On Thu, September 26, 2013 2:27 am, Tanu Kaskinen wrote: > On Wed, 2013-09-25 at 23:35 +1000, Patrick Shirkey wrote: >> On Tue, September 24, 2013 10:33 pm, Patrick Shirkey wrote: >> > >> > On Mon, September 23, 2013 6:11 pm, Tanu Kaskinen wrote: >> >> The audio is accumulating in some buffer, and the JACK sink in >> >> PulseAudio doesn't have any buffer, so it's not the sink. It could be >> >> some other buffer in PulseAudio, or it could be a buffer in ecasound. >> >> >> >> Saying that ecasound is configured with 64 frames/period isn't >> terribly >> >> informative, because I don't know how ecasound handles the transfer >> from >> >> the input to the output. Does it push the data immediately to the >> output >> >> when it gets something from the input, or are both directions >> callback >> >> based? If the former, then the data can accumulate in the stream >> buffer >> >> in PA, and if the latter, then there has to be an intermediate buffer >> >> between the input and the output in ecasound, and the data can >> >> accumulate there. >> >> >> > >> > I've asked for some more details on the ecasound list. >> > >> > If the PA stream buffer is kicking in, Is there any way I can verify >> if it >> > is happening? is there anything I can do to minimise that affect? >> > >> >> I had verification from the ecasound developer Kai Vehmanen that >> ecasound >> does not have an internal buffer that could be affecting the latency in >> this way. It just buffers 64 frames and if it can't keep up it will drop >> data and report an underun. In my tests there were just a few underruns >> over several hours so it appears safe to rule out ecasound. >> >> Does anyone have any suggestions for testing the PA Stream Buffer to >> check >> if it is a bottleneck in my test environment? > > Sorry, forgot to reply earlier. Yes, you can check the stream buffer > with "pactl list sink-inputs". The "Buffer Latency" field shows the > amount of audio in the stream buffer (not yet written to the sink). The > "Sink Latency" field shows the latency of the sink. The sum of these two > values is the full server-side latency for the stream. In addition to > the server-side latency, there's the transport latency between the > client and the server (very low for local streams). > Thanks for that info. Polling the output I see the results fluctuate over time in much the same way that the results from jack_iodelay fluctuate. I haven't tried to correlate them yet but here's a snapshot to give you a better idea of what is happening on this machine. ------------ Buffer Latency: 6666 usec Sink Latency: 3229 usec -- Buffer Latency: 5333 usec Sink Latency: 3791 usec -- Buffer Latency: 5333 usec Sink Latency: 3479 usec -- Buffer Latency: 5333 usec Sink Latency: 3791 usec -- Buffer Latency: 6666 usec Sink Latency: 3666 usec -- Buffer Latency: 8000 usec Sink Latency: 2791 usec -- Buffer Latency: 6666 usec Sink Latency: 2791 usec -- Buffer Latency: 6666 usec Sink Latency: 3041 usec -- Buffer Latency: 5333 usec Sink Latency: 3479 usec -- Buffer Latency: 6666 usec Sink Latency: 2958 usec -- Buffer Latency: 6666 usec Sink Latency: 3375 usec -- Buffer Latency: 8000 usec Sink Latency: 2833 usec -- Buffer Latency: 6666 usec Sink Latency: 3187 usec -- Buffer Latency: 6666 usec Sink Latency: 2937 usec -- Buffer Latency: 8000 usec Sink Latency: 2958 usec -- Buffer Latency: 8000 usec Sink Latency: 2708 usec -- Buffer Latency: 4000 usec Sink Latency: 2687 usec -- Buffer Latency: 5333 usec Sink Latency: 3500 usec -- Buffer Latency: 8000 usec Sink Latency: 3437 usec -- Buffer Latency: 6666 usec Sink Latency: 3645 usec -- Buffer Latency: 4000 usec Sink Latency: 3000 usec -- Buffer Latency: 5333 usec Sink Latency: 3666 usec -- Buffer Latency: 8000 usec Sink Latency: 3041 usec -- Buffer Latency: 2666 usec Sink Latency: 3416 usec -- Buffer Latency: 4000 usec Sink Latency: 2625 usec -- Buffer Latency: 8000 usec Sink Latency: 3375 usec -- Buffer Latency: 6666 usec Sink Latency: 2791 usec -- Buffer Latency: 6666 usec Sink Latency: 2750 usec -- Buffer Latency: 6666 usec Sink Latency: 3083 usec -- Buffer Latency: 6666 usec Sink Latency: 3333 usec -- Buffer Latency: 6666 usec Sink Latency: 3604 usec -- Buffer Latency: 6666 usec Sink Latency: 3166 usec -- Buffer Latency: 6666 usec Sink Latency: 3520 usec -- Buffer Latency: 8000 usec Sink Latency: 2895 usec -- Buffer Latency: 6666 usec Sink Latency: 3395 usec -- Buffer Latency: 6666 usec Sink Latency: 3083 usec -- Buffer Latency: 6666 usec Sink Latency: 2937 usec -- Buffer Latency: 6666 usec Sink Latency: 3604 usec -- Buffer Latency: 8000 usec Sink Latency: 3250 usec -- Buffer Latency: 8000 usec Sink Latency: 2687 usec -- Buffer Latency: 8000 usec Sink Latency: 3166 usec -- Buffer Latency: 6666 usec Sink Latency: 3687 usec -- Buffer Latency: 6666 usec Sink Latency: 3250 usec -- Buffer Latency: 6666 usec Sink Latency: 3062 usec -- Buffer Latency: 6666 usec Sink Latency: 3729 usec -- Buffer Latency: 6666 usec Sink Latency: 3729 usec -- Buffer Latency: 6666 usec Sink Latency: 2895 usec -- Buffer Latency: 6666 usec Sink Latency: 3395 usec -- Buffer Latency: 8000 usec Sink Latency: 3041 usec -- Buffer Latency: 8000 usec Sink Latency: 2708 usec -- Buffer Latency: 6666 usec Sink Latency: 3187 usec -- Buffer Latency: 6666 usec Sink Latency: 3250 usec -- Buffer Latency: 6666 usec Sink Latency: 3770 usec -- Buffer Latency: 4000 usec Sink Latency: 3687 usec -- Buffer Latency: 6666 usec Sink Latency: 3041 usec -- Buffer Latency: 6666 usec Sink Latency: 3437 usec -- Buffer Latency: 8000 usec Sink Latency: 3020 usec -- Buffer Latency: 6666 usec Sink Latency: 3166 usec -- Buffer Latency: 0 usec Sink Latency: 2916 usec -- Buffer Latency: 6666 usec Sink Latency: 3333 usec -- Buffer Latency: 6666 usec Sink Latency: 3250 usec -- Buffer Latency: 6666 usec Sink Latency: 3062 usec -- Buffer Latency: 6666 usec Sink Latency: 3520 usec -- Buffer Latency: 6666 usec Sink Latency: 3625 usec ------------ --------------- Sample Output --------------- Sink Input #1 Driver: protocol-native.c Owner Module: 9 Client: 5 Sink: 0 Sample Specification: s32le 2ch 48000Hz Channel Map: front-left,front-right Format: pcm, format.sample_format = "\"s32le\"" format.rate = "48000" format.channels = "2" format.channel_map = "\"front-left,front-right\"" Mute: no Volume: 0: 100% 1: 100% 0: 0.00 dB 1: 0.00 dB balance 0.00 Buffer Latency: 6666 usec Sink Latency: 3625 usec Resample method: copy Properties: media.name = "ALSA Playback" application.name = "ALSA plug-in [ecasound]" native-protocol.peer = "UNIX socket client" native-protocol.version = "26" application.process.id = "29246" application.process.user = "xxx" application.process.host = "xxx" application.process.binary = "ecasound" application.language = "C" window.x11.display = ":0" application.process.machine_id = "041faf23ca9cf5b3380f10bb508e20d3" application.process.session_id = "041faf23ca9cf5b3380f10bb508e20d3-1380185886.55549-100083828" module-stream-restore.id = "sink-input-by-application-name:ALSA plug-in [ecasound]" ----------------- -- Patrick Shirkey Boost Hardware Ltd
