On Wed, 2011-09-07 at 14:20 +0800, Lu Guanqun wrote: > Hi Arun, > > I have several things unclear about passthrough support: I'm talking about this work at Linux Plumbers' Conference on Friday. If videos are available, I'll link to them -- hopefully that should make the motivation clear. > 1. Is it only useful when there's hardware decoding functionality > available? Can I simply test out passthrough with the current ALSA sound > card (some emulations possible)? Pretty much. The whole idea is that you're pushing out compressed audio, so something needs to decode it -- an a/v receiver that does AC3/DTS, or a Bluetooth headset that supports MP3 decode. > 2. As right now, ALSA only have PCM interface, how do we pass the > encoded data down? Do we have to use some other driver specific > interfaces? Vinod, recently posted some patches to add compression > interface for ALSA. Is that needed? No, that's not needed. We currently do IEC61937 payloading to make > 3. To be able to use passthrough, do we still need changes on Gstreamer? > Therefore people can simply use something like 'gst-launch xxx'. And > how's that status? The base stuff is in git master, and some of it is en route (https://bugzilla.gnome.org/show_bug.cgi?id=657179). Regards, Arun
