Re: User-land driver for channel mapping
Re: User-land driver for channel mapping
- Subject: Re: User-land driver for channel mapping
- From: William Stewart <email@hidden>
- Date: Tue, 8 Apr 2008 12:35:04 -0700
On Apr 8, 2008, at 5:10 AM, Dave Addey wrote: Hi all,
I'm developing a user-land driver based on the SampleHardwarePlugin code, to work around a limitation in QuickTime. (I'm aware this is a less-than-elegant solution.) However, I'm not sure of the best approach for audio sync, and I'm confused by AudioTimeStamps, so I thought I'd post a few questions.
Why I'm doing this:
There is currently no way for QuickTime to play one stereo movie to two different pairs of outputs on a multi-channel audio device whilst applying separate volume levels to the different channels. (Radar feature request #4145662.)
My current workaround is to play two copies of a movie instead, with their timebases slaved together by QuickTime. Whilst this works on Tiger, it currently causes serious audio dropouts on Leopard (Radar bug #5615865), and on both platforms it necessitates a higher processor load (nearly 2x the load of one movie) than should be necessary.
Dave,
It seems to me that you are really wanting some pretty customised control over audio behaviour, so why are using QT to do this? QT is not really designed to provide these kinds of feature sets, and typically apps that are doing more than just basic playback will create their own audio engines so that they can have a finer degree of control over their rendering behaviour than QT can provide?
Bill |
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