commit db46b48d24e03f5bcb8de6d0ff852ec4153401e7
author Jean-Michel Trivi <jmtrivi@google.com> Mon Apr 23 11:29:26 2012 -0700
committer Jean-Michel Trivi <jmtrivi@google.com> Mon Apr 23 14:52:34 2012 -0700
tree 4d526d6d7e9b7fd92b46f3a8d48c2adfe7f54a63
parent 36513e357dfc6c53898d4b4f768c9fd4822f4653

Downmix support for 5.1 and quad with side channels

In DOWNMIX_TYPE_FOLD mode, add support for variants of quad and
 5.1 channel masks where the "side" channels are used instead of
 the "back" channels. These variants have the same channel order,
 so they can share the same downmix function.

Change-Id: I5f9cb7cb120927189de680c2a968d6136dc1fc43

media/libeffects/downmix/EffectDownmix.c

diff --git a/media/libeffects/downmix/EffectDownmix.c b/media/libeffects/downmix/EffectDownmix.c
index 5439b87..f37cd5e 100644
--- a/media/libeffects/downmix/EffectDownmix.c
+++ b/media/libeffects/downmix/EffectDownmix.c
@@ -24,6 +24,27 @@
 
 #define MINUS_3_DB_IN_Q19_12 2896 // -3dB = 0.707 * 2^12 = 2896
 
+typedef enum {
+    CHANNEL_MASK_SURROUND = AUDIO_CHANNEL_OUT_SURROUND,
+    CHANNEL_MASK_QUAD_BACK = AUDIO_CHANNEL_OUT_QUAD,
+    // like AUDIO_CHANNEL_OUT_QUAD with *_SIDE_* instead of *_BACK_*, same channel order
+    CHANNEL_MASK_QUAD_SIDE =
+            AUDIO_CHANNEL_OUT_FRONT_LEFT |
+            AUDIO_CHANNEL_OUT_FRONT_RIGHT |
+            AUDIO_CHANNEL_OUT_SIDE_LEFT |
+            AUDIO_CHANNEL_OUT_SIDE_RIGHT,
+    CHANNEL_MASK_5POINT1_BACK = AUDIO_CHANNEL_OUT_5POINT1,
+    // like AUDIO_CHANNEL_OUT_5POINT1 with *_SIDE_* instead of *_BACK_*, same channel order
+    CHANNEL_MASK_5POINT1_SIDE =
+            AUDIO_CHANNEL_OUT_FRONT_LEFT |
+            AUDIO_CHANNEL_OUT_FRONT_RIGHT |
+            AUDIO_CHANNEL_OUT_FRONT_CENTER |
+            AUDIO_CHANNEL_OUT_LOW_FREQUENCY |
+            AUDIO_CHANNEL_OUT_SIDE_LEFT |
+            AUDIO_CHANNEL_OUT_SIDE_RIGHT,
+    CHANNEL_MASK_7POINT1_SIDE_BACK = AUDIO_CHANNEL_OUT_7POINT1,
+} downmix_input_channel_mask_t;
+
 // effect_handle_t interface implementation for downmix effect
 const struct effect_interface_s gDownmixInterface = {
         Downmix_Process,
@@ -236,17 +257,19 @@
 
       case DOWNMIX_TYPE_FOLD:
         // optimize for the common formats
-        switch(pDwmModule->config.inputCfg.channels) {
-        case AUDIO_CHANNEL_OUT_QUAD:
+        switch((downmix_input_channel_mask_t)pDwmModule->config.inputCfg.channels) {
+        case CHANNEL_MASK_QUAD_BACK:
+        case CHANNEL_MASK_QUAD_SIDE:
             Downmix_foldFromQuad(pSrc, pDst, numFrames, accumulate);
             break;
-        case AUDIO_CHANNEL_OUT_SURROUND:
+        case CHANNEL_MASK_SURROUND:
             Downmix_foldFromSurround(pSrc, pDst, numFrames, accumulate);
             break;
-        case AUDIO_CHANNEL_OUT_5POINT1:
+        case CHANNEL_MASK_5POINT1_BACK:
+        case CHANNEL_MASK_5POINT1_SIDE:
             Downmix_foldFrom5Point1(pSrc, pDst, numFrames, accumulate);
             break;
-        case AUDIO_CHANNEL_OUT_7POINT1:
+        case CHANNEL_MASK_7POINT1_SIDE_BACK:
             Downmix_foldFrom7Point1(pSrc, pDst, numFrames, accumulate);
             break;
         default: