DO NOT MERGE Update virtualizer effect interface for elevation angle

Update the comments in the virtualization effect parameters to
  reflect how elevation angles are part of the virtual speaker
  angle query.

Change-Id: Ic942cac40eea954a4f123729b92143a54518453c
(cherry picked from commit 046dddfb4fbdbd8eda6f4f8ad0218cfde2b9a09e)

diff --git a/audio_effects/include/audio_effects/effect_virtualizer.h b/audio_effects/include/audio_effects/effect_virtualizer.h
index 7631390..e429c5e 100644 (file)
--- a/audio_effects/include/audio_effects/effect_virtualizer.h
+++ b/audio_effects/include/audio_effects/effect_virtualizer.h
@@ -40,12 +40,18 @@ typedef enum
     //   parameters int32_t              VIRTUALIZER_PARAM_VIRTUAL_SPEAKER_ANGLES
     //              audio_channel_mask_t input channel mask
     //              audio_devices_t      audio output device
-    //   output     int32_t*             an array of length 2 * the number of channels in the mask
+    //   output     int32_t*             an array of length 3 * the number of channels in the mask
     //                                       where entries are the succession of the channel mask
     //                                       of each speaker (i.e. a single bit is selected in the
-    //                                       channel mask) followed by the angle value in degrees
+    //                                       channel mask) followed by the azimuth and the
+    //                                       elevation angles.
     //   status     int -EINVAL  if configuration is not supported or invalid or not forcing
     //                   0       if configuration is supported and the mode is forced
+    // notes:
+    // - all angles are expressed in degrees and are relative to the listener,
+    // - for azimuth: 0 is the direction the listener faces, 180 is behind the listener, and
+    //    -90 is to her/his left,
+    // - for elevation: 0 is the horizontal plane, +90 is above the listener, -90 is below.
     VIRTUALIZER_PARAM_VIRTUAL_SPEAKER_ANGLES,
     // used with EFFECT_CMD_SET_PARAM
     // format: