libao2: try to identify some audio outputs that have persistent volume

The mplayer frontend (specifically, mixer.c) needs to know this. If the
audio output doesn't remember the volume across reinitialization, the
frontend will restore the volume settings. There is also the assumption
that the volume setting isn't global in this case (i.e. changing it
won't change the volume of other applications or annoy the user
otherwise).

None of these changes have been tested. I'm guessing that ESD and NAS do
per-connection non-persistent volume settings.

1 files changed, 1 insertions, 0 deletions

diff --git a/libao2/ao_openal.c b/libao2/ao_openal.c
index e425b5769c..490aac0eb8 100644
--- a/libao2/ao_openal.c
+++ b/libao2/ao_openal.c
@@ -108,6 +108,7 @@ static int init(int rate, int channels, int format, int flags) {
   const opt_t subopts[] = {
     {NULL}
   };
+  global_ao->no_persistent_volume = true;
   if (subopt_parse(ao_subdevice, subopts) != 0) {
     print_help();
     return 0;