Re: Driver seems a little dizzy while running more thanonmediaplayer
Re: Driver seems a little dizzy while running more thanonmediaplayer
- Subject: Re: Driver seems a little dizzy while running more thanonmediaplayer
- From: "David Tan" <email@hidden>
- Date: Sat, 28 Feb 2009 10:57:01 +0800
Hi Jeff,
Thanks for your reply!
>> The easiest way to solve this problem is to use your DMA program to do a
small >> transfer, raise an interrupt and then you can take your first time
stamp since >> you know exactly where the hardware is at that point.
You're right. Actually I just found it inappropriate yesterday and corrected
it. With previous calculation, every time I start the audio stream, there'll
be a sharp sound firstly, then a slice of silence and finally the real
audio.
Now I push the first takeTimeStamp() after I start the DMA (DCL program for
Firewire) and the above issue disappear.
>> One other job that I think you'll need to do is to have an independent
idea >> about how the FireWire clock relates to the CPU clock. This is
something that >> has to be factored into your calculations that are
producing time stamps. I'm >> also told that this is a pretty tricky job,
but I'm not really all that sure >> about what is involved. This would be a
good reason to seek advice from a source >> more knowledgeable about
FireWire.
I think you point out a correct direction for me. DCL program provides a
TimeStamp command to receive DMA time stamp, which I don't use currently.
Frankly speaking, as current calculation works fine for single player, I
thought I don't have to use it. But now, I'll do some tests of it to see if
it's the key.
Sincerely yours,
David Tan
Dextrys Co., Ltd.
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