Audio API: manage multiple-channel volume

You can now set the volume for multiple channels
independantly by using the "value=<1>,<2>..." syntax.

Signed-off-by: Manuel Bachmann <manuel.bachmann@iot.bzh>

4 files changed, 68 insertions, 21 deletions

diff --git a/plugins/audio/audio-alsa.c b/plugins/audio/audio-alsa.c
index 8e56e52d..1f54f244 100644
--- a/plugins/audio/audio-alsa.c
+++ b/plugins/audio/audio-alsa.c
@@ -19,6 +19,17 @@
 #include "audio-api.h"
 #include "audio-alsa.h"
 
+snd_mixer_selem_channel_id_t SCHANNELS[8] = {
+ SND_MIXER_SCHN_FRONT_LEFT,
+ SND_MIXER_SCHN_FRONT_RIGHT,
+ SND_MIXER_SCHN_FRONT_CENTER,
+ SND_MIXER_SCHN_REAR_LEFT,
+ SND_MIXER_SCHN_REAR_RIGHT,
+ SND_MIXER_SCHN_REAR_CENTER,
+ SND_MIXER_SCHN_SIDE_LEFT,
+ SND_MIXER_SCHN_SIDE_RIGHT
+};
+
 PUBLIC unsigned char _alsa_init (const char *name, audioCtxHandleT *ctx) {
 
     snd_pcm_t *dev;
@@ -28,7 +39,7 @@ PUBLIC unsigned char _alsa_init (const char *name, audioCtxHandleT *ctx) {
     snd_mixer_elem_t *mixer_elm;
     unsigned int rate = 22050;
     long vol, vol_min, vol_max;
-    int num;
+    int num, i;
 
     if (snd_pcm_open (&dev, name, SND_PCM_STREAM_PLAYBACK, 0) < 0)
         return 0;
@@ -105,7 +116,8 @@ PUBLIC unsigned char _alsa_init (const char *name, audioCtxHandleT *ctx) {
     dev_ctx[num]->thr_finished = 0;
 
     /* make the client context aware of current card state */
-    ctx->volume = _alsa_get_volume (num);
+    for (i = 0; i < 8; i++)
+        ctx->volume[i] = _alsa_get_volume (num, i);
     ctx->mute = _alsa_get_mute (num);
     ctx->idx = num;
 
@@ -155,22 +167,32 @@ PUBLIC void _alsa_stop (unsigned int num) {
     pthread_join(dev_ctx[num]->thr, NULL);
 }
 
-PUBLIC unsigned int _alsa_get_volume (unsigned int num) {
+PUBLIC int _alsa_get_volume (unsigned int num, unsigned int channel) {
 
     if (!dev_ctx || !dev_ctx[num] || !dev_ctx[num]->mixer_elm)
         return;
 
-    snd_mixer_selem_get_playback_volume (dev_ctx[num]->mixer_elm, SND_MIXER_SCHN_FRONT_LEFT, &dev_ctx[num]->vol);
+    snd_mixer_selem_get_playback_volume (dev_ctx[num]->mixer_elm, SCHANNELS[channel], &dev_ctx[num]->vol);
 
-    return (unsigned int)(dev_ctx[num]->vol*100)/dev_ctx[num]->vol_max;
+    return (int)(dev_ctx[num]->vol*100)/dev_ctx[num]->vol_max;
 }
 
-PUBLIC unsigned int _alsa_set_volume (unsigned int num, unsigned int vol) {
+PUBLIC void _alsa_set_volume (unsigned int num, unsigned int channel, int vol) {
 
-    if (!dev_ctx || !dev_ctx[num] || !dev_ctx[num]->mixer_elm || vol > 100)
+    if (!dev_ctx || !dev_ctx[num] || !dev_ctx[num]->mixer_elm ||
+        0 > vol > 100)
         return;
 
-   snd_mixer_selem_set_playback_volume_all (dev_ctx[num]->mixer_elm, (vol*dev_ctx[num]->vol_max)/100);
+    snd_mixer_selem_set_playback_volume (dev_ctx[num]->mixer_elm, SCHANNELS[channel], (vol*dev_ctx[num]->vol_max)/100);
+
+}
+
+PUBLIC void _alsa_set_volume_all (unsigned int num, int vol) {
+
+    if (!dev_ctx || !dev_ctx[num] || !dev_ctx[num]->mixer_elm ||
+        0 > vol > 100)
+
+    snd_mixer_selem_set_playback_volume_all (dev_ctx[num]->mixer_elm, (vol*dev_ctx[num]->vol_max)/100);
 }
 
 PUBLIC unsigned char _alsa_get_mute (unsigned int num) {
diff --git a/plugins/audio/audio-alsa.h b/plugins/audio/audio-alsa.h
index 56b4f55f..85545d57 100644
--- a/plugins/audio/audio-alsa.h
+++ b/plugins/audio/audio-alsa.h
@@ -39,7 +39,7 @@ struct dev_ctx {
 };
 
 STATIC void* _play_thread_fn (void *);
-PUBLIC unsigned int _alsa_get_volume (unsigned int);
+PUBLIC int _alsa_get_volume (unsigned int, unsigned int);
 PUBLIC unsigned char _alsa_get_mute (unsigned int);
 
 static struct dev_ctx **dev_ctx = NULL;
diff --git a/plugins/audio/audio-api.c b/plugins/audio/audio-api.c
index 60a5a962..915f8c6e 100644
--- a/plugins/audio/audio-api.c
+++ b/plugins/audio/audio-api.c
@@ -26,10 +26,12 @@
 STATIC audioCtxHandleT* initAudioCtx () {
 
     audioCtxHandleT *ctx;
+    int i;
 
     ctx = malloc (sizeof(audioCtxHandleT));
     ctx->idx = -1;
-    ctx->volume = 25;
+    for (i = 0; i < 8; i++)
+        ctx->volume[i] = 25;
     ctx->channels = 2;
     ctx->mute = 0;
     ctx->is_playing = 0;
@@ -82,28 +84,51 @@ STATIC json_object* volume (AFB_request *request) {      /* AFB_SESSION_CHECK */
     audioCtxHandleT *ctx = (audioCtxHandleT*)request->client->ctx;
     const char *value = getQueryValue (request, "value");
     json_object *jresp;
-    int volume;
+    int volume[8], i;
+    char *volume_i;
     char volume_str[256];
+    int len_str = 0;
 
     /* no "?value=" parameter : return current state */
     if (!value) {
-        ctx->volume = _alsa_get_volume (ctx->idx);
-        snprintf (volume_str, sizeof(volume_str), "%d", ctx->volume);
+        for (i = 0; i < 8; i++) {
+            ctx->volume[i] = _alsa_get_volume (ctx->idx, i);
+            snprintf (volume_str+len_str, sizeof(volume_str)-len_str, "%d,", ctx->volume[i]);
+            len_str = strlen(volume_str);
+        }
         jresp = json_object_new_object();
         json_object_object_add (jresp, "volume", json_object_new_string(volume_str));
     }
 
     /* "?value=" parameter, set volume */
     else {
-        volume = atoi (value);
-        if (100 < volume < 0) {
+        volume_i = strdup (value);
+        volume_i = strtok (volume_i, ",");
+        volume[0] = atoi (volume_i);
+
+        if (100 < volume[0] < 0) {
+            free (volume_i);
             request->errcode = MHD_HTTP_SERVICE_UNAVAILABLE;
             return (jsonNewMessage (AFB_FAIL, "Volume must be between 0 and 100"));
         }
-        ctx->volume = volume;
-        _alsa_set_volume (ctx->idx, ctx->volume);
-
-        snprintf (volume_str, sizeof(volume_str), "%d", ctx->volume);
+        ctx->volume[0] = volume[0];
+        _alsa_set_volume (ctx->idx, 0, ctx->volume[0]);
+        snprintf (volume_str, sizeof(volume_str), "%d,", ctx->volume[0]);
+
+        for (i = 1; i < 8; i++) {
+            volume_i = strtok (NULL, ",");
+            /* if there is only one value, set all channels to this one */
+            if (!volume_i && i == 1)
+               _alsa_set_volume_all (ctx->idx, ctx->volume[0]);
+            if (!volume_i || 100 < atoi(volume_i) < 0) {
+               ctx->volume[i] = _alsa_get_volume (ctx->idx, i);
+            } else {
+               ctx->volume[i] = atoi(volume_i);
+               _alsa_set_volume (ctx->idx, i, ctx->volume[i]);
+            }
+            len_str = strlen(volume_str);
+            snprintf (volume_str+len_str, sizeof(volume_str)-len_str, "%d,", ctx->volume[i]);
+        }
         jresp = json_object_new_object();
         json_object_object_add (jresp, "volume", json_object_new_string(volume_str));
     }
diff --git a/plugins/audio/audio-api.h b/plugins/audio/audio-api.h
index 12f70a8e..b6669ec9 100644
--- a/plugins/audio/audio-api.h
+++ b/plugins/audio/audio-api.h
@@ -36,10 +36,10 @@ typedef struct {
 typedef struct {
   audioDevT *radio;         /* pointer to client audio card          */
   int idx;                  /* audio card index within global array  */
-  unsigned int volume;      /* audio volume : 0-100                  */
+  int volume[8];            /* audio volume (8 channels) : 0-100     */
   unsigned int channels;    /* audio channels : 1(mono)/2(stereo)... */
   unsigned char mute;       /* audio muted : 0(false)/1(true)        */
-  unsigned char is_playing; /* audio is playing: 0(false)/1(true) */
+  unsigned char is_playing; /* audio is playing: 0(false)/1(true)    */
 } audioCtxHandleT;