diff options
| -rw-r--r-- | src/audio_core/cubeb_sink.cpp | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/src/audio_core/cubeb_sink.cpp b/src/audio_core/cubeb_sink.cpp index 7047ed9cf..c4e0e30fe 100644 --- a/src/audio_core/cubeb_sink.cpp +++ b/src/audio_core/cubeb_sink.cpp @@ -8,6 +8,7 @@ #include "audio_core/cubeb_sink.h" #include "audio_core/stream.h" #include "audio_core/time_stretch.h" +#include "common/assert.h" #include "common/logging/log.h" #include "common/ring_buffer.h" #include "core/settings.h" @@ -65,12 +66,25 @@ public: void EnqueueSamples(u32 source_num_channels, const std::vector<s16>& samples) override { if (source_num_channels > num_channels) { // Downsample 6 channels to 2 + ASSERT_MSG(source_num_channels == 6, "Channel count must be 6"); + std::vector<s16> buf; buf.reserve(samples.size() * num_channels / source_num_channels); for (std::size_t i = 0; i < samples.size(); i += source_num_channels) { - for (std::size_t ch = 0; ch < num_channels; ch++) { - buf.push_back(samples[i + ch]); - } + // Downmixing implementation taken from the ATSC standard + const s16 left{samples[i + 0]}; + const s16 right{samples[i + 1]}; + const s16 center{samples[i + 2]}; + const s16 surround_left{samples[i + 4]}; + const s16 surround_right{samples[i + 5]}; + // Not used in the ATSC reference implementation + [[maybe_unused]] const s16 low_frequency_effects { samples[i + 3] }; + + constexpr s32 clev{707}; // center mixing level coefficient + constexpr s32 slev{707}; // surround mixing level coefficient + + buf.push_back(left + (clev * center / 1000) + (slev * surround_left / 1000)); + buf.push_back(right + (clev * center / 1000) + (slev * surround_right / 1000)); } queue.Push(buf); return; |