tor, 04.03.2004 kl. 19.43 skrev Jaroslav Kysela: > Not really. I don't know, what you're trying to do. The silence extension > can be used to silence played area automatically from the interrupt > contents. If you set "silence_threshold" and "silence_size" to > buffer_size, then the whole _unused_ portion of the ring buffer will be > filled with silence. Perhaps, that's the behaviour what you expect.
Well, I was afraid that mode would not work well when I rewinded to add more sfx, I would risk getting any existing sfx in the buffer cleared. Or wouldn't I? > > Well, concerns of having to resort to messy application-side code to > > reimplement ALSA API features aside, there's also the issue of whether > > to rewind to before the playing position, or rather to forward to one > > buffer size after the playing position, to insert the silence, since for > > the ALSA API, there's a difference. But perhaps forward makes most > > sense. I guess I can do that. > > I don't understand. Well, for example, if the buffer size is 16384 frames, the app frame position is 24576, and the currently playing position is 20480 (so that snd_pcm_delay returns 4096). Now I want to clear the last 4096 frames that completed playing. Do I 1) call snd_pcm_rewind(8192), so that app frame position is 16384, which is logically behind play position (and in a xrun condition) or 2) call snd_pcm_forward(8192), so that app frame position is 32768, which is logically after play position (and seeking past potentially invalid data to get there) In both cases, begin_mmap should return a pointer at the beginning of the buffer and let me clear the desired area of it. But it might make a difference to xrun recovery, auto-silence, and who knows what else... But I'll just go for 2), it seems to be most straightforward to achieve with the current abstraction in our code. > > > It is wavetable synthesizer API not PCM API. This part of ALSA is still > > > in the development phase. > > > > But when that gets fully developed, would I have to use the rawmidi API > > to do this then? > > I think that sequencer API is more appropriate, but as I said, we don't > have a clear design at this time. It's also possible that we will hide > these things in alsa-lib and the kernel API will be hardware specific > using the hwdep interface. Hmm. ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
