[MPlayer-dev-eng] [PATCH] use playback_switch with alsa for muting

[Matthias Lederhofer]

Hi,

I wrote a patch to libao2/ao_alsa.c which uses
snd_mixer_selem_set_playback_switch when the volume is set to 0.0.
This is the function intended for muting by alsa and I can still hear
a bit of the sound without it when I set master and my speakers to
full volume.
-------------- next part --------------
Index: libao2/ao_alsa.c
===================================================================
RCS file: /cvsroot/mplayer/main/libao2/ao_alsa.c,v
retrieving revision 1.20
diff -u -r1.20 ao_alsa.c
--- libao2/ao_alsa.c	25 Aug 2005 21:46:32 -0000	1.20
+++ libao2/ao_alsa.c	14 Nov 2005 23:08:24 -0000
@@ -197,6 +197,34 @@
 	}
 	mp_msg(MSGT_AO,MSGL_DBG2,"right=%li, pmin=%li, pmax=%li, mult=%f\n", 
 	       set_vol, pmin, pmax, f_multi);
+
+	//muting
+	if (snd_mixer_selem_has_playback_switch(elem)) {
+	  int status;
+	  if (snd_mixer_selem_has_playback_switch_joined(elem)) {
+	    snd_mixer_selem_get_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,&status);
+	    if (status && vol->left == 0.0 && vol->right == 0.0) {
+	      // mute
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,0);
+	    } else if (!status && (vol->left != 0.0 || vol->right != 0.0)) {
+	      // unmute
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,1);
+	    }
+	  } else {
+	    snd_mixer_selem_get_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,&status);
+	    if (status && vol->left == 0.0) {
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,0);
+	    } else if (!status && vol->left != 0.0) {
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_LEFT,1);
+	    }
+	    snd_mixer_selem_get_playback_switch(elem,SND_MIXER_SCHN_FRONT_RIGHT,&status);
+	    if (status && vol->right == 0.0) {
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_RIGHT,0);
+	    } else if (!status && vol->right != 0.0) {
+	      snd_mixer_selem_set_playback_switch(elem,SND_MIXER_SCHN_FRONT_RIGHT,1);
+	    }
+	  }
+	}
       }
       else {
 	snd_mixer_selem_get_playback_volume(elem, 0, &get_vol);