Thanks Lennart for the response. It took a few hours staring sideways at the API and a 'little' help from tanuk on the irc channel for me to see the path to the solution. Works perfectly now. All the best, Conor On Fri, Oct 16, 2009 at 3:49 AM, Lennart Poettering <lennart at poettering.net>wrote: > On Tue, 13.10.09 13:38, Forwind info (forward at forwind.net) wrote: > > Heya, > > > At the moment I am trying to write a simple gtk application which in > essence > > can detect this scenario : > > > > 'master' volume is muted. And at the same time a client application is > > attempting to play audio. > > > > I have been digging through the API and I can't find anything obvious > about > > the master volume. > > You should subescribe to sink changes with pa_context_subscribe(). Then > you need to enumerate the output sinks with > pa_context_get_sink_info_list(). Look for pa_sink_info::mute and > pa_sink_info::cvolume for the current mute state and the volume. Use > pa_cvolume_is_muted() on pa_sink_info::cvolume to easily check if all > channels of the volume are set to muted. i.e. something like this: > > muted = si->muted || pa_cvolume_is_muted(&si->cvolume); > > Then, wehn you get a subscription event simply ask for an update of > the pa_sink_info for that sink via > pa_context_get_sink_info_by_index(). > > That way you will be able to follow the mute status of all audio sinks > (aka "output devices"). Now if you also want to track the streams > connecting to them you do basically the same for the sink inputs (aka > "output streams"). The logic is very similar for that. If you want to > know which sink input (i.e. stream) connects to which sink > (i.e. output device) then compare pa_sink_input::sink and > pa_sink::index. > > Hope this is not too confusing. > > > I am using the Glib asynchronous api. So far I can query the server about > > the number channels and their respective volumes but I cannot query the > > overall master volume. > > There is no overall master volume, because we distinguish different > devices. The best you can get is the volume of each sink seperately. > > > I thought it would be a case of setting up a callback whereby any channel > > attempting to play a stream would notify a custom call back which would > then > > check if all channels are muted and then notify the GUI accordingly. > > > > another idea was to use PA_STREAM_START_MUTED. Connect to all streams and > on > > a playback event check if any has this stream state ? clutching at straws > to > > be honest. long time since I toyed with C API's. > > No need to bother with that flag. The introspection APIs should offer > all you need. > > Hope this helps! > > Lennart > > -- > Lennart Poettering Red Hat, Inc. > lennart [at] poettering [dot] net > http://0pointer.net/lennart/ GnuPG 0x1A015CC4 > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at mail.0pointer.de > https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20091016/4b091dd3/attachment.htm>
