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, 5 insertions, 9 deletions

diff --git a/test/test_audio.cpp b/test/test_audio.cpp
index df51366..2e6c34a 100644
--- a/test/test_audio.cpp
+++ b/test/test_audio.cpp
@@ -94,7 +94,7 @@ int supports_channel_count(string backend_id, int nchannels)
     (backend_id != "opensl" && backend_id != "audiotrack");
 }
 
-int run_test(int num_channels, layout_info layout, int sampling_rate, int is_float)
+int run_test(int num_channels, int sampling_rate, int is_float)
 {
   int r = CUBEB_OK;
 
@@ -116,13 +116,13 @@ int run_test(int num_channels, layout_info layout, int sampling_rate, int is_flo
     return CUBEB_OK;
   }
 
-  fprintf(stderr, "Testing %d channel(s), layout: %s, %d Hz, %s (%s)\n", num_channels, layout.name, sampling_rate, is_float ? "float" : "short", cubeb_get_backend_id(ctx));
+  fprintf(stderr, "Testing %d channel(s), %d Hz, %s (%s)\n", num_channels, sampling_rate, is_float ? "float" : "short", cubeb_get_backend_id(ctx));
 
   cubeb_stream_params params;
   params.format = is_float ? CUBEB_SAMPLE_FLOAT32NE : CUBEB_SAMPLE_S16NE;
   params.rate = sampling_rate;
   params.channels = num_channels;
-  params.layout = layout.layout;
+  params.layout = CUBEB_LAYOUT_UNDEFINED;
   params.prefs = CUBEB_STREAM_PREF_NONE;
 
   synth_state synth(params.channels, params.rate);
@@ -246,12 +246,8 @@ TEST(cubeb, run_channel_rate_test)
     for(auto freq : freq_values) {
       ASSERT_TRUE(channels < MAX_NUM_CHANNELS);
       fprintf(stderr, "--------------------------\n");
-      for (auto layout : layout_infos) {
-        if (layout.channels == channels) {
-          ASSERT_EQ(run_test(channels, layout, freq, 0), CUBEB_OK);
-          ASSERT_EQ(run_test(channels, layout, freq, 1), CUBEB_OK);
-        }
-      }
+      ASSERT_EQ(run_test(channels, freq, 0), CUBEB_OK);
+      ASSERT_EQ(run_test(channels, freq, 1), CUBEB_OK);
     }
   }
 }