Re: Audio passthrough fails after suspend
Re: Audio passthrough fails after suspend
- Subject: Re: Audio passthrough fails after suspend
- From: Jeff Moore <email@hidden>
- Date: Tue, 26 Oct 2004 16:18:38 -0700
I note that HALLab, QTPlayer and other apps don't have any problems
with keeping IO going across sleep/wake, so it seems to me that the
problem is a bug in AudioThru.
The likely reason for the bug is that the AudioThru sample code pays
very close attention to the time stamps. When sleep/wake happens, there
is obviously a discontinuity in time. From what I can see, the code in
AudioThru that pays attention to the time stamps isn't smart enough to
make sense of the new time line.
Feel free to file a bug against the sample code.
On Oct 26, 2004, at 12:58 PM, Peter Mueller wrote:
Hi,
Am Dienstag, 26.10.04 um 21:04 Uhr schrieb Jeff Moore:
In general, sleep is transparent to applications. It just happens.
From the HAL's perspective, it is, at worst, going to require a
resynch with the hardware. (This normally shows up as one or more
overload notifications from the HAL.)
Without more information, it's going to be hard to pinpoint what the
trouble might be. I'd start debugging this by looking at what exactly
is happenning at sleep and wake up. Try throwing some printf's around
to log what your code is doing across the break. Pay particular
attention to what notifications you are getting from the HAL and how
you are reacting to them.
On Oct 26, 2004, at 10:15 AM, Peter Mueller wrote:
The behaivour can be checked with the HAL/AudioThru example provided
by the audio sdk. Clicking on restart helps. Restart triggers stopping
the play thru via AudioDeviceRemoveIOProc etc. And then starting
playthru again by calling AudioDeviceAddIOProc.
Why is this necessary?
Interesting point: if another application plays someting (e.g. my ICQ
client) playthru works also again.
Any idea?
Peter
---
Peter Mueller
email@hidden
--
Jeff Moore
Core Audio
Apple
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