Adding SW volume control

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@4860 b3059339-0415-0410-9bf9-f77b7e298cf2

1 files changed, 133 insertions, 0 deletions

diff --git a/libao2/pl_volume.c b/libao2/pl_volume.c
new file mode 100644
index 0000000000..8c31cae92f
--- /dev/null
+++ b/libao2/pl_volume.c
@@ -0,0 +1,133 @@
+/* This audio output plugin changes the volume of the sound, and can
+   be used when the mixer doesn't support the PCM channel. The volume
+   is set in fixed steps between 0 - 2^8. */
+
+#define PLUGIN
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include "audio_out.h"
+#include "audio_plugin.h"
+#include "audio_plugin_internal.h"
+#include "afmt.h"
+
+static ao_info_t info =
+{
+        "Volume control audio plugin",
+        "volume",
+        "Anders",
+        ""
+};
+
+LIBAO_PLUGIN_EXTERN(volume)
+
+// local data
+typedef struct pl_volume_s
+{
+  uint16_t volume;   	// output volume level
+  int      inuse;     	// This plugin is in use TRUE, FALSE
+  int      format;	// sample fomat
+} pl_volume_t;
+
+static pl_volume_t pl_volume={0,0,0};
+
+// to set/get/query special features/parameters
+static int control(int cmd,int arg){
+  switch(cmd){
+  case AOCONTROL_PLUGIN_SET_LEN:
+    return CONTROL_OK;
+  case AOCONTROL_GET_VOLUME:{
+    if(pl_volume.inuse){
+      ((ao_control_vol_t *)arg)->right=((float)pl_volume.volume)/2.55;
+      ((ao_control_vol_t *)arg)->left=((float)pl_volume.volume)/2.55;
+      return CONTROL_OK;
+    }
+    else
+      return CONTROL_ERROR;
+  }
+  case AOCONTROL_SET_VOLUME:{
+    if(pl_volume.inuse){
+      // Calculate avarage between left and right
+      float vol =2.55*((((ao_control_vol_t *)arg)->right)+(((ao_control_vol_t *)arg)->left))/2;
+      pl_volume.volume=(uint16_t)vol;
+      // Volume must be between 0 and 255
+      if(vol > 255)
+	pl_volume.volume = 0xFF;
+      if(vol < 0)
+	pl_volume.volume = 0;
+      return CONTROL_OK;
+    }
+    else
+      return CONTROL_ERROR;
+  }
+  }
+  return CONTROL_UNKNOWN;
+}
+
+// open & setup audio device
+// return: 1=success 0=fail
+static int init(){
+  // Sanity sheck this plugin supports AFMT_U8 and AFMT_S16_LE
+  switch(ao_plugin_data.format){
+  case(AFMT_U8):
+  case(AFMT_S16_LE):
+    break;
+  default: 
+    fprintf(stderr,"[pl_volume] Audio format not yet suported \n");
+    return 0;
+  }
+  // Initialize volume to this value
+  pl_volume.volume=ao_plugin_cfg.pl_volume_volume;
+  pl_volume.format=ao_plugin_data.format;
+  /* The inuse flag is used in control to detremine if the return
+  value since that function always is called from ao_plugin regardless
+  of wether this plugin is in use or not. */
+  pl_volume.inuse=1;
+  // Tell the world what we are up to
+  printf("[pl_volume] Software volume control in use.\n");
+  return 1;
+}
+
+// close plugin
+static void uninit(){
+  pl_volume.inuse=0;
+}
+
+// empty buffers
+static void reset(){
+}
+
+// processes 'ao_plugin_data.len' bytes of 'data'
+// called for every block of data
+static int play(){
+  register int i=0;
+  // Change the volume.
+  switch(pl_volume.format){
+  case(AFMT_U8):{
+    register uint8_t* data=(uint8_t*)ao_plugin_data.data;
+    for(i=0;i<ao_plugin_data.len;i++){
+      data[i]=(((data[i]-128) * pl_volume.volume) >> 8) + 128;
+    }
+    break;
+  }
+  case(AFMT_S16_LE):{
+    register int len=ao_plugin_data.len>>1;
+    register int16_t* data=(int16_t*)ao_plugin_data.data;
+    for(i=0;i<len;i++)
+      data[i]=(data[i]* pl_volume.volume)>>8;
+    break;
+  }
+  default: 
+    return 0;
+  }
+  return 1;
+
+}
+
+
+
+
+