Support multiple channels on Windows (#171)

* Multiple channel support on Windows

* Move up/down mixing code from cubeb_wasapi.cpp to standalone cubeb_mixer.cpp

1 files changed, 74 insertions, 6 deletions

diff --git a/include/cubeb/cubeb.h b/include/cubeb/cubeb.h
index 7a36b83..b435d16 100644
--- a/include/cubeb/cubeb.h
+++ b/include/cubeb/cubeb.h
@@ -176,12 +176,71 @@ typedef enum {
   CUBEB_LOG_VERBOSE = 2, /**< Verbose logging of callbacks, can have performance implications. */
 } cubeb_log_level;
 
+/** SMPTE channel layout (also known as wave order)
+ * DUAL-MONO      L   R
+ * DUAL-MONO-LFE  L   R   LFE
+ * MONO           M
+ * MONO-LFE       M   LFE
+ * STEREO         L   R
+ * STEREO-LFE     L   R   LFE
+ * 3F             L   R   C
+ * 3F-LFE         L   R   C    LFE
+ * 2F1            L   R   S
+ * 2F1-LFE        L   R   LFE  S
+ * 3F1            L   R   C    S
+ * 3F1-LFE        L   R   C    LFE S
+ * 2F2            L   R   LS   RS
+ * 2F2-LFE        L   R   LFE  LS   RS
+ * 3F2            L   R   C    LS   RS
+ * 3F2-LFE        L   R   C    LFE  LS   RS
+ * 3F3R-LFE       L   R   C    LFE  RC   LS   RS
+ * 3F4-LFE        L   R   C    LFE  RLS  RRS  LS   RS
+ *
+ * The abbreviation of channel name is defined in following table:
+ * Abbr  Channel name
+ * ---------------------------
+ * M     Mono
+ * L     Left
+ * R     Right
+ * C     Center
+ * LS    Left Surround
+ * RS    Right Surround
+ * RLS   Rear Left Surround
+ * RC    Rear Center
+ * RRS   Rear Right Surround
+ * LFE   Low Frequency Effects
+ */
+
+typedef enum {
+  CUBEB_LAYOUT_UNDEFINED, // Indicate the speaker's layout is undefined.
+  CUBEB_LAYOUT_DUAL_MONO,
+  CUBEB_LAYOUT_DUAL_MONO_LFE,
+  CUBEB_LAYOUT_MONO,
+  CUBEB_LAYOUT_MONO_LFE,
+  CUBEB_LAYOUT_STEREO,
+  CUBEB_LAYOUT_STEREO_LFE,
+  CUBEB_LAYOUT_3F,
+  CUBEB_LAYOUT_3F_LFE,
+  CUBEB_LAYOUT_2F1,
+  CUBEB_LAYOUT_2F1_LFE,
+  CUBEB_LAYOUT_3F1,
+  CUBEB_LAYOUT_3F1_LFE,
+  CUBEB_LAYOUT_2F2,
+  CUBEB_LAYOUT_2F2_LFE,
+  CUBEB_LAYOUT_3F2,
+  CUBEB_LAYOUT_3F2_LFE,
+  CUBEB_LAYOUT_3F3R_LFE,
+  CUBEB_LAYOUT_3F4_LFE,
+  CUBEB_LAYOUT_MAX
+} cubeb_channel_layout;
+
 /** Stream format initialization parameters. */
 typedef struct {
-  cubeb_sample_format format; /**< Requested sample format.  One of
-                                   #cubeb_sample_format. */
-  unsigned int rate;          /**< Requested sample rate.  Valid range is [1000, 192000]. */
-  unsigned int channels;      /**< Requested channel count.  Valid range is [1, 8]. */
+  cubeb_sample_format format;   /**< Requested sample format.  One of
+                                     #cubeb_sample_format. */
+  unsigned int rate;            /**< Requested sample rate.  Valid range is [1000, 192000]. */
+  unsigned int channels;        /**< Requested channel count.  Valid range is [1, 8]. */
+  cubeb_channel_layout layout;  /**< Requested channel layout. This must be consistent with the provided channels. */
 #if defined(__ANDROID__)
   cubeb_stream_type stream_type; /**< Used to map Android audio stream types */
 #endif
@@ -376,7 +435,7 @@ CUBEB_EXPORT int cubeb_get_max_channel_count(cubeb * context, uint32_t * max_cha
 
 /** Get the minimal latency value, in frames, that is guaranteed to work
     when creating a stream for the specified sample rate. This is platform,
-    hardware and backend dependant.
+    hardware and backend dependent.
     @param context A pointer to the cubeb context.
     @param params On some backends, the minimum achievable latency depends on
                   the characteristics of the stream.
@@ -390,7 +449,7 @@ CUBEB_EXPORT int cubeb_get_min_latency(cubeb * context,
                                        uint32_t * latency_frames);
 
 /** Get the preferred sample rate for this backend: this is hardware and
-    platform dependant, and can avoid resampling, and/or trigger fastpaths.
+    platform dependent, and can avoid resampling, and/or trigger fastpaths.
     @param context A pointer to the cubeb context.
     @param rate The samplerate (in Hz) the current configuration prefers.
     @retval CUBEB_OK
@@ -398,6 +457,15 @@ CUBEB_EXPORT int cubeb_get_min_latency(cubeb * context,
     @retval CUBEB_ERROR_NOT_SUPPORTED */
 CUBEB_EXPORT int cubeb_get_preferred_sample_rate(cubeb * context, uint32_t * rate);
 
+/** Get the preferred layout for this backend: this is hardware and
+    platform dependent.
+    @param context A pointer to the cubeb context.
+    @param layout The layout of the current speaker configuration.
+    @retval CUBEB_OK
+    @retval CUBEB_ERROR_INVALID_PARAMETER
+    @retval CUBEB_ERROR_NOT_SUPPORTED */
+CUBEB_EXPORT int cubeb_get_preferred_channel_layout(cubeb * context, cubeb_channel_layout * layout);
+
 /** Destroy an application context. This must be called after all stream have
  *  been destroyed.
     @param context A pointer to the cubeb context.*/