moving to the new
AudioFile APIs as a possible replacement. Given that I need fairly
accurate tracking of playback position, accurate playback position
seeking, and the ability to configure an arbitrary output graph, can
anyone advise me if these new APIs would be appropriate for my
application?
Thanks-
Frank Vernon
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden