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, 0 insertions, 9 deletions

diff --git a/src/cubeb-internal.h b/src/cubeb-internal.h
index 25bad3a..9b6199c 100644
--- a/src/cubeb-internal.h
+++ b/src/cubeb-internal.h
@@ -33,14 +33,6 @@ extern "C" {
 }
 #endif
 
-typedef struct {
-  char const * name;
-  unsigned int const channels;
-  cubeb_channel_layout const layout;
-} cubeb_layout_map;
-
-extern cubeb_layout_map const CUBEB_CHANNEL_LAYOUT_MAPS[CUBEB_LAYOUT_MAX];
-
 struct cubeb_ops {
   int (* init)(cubeb ** context, char const * context_name);
   char const * (* get_backend_id)(cubeb * context);
@@ -49,7 +41,6 @@ struct cubeb_ops {
                           cubeb_stream_params params,
                           uint32_t * latency_ms);
   int (* get_preferred_sample_rate)(cubeb * context, uint32_t * rate);
-  int (* get_preferred_channel_layout)(cubeb * context, cubeb_channel_layout * layout);
   int (* enumerate_devices)(cubeb * context, cubeb_device_type type,
                             cubeb_device_collection * collection);
   int (* device_collection_destroy)(cubeb * context,