Multi-channels support for windows/mac/linux (#426)

* Add QUAD and QUAD_LFE layouts.

* Remove dual mono layout.

It makes no sense to have a case for those as the data structure
used (a bitmask) do not allow to represent this channel layout (a
channel can only be present once). As such it was a non-functional
layout

* Fix up cubeb_pulse compilation using C++ keyword.

* Remove the concept of preferred layout.

Channel layout is derived by the content being played. The concept of
preferred layout is meaningless. Either we have a layout defined, or
we don't. There's no in-between.

So we remove it.

* Remove CHANNEL_MONO concept.

* Add cubeb_sample_size convenience method.

* Rework cubeb_mixer.

This completely replace the existing remixer which had serious limitations:
1- Had no memory bound checks
2- Could only downmix 5.1 and 7.1 to stereo.

This mixer allows to convert from any sane layout to any other and work directly on interleaved samples.

This cubeb_mixer doesn't have an API compatible with the previous one.

This commit is non-fonctional, and was split for ease of review.

* Fix remixing on mac, windows and pulse backend.

* Make cubeb_mixer creation infallible.

Rather than ignore nonsensical layouts, we attempt to play it according to the stream channels count instead. The audio data will be played as-is, dropping the extra channels or inserting silence where needed.

* User proper sample size when calculating offsets.

Should the user data be of a different type to what the AudioUnit output is set to, we would have written outside the end of our allocated buffer.

* Fix input mixing and clarify frames vs samples terminology

* If a layout is unknown or invalid, always treat it as plain stereo or mono.

1 files changed, 13 insertions, 66 deletions

diff --git a/src/cubeb_mixer.h b/src/cubeb_mixer.h
index 51fb908..dd84b87 100644
--- a/src/cubeb_mixer.h
+++ b/src/cubeb_mixer.h
@@ -8,80 +8,27 @@
 #ifndef CUBEB_MIXER
 #define CUBEB_MIXER
 
-#include "cubeb/cubeb.h" // for cubeb_channel_layout ,CUBEB_CHANNEL_LAYOUT_MAPS and cubeb_stream_params.
-#include <stdbool.h>
+#include "cubeb/cubeb.h" // for cubeb_channel_layout and cubeb_stream_params.
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
-typedef enum {
-  CHANNEL_INVALID = -1,
-  CHANNEL_MONO = 0,
-  CHANNEL_LEFT,
-  CHANNEL_RIGHT,
-  CHANNEL_CENTER,
-  CHANNEL_LS,
-  CHANNEL_RS,
-  CHANNEL_RLS,
-  CHANNEL_RCENTER,
-  CHANNEL_RRS,
-  CHANNEL_LFE,
-  CHANNEL_UNMAPPED,
-  CHANNEL_MAX = 256 // Max number of supported channels.
-} cubeb_channel;
-
-static cubeb_channel const CHANNEL_INDEX_TO_ORDER[CUBEB_LAYOUT_MAX][CHANNEL_MAX] = {
-  { CHANNEL_INVALID },                                                                                            // UNDEFINED
-  { CHANNEL_LEFT, CHANNEL_RIGHT },                                                                                // DUAL_MONO
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_LFE },                                                                   // DUAL_MONO_LFE
-  { CHANNEL_MONO },                                                                                               // MONO
-  { CHANNEL_MONO, CHANNEL_LFE },                                                                                  // MONO_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT },                                                                                // STEREO
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_LFE },                                                                   // STEREO_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER },                                                                // 3F
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LFE },                                                   // 3F_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_RCENTER },                                                               // 2F1
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_LFE, CHANNEL_RCENTER },                                                  // 2F1_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_RCENTER },                                               // 3F1
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LFE, CHANNEL_RCENTER },                                  // 3F1_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_LS, CHANNEL_RS },                                                        // 2F2
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_LFE, CHANNEL_LS, CHANNEL_RS },                                           // 2F2_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LS, CHANNEL_RS },                                        // 3F2
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LFE, CHANNEL_LS, CHANNEL_RS },                           // 3F2_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LFE, CHANNEL_RCENTER, CHANNEL_LS, CHANNEL_RS },          // 3F3R_LFE
-  { CHANNEL_LEFT, CHANNEL_RIGHT, CHANNEL_CENTER, CHANNEL_LFE, CHANNEL_RLS, CHANNEL_RRS, CHANNEL_LS, CHANNEL_RS }  // 3F4_LFE
-  // When more channels are present, the stream is considered unmapped to a
-  // particular speaker set.
-};
-
-typedef struct {
-  unsigned int channels;
-  cubeb_channel map[CHANNEL_MAX];
-} cubeb_channel_map;
-
-cubeb_channel_layout cubeb_channel_map_to_layout(cubeb_channel_map const * channel_map);
-
-bool cubeb_should_upmix(cubeb_stream_params const * stream, cubeb_stream_params const * mixer);
-
-bool cubeb_should_downmix(cubeb_stream_params const * stream, cubeb_stream_params const * mixer);
-
-bool cubeb_should_mix(cubeb_stream_params const * stream, cubeb_stream_params const * mixer);
-
-typedef enum {
-  CUBEB_MIXER_DIRECTION_DOWNMIX = 0x01,
-  CUBEB_MIXER_DIRECTION_UPMIX   = 0x02,
-} cubeb_mixer_direction;
-
 typedef struct cubeb_mixer cubeb_mixer;
 cubeb_mixer * cubeb_mixer_create(cubeb_sample_format format,
-                                 unsigned char direction);
+                                 uint32_t in_channels,
+                                 cubeb_channel_layout in_layout,
+                                 uint32_t out_channels,
+                                 cubeb_channel_layout out_layout);
 void cubeb_mixer_destroy(cubeb_mixer * mixer);
-void cubeb_mixer_mix(cubeb_mixer * mixer, long frames,
-                     void * input_buffer, unsigned long input_buffer_length,
-                     void * output_buffer, unsigned long output_buffer_length,
-                     cubeb_stream_params const * stream_params,
-                     cubeb_stream_params const * mixer_params);
+int cubeb_mixer_mix(cubeb_mixer * mixer,
+                    size_t frames,
+                    void * input_buffer,
+                    size_t input_buffer_size,
+                    void * output_buffer,
+                    size_t output_buffer_size);
+
+unsigned int cubeb_channel_layout_nb_channels(cubeb_channel_layout channel_layout);
 
 #if defined(__cplusplus)
 }