Hi Colin, Yeah, I'm using TCP because the source audio is generated on a different machine from the one that has the USB sound card. I have a laptop with an internet music player on it, and I have a settop PC (pretty wimpy) that has a USB audio card connected to my stereo. I run the music player on my laptop because I want to control the audio from my laptop, and running the player on the settop and using vnc/nx is way to slow. So maybe the pulseaudio isn't doing any resampling work and is just churning to copy bytes around. Is there any optimizations I should have set up? In my /etc/pulse/default.pa I have: load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1; 192.168.0.0/16 port=8675 On the whole, I'm pretty happy with the setup. I'm trying to become an audio-snob :) and so wanted to make sure all my audio bits from the music player were getting to the sound card without unnecessary transformations. Josh On Sat, Jul 16, 2011 at 1:23 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote: > Hi Josh, > > 'Twas brillig, and Joshua Redstone at 16/07/11 18:50 did gyre and gimble: > > I'm running pulseaudio 0.9.22-24-g67d18 on Ubuntu 11.04, with a source > > at "s16le 2ch 44100Hz" and a USB card that is configured the same way. > > I see CPU usage at 25% - I would have thought that if the source/sink > > sample rates are identical and there is nothing else going on in the > > system, that pulseaudio would have no sample conversion work to do. > > Is there a setting to get more info on what it's doing? I've tried > > 'pulseaudio -vv' and I see: > > ...sniped... > > > D: alsa-util.c: rate : 44100 > > D: alsa-util.c: exact rate : 44100 (44100/1) > > > > and later on, when I play a stream: > > > > I: sink-input.c: Created input 0 "ALSA Playback" on > > > alsa_output.usb-Burr-Brown_from_TI_USB_Audio_CODEC-00-default.analog-stereo > > with sample spec s16le 2ch 44100Hz and channel map > > front-left,front-right > > I: sink-input.c: media.name <http://media.name> = "ALSA > Playback" > > I: sink-input.c: application.name <http://application.name> = > > "ALSA plug-in [chrome]" > > I: sink-input.c: native-protocol.peer = "TCP/IP client from > > 192.168.0.200:46969 <http://192.168.0.200:46969>" > > > > It seems like they match up exactly, or am I missing something? > > This is interesting..... > > The rates match up directly but it seems you are using TCP for > communications. This means that the client application (Chrome in this > case) is talking over a network socket to the daemon. > > This method is inefficient if you don't *have* to use it like this. > > In a typical setup PA client and server will both be run by the same > user. When this happens, the client can talk to the server via a local > domain socket which is more efficient. But more importantly than TCP vs. > local domain, one of the key things the latter enables is SHM data > transfer. Rather than copying audio data over the "wire" to the server, > SHM, allows the client to just share it's memory space with the server > allowing for lower overhead. > > I suspect you are using padevchooser which is basically cocking this all > up. This is one of the many reasons we deprecated padevchooser many > years ago and do not recommend it's usage. > > I still wouldn't expect such high CPU usage rates, so perhaps PA is > waking up more than it needs to to service your USB speakers still, but > getting a proper connection working is a good first step all the same. > > Col > > -- > > Colin Guthrie > gmane(at)colin.guthr.ie > http://colin.guthr.ie/ > > Day Job: > Tribalogic Limited [http://www.tribalogic.net/] > Open Source: > Mageia Contributor [http://www.mageia.org/] > PulseAudio Hacker [http://www.pulseaudio.org/] > Trac Hacker [http://trac.edgewall.org/] > > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss > -- Josh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20110716/e2166be4/attachment.html>
