On Thu, 2011-05-26 at 10:07 -0700, Baek Chang wrote: > I'm trying to use the echo cancellation module on my embedded platform > but it seems to be taking all the cpu usage and renders audio useless. > > > I'm continually seeing these messages: > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. This particular message is surprising. Was there a lot of feedback when you saw this? It's also possible that your clock is drifting a lot and is thus causing the echo canceller to give up. What hardware are you trying this on? > D: module-echo-cancel.c: diff -269 (43555 - 88163 + 44155) 0 0 9600 > 184 > E: module-echo-cancel.c: Playback after capture (-269), drop sink 84 > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > D: module-echo-cancel.c: diff 475 (42663 - 87687 + 45315) 0 0 9600 184 > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > D: module-echo-cancel.c: diff 168 (39254 - 87687 + 48410) 0 0 9600 191 > D: module-echo-cancel.c: diff -411 (38089 - 87687 + 49002) 0 0 9600 > 185 > E: module-echo-cancel.c: Playback after capture (-411), drop sink 112 > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > D: module-echo-cancel.c: diff 1491 (41407 - 87052 + 46961) 0 0 9600 > 175 > E: module-echo-cancel.c: playback too far ahead (1491), drop source > 260 > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > warning: The echo canceller started acting funny and got slapped > (reset). It swears it will behave now. > D: module-echo-cancel.c: diff -1166 (44921 - 88526 + 42252) 0 0 9600 > 187 > E: module-echo-cancel.c: Playback after capture (-1166), drop sink 244 > > > cpu is at 90-100% at the highest cpu scaling. > > > I was loading the module like so in my .pa conf file: > > > load-module module-echo-cancel source_name=echosource > source_master=pcm_input sink_name=echosink sink_master=pcm_output > rate=44100 channels=2 Do you really need to work with 44.1 kHz stereo streams? Your voip stack is probably working with 8 or 16 kHz audio and running in single channel mode would probably not make a difference either. It will, however, make a huge difference with respect to your CPU consumption. I pushed some more preprocessing code to module-echo-cancel yesterday, but there's a bit of a bug which I should be pushing a fix for by tomorrow. Once that's done, you can try it out by passing agc=1 / denoise=1 / echo_suppress=1. We're still looking at various potential improvements to get AEC working better, and I'll try to post a status in the coming weeks as things start to improve. You may also want to play with aec_method=adrian, which is an alternate canceller. It seems to learn faster than speex, but leaves a larger echo residue compared to once speex has had sufficient time to learn. Cheers, Arun
