Add a comment explaining the pulseaudio prop_filter

1 files changed, 4 insertions, 0 deletions

diff --git a/Alc/backends/pulseaudio.c b/Alc/backends/pulseaudio.c
index 61c7f4af..156f8ffd 100644
--- a/Alc/backends/pulseaudio.c
+++ b/Alc/backends/pulseaudio.c
@@ -1388,6 +1388,10 @@ ALCboolean alc_pulse_init(BackendFuncs *func_list)
                 *func_list = pulse_funcs;
                 ret = ALC_TRUE;
 
+                /* Some libraries (Phonon, Qt) set some pulseaudio properties
+                 * through environment variables, which causes all streams in
+                 * the process to inherit them. This attempts to filter those
+                 * properties out by setting them to 0-length data. */
                 prop_filter = pa_proplist_new();
                 pa_proplist_set(prop_filter, PA_PROP_MEDIA_ROLE, NULL, 0);
                 pa_proplist_set(prop_filter, "phonon.streamid", NULL, 0);