'Twas brillig, and Lennart Poettering at 07/08/09 23:13 did gyre and gimble: > On Fri, 24.07.09 17:07, Colin Guthrie (gmane at colin.guthr.ie) wrote: > >> Hi Lennart, >> >> From IRC, but as you're busy and I suspect this wont get immediate >> attention, I'll post the details here for later :) >> >> <coling> mezcalero, found a reliable way to produce some nasty >> distortion that should not happen.... >> <coling> 1) >>> load-module module-remap-sink sink_name=mono >> master=<alsa sink name> channels=1 master_channel_map=front-left >> channel_map=mono >> <coling> 2) >>> load-module module-remap-sink sink_name=fakestereo >> master=mono channels=2 master_channel_map=mono,mono >> channel_map=front-left,front-right >> <coling> 3) PULSE_SINK=fakestereo paplay foo.wav >> <coling> That's it. >> <coling> Pretty nasty :s >> <coling> mezcalero, incidentally, the above process also causes an >> assert half the time too. >> <coling> E: sink.c: Assertion '!s->thread_info.rewind_requested' failed >> at pulsecore/sink.c:843, function pa_sink_render(). Aborting. > > This fix should be fixed now in r7d49163. Please verify. Seems to be OK now, thanks. :) > The distortion is probably caused because the handling of having two > mono channels is not what you expect. i.e. we probably just add them, > effectively amplifiyng the original signal 2x, which might easily > trigger clipping. > > If you run PA in debug mode the resamplers/remixers will dump a little > table that tells you how each input channel is added up for the output > channels. Could you please find out that table and check out if that > triggers your problem? (i.e. both input mono channels are multiplied > by factor 1.0 instead of 0.5?) > > Lennart Here's the full output. http://pastebin.com/me868948 From what I can see, yes when the second sink is loaded there is a factor of 1.0 involved. I presume there is no way to do what I originally wanted? (Incidentally I don't specifically want this... it was more an experiment for a user on the list who wanted to mix everything to the left channel but still have a balance control - he was deaf in one ear). Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited [http://www.tribalogic.net/] Open Source: Mandriva Linux Contributor [http://www.mandriva.com/] PulseAudio Hacker [http://www.pulseaudio.org/] Trac Hacker [http://trac.edgewall.org/]
