At Mon, 07 May 2012 16:15:06 +0200, Max Klein wrote:
Well, asym wouldn't be the answer. Basically you'll need to open two slave PCMs in one plugin. So, it's no simple filter-type plugin. It's doable, but not easy as it sounds, I guess.
Takashi, can you please further explain why asym is not the solution and what you see as a problem?
Well... Do you understand what asym plugin is supposed to do?
I am also trying to figure out if it would be possible to create such a plugin for ALSA? I am still searching for some good starting points on how to write an ALSA plugin...
Jean-Marc Valin (http://lists.linuxaudio.org/pipermail/linux-audio-dev/2005-June/012454.html) already released his work as part of speex but as far I know there is no plugin that has been made out of it?
For a good echo cancellation, you'll need both input and output streams, i.e. the recording source and the playback stream you are sending out. A normal plugin works just like a filter. Get one stream, process it, and output. But, now you need two streams in different directions in a single plugin instance.
asym doesn't do that. asym is just to pass through a slave PCM. The only job of asym plugin is to provide the different pass-thru slave PCM for each direction (input/output). Nothing more than that.
Takashi