Hi Gian, For muting you could use pa_context_set_sink_mute_by_index ? To control volume, you need to set the volume on a pa_cvolume and then set the volume on the device with this struct. something like one sink_info* s (passed in) pa_volume_t new_volume = pa_sw_volume_from_linear(linear_input); pa_cvolume dev_vol; pa_cvolume_set(&dev_vol, s->volume.channels, new_volume); pa_operation_unref(pa_context_set_sink_volume_by_index(pulse_context, s->index, &dev_vol, NULL, NULL)); The docs on the wiki are pretty comprehensive about this. Conor On Tue, Feb 9, 2010 at 9:39 AM, Gian Lorenzo Meocci <<a href="mailto:glmeocci@gmail.com">glmeocci@gmail.com</a>> wrote: <div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi all, I have soume problem to control audio volume. I am using: pa_cvolume a; a.channels = channels; a.values[0] = PA_VOLUME_MUTED; a.values[1] = PA_VOLUME_MUTED; if(pa_cvolume_valid(&a)) qDebug() << "VALID"; pa_cvolume_mute(&a, channels); but volume remain set NORMAL why??? -- Ing. Gian Lorenzo Meocci <a href="http://www.meocci.it" target="_blank">http://www.meocci.it</a> _______________________________________________ pulseaudio-discuss mailing list <a href="mailto:pulseaudio-discuss@mail.0pointer.de">pulseaudio-discuss@mail.0pointer.de</a> <a href="https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss" target="_blank">https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss</a> </blockquote></div>