On Fri, Oct 30, 2009 at 6:23 PM, Lennart Poettering <lennart at poettering.net>wrote: > Returning immediately *instead* of giving you 640 bytes of PCM? > > I mean, are you suggesting that pa_simple_read() is in fact *not* > returning 640 bytes? > Or is your confusion simply because you expect that at 44khz you > expect that calling pa_simple_read() for 640 bytes will block for > exactly 3.6 ms? That's not how things work. If it did you'd get > dropouts in the time between two _read() calls. > I definitely expected 640 bytes of PCM (~0.01s i thought) to be returned. I assumed that pa_simple_read() would block until I had that. This was the behavior in 0.9.14. Of course, it would be buffered, so I would expect from the time I opened the stream i would not have any data. In other words: 1. Open stream 2. sleep for x seconds 3. 1000000 bytes of data are in a buffer 4. i read 640 bytes and get 640 bytes (this takes microseconds) 5. Eventually my read catches up with the buffer The above situation is not what I am dealing with. This is not my situation at all. I would be fine if I eventually caught up with the buffer, but I never do, and as you pointed out, it's most likely because of latency. I need to get data *at least* every .1s. > > if you want to do time synchronization, then query for the *time*, > don't count samples. The time will be independant of buffering and so > on. In the simple API there is pa_simple_get_latency() which you can > query before you read something and which will then tell you how much > earlier what you will read next was actually recorded. > I don't really need time sync. If I drop packets, it's not *that* critical. But under normal operation i need to get audio every .1s. > If you use the complex API then you can use pa_stream_get_time() to > get a stream time, relative to the beginning of the stream. > > I'm trying to avoid the complex API because.... frankly.. it's really complex. Is there a way to set the latency using the simple API? -eric -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20091030/a4d40677/attachment.htm>
