Hi Takashi,
On 06/10/14 10:45, Takashi Iwai wrote:
At Fri, 03 Oct 2014 17:24:22 -0500, Pierre-Louis Bossart wrote:
On 10/3/14, 7:00 AM, Tim Cussins wrote:
Hi Peirre,
The pcm hardware for the new platform can start rendering when a compare register matches a hw counter (driven by the audio clock). This allows for starting with frame-accurate timing.
Interesting. I wonder if you actually need a new extension for this, you could write the timestamp in an ALSA control and implement your .trigger function by using the contents of the control, i.e. delay the actual start. it wouldn't be generic but your hardware isn't either.
Well, your suggestion sounds really tricky. The trigger is supposed to trigger the stream immediately, and the delay isn't considered there in principle. The system can work with delays, but it's not in a form of the initial design.
I think some synchronized triggering mechanism is missing in API, too. There has been a similar request from others in the past (Digigram wanted to have such a feature), so maybe it's not so uncommon scenario.
This would be a good topic to be discussed in the upcoming audio mini-summit, but both of you won't be there, right?
I didn't have any plans to be at the mini-summit, but Glasgow isn't too far away...
Takashi