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Use rectangular channel mixing instead of shuffling mode.

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This fixes an issue where excess channels are not heard when the sound
source has more channels than the listener.
This commit is contained in:
David Reid
2021-07-04 13:37:16 +10:00
parent 2d8b0633a4
commit a99eac9f22
1 changed files with 82 additions and 18 deletions
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research/miniaudio_engine.h
+74 -10
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@@ -3294,10 +3294,22 @@ static ma_result ma_channel_map_apply_mono_in_f32(float* pFramesOut, const ma_ch
return MA_SUCCESS;
}
static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChannelMapOut, ma_uint32 channelsOut, const float* pFramesIn, const ma_channel* pChannelMapIn, ma_uint32 channelsIn, ma_uint64 frameCount)
static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChannelMapOut, ma_uint32 channelsOut, const float* pFramesIn, const ma_channel* pChannelMapIn, ma_uint32 channelsIn, ma_uint64 frameCount, ma_channel_mix_mode mode)
{
ma_bool32 passthrough = MA_FALSE;
if (channelsOut == channelsIn) {
if (pChannelMapOut == pChannelMapIn) {
passthrough = MA_TRUE;
} else {
if (ma_channel_map_equal(channelsOut, pChannelMapOut, pChannelMapIn)) {
passthrough = MA_TRUE;
}
}
}
/* Optimized Path: Passthrough */
if (channelsOut == channelsIn && pChannelMapOut == pChannelMapIn) {
if (passthrough) {
ma_copy_pcm_frames(pFramesOut, pFramesIn, frameCount, ma_format_f32, channelsOut);
return;
}
@@ -3314,13 +3326,11 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann
return;
}
/*
For now, we're doing channel conversion a bit different to the standard channel converter. Here
we're only going to do a shuffle. We can't do this if the channel count exceeds the maximum
channel count or else we won't be able to fit it in a stack-allocated shuffle table.
*/
if (channelsOut <= MA_MAX_CHANNELS) {
ma_result result;
if (mode == ma_channel_mix_mode_simple) {
ma_channel shuffleTable[MA_MAX_CHANNELS];
result = ma_channel_map_build_shuffle_table(pChannelMapIn, channelsIn, pChannelMapOut, channelsOut, shuffleTable);
@@ -3332,6 +3342,60 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann
if (result != MA_SUCCESS) {
return;
}
} else {
ma_uint32 iFrame;
ma_uint32 iChannelOut;
ma_uint32 iChannelIn;
float weights[32][32]; /* Do not use MA_MAX_CHANNELS here! */
/*
If we have a small enough number of channels, pre-compute the weights. Otherwise we'll just need to
fall back to a slower path because otherwise we'll run out of stack space.
*/
if (channelsIn <= ma_countof(weights) && channelsOut <= ma_countof(weights)) {
/* Pre-compute weights. */
for (iChannelOut = 0; iChannelOut < channelsOut; iChannelOut += 1) {
ma_channel channelOut = ma_channel_map_get_channel(pChannelMapOut, channelsOut, iChannelOut);
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
ma_channel channelIn = ma_channel_map_get_channel(pChannelMapIn, channelsIn, iChannelIn);
weights[iChannelOut][iChannelIn] = ma_calculate_channel_position_rectangular_weight(channelOut, channelIn);
}
}
for (iFrame = 0; iFrame < frameCount; iFrame += 1) {
for (iChannelOut = 0; iChannelOut < channelsOut; iChannelOut += 1) {
float accumulation = 0;
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
accumulation += pFramesIn[iChannelIn] * weights[iChannelOut][iChannelIn];
}
pFramesOut[iChannelOut] = accumulation;
}
pFramesOut += channelsOut;
pFramesIn += channelsIn;
}
} else {
/* Cannot pre-compute weights because not enough room in stack-allocated buffer. */
for (iFrame = 0; iFrame < frameCount; iFrame += 1) {
for (iChannelOut = 0; iChannelOut < channelsOut; iChannelOut += 1) {
float accumulation = 0;
ma_channel channelOut = ma_channel_map_get_channel(pChannelMapOut, channelsOut, iChannelOut);
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
ma_channel channelIn = ma_channel_map_get_channel(pChannelMapIn, channelsIn, iChannelIn);
accumulation += pFramesIn[iChannelIn] * ma_calculate_channel_position_rectangular_weight(channelOut, channelIn);
}
pFramesOut[iChannelOut] = accumulation;
}
pFramesOut += channelsOut;
pFramesIn += channelsIn;
}
}
}
} else {
/* Fall back to silence. If you hit this, what are you doing with so many channels?! */
ma_silence_pcm_frames(pFramesOut, frameCount, ma_format_f32, channelsOut);
@@ -11516,7 +11580,7 @@ MA_API ma_result ma_spatializer_process_pcm_frames(ma_spatializer* pSpatializer,
if (pSpatializer->config.channelsIn == pSpatializer->config.channelsOut) {
ma_copy_pcm_frames(pFramesOut, pFramesIn, frameCount, ma_format_f32, pSpatializer->config.channelsIn);
} else {
ma_channel_map_apply_f32((float*)pFramesOut, pChannelMapOut, pSpatializer->config.channelsOut, (const float*)pFramesIn, pChannelMapIn, pSpatializer->config.channelsIn, frameCount); /* Safe casts to float* because f32 is the only supported format. */
ma_channel_map_apply_f32((float*)pFramesOut, pChannelMapOut, pSpatializer->config.channelsOut, (const float*)pFramesIn, pChannelMapIn, pSpatializer->config.channelsIn, frameCount, ma_channel_mix_mode_rectangular); /* Safe casts to float* because f32 is the only supported format. */
}
/*
@@ -11766,7 +11830,7 @@ MA_API ma_result ma_spatializer_process_pcm_frames(ma_spatializer* pSpatializer,
}
/* Convert to our output channel count. */
ma_channel_map_apply_f32((float*)pFramesOut, pChannelMapOut, channelsOut, (const float*)pFramesIn, pChannelMapIn, channelsIn, frameCount);
ma_channel_map_apply_f32((float*)pFramesOut, pChannelMapOut, channelsOut, (const float*)pFramesIn, pChannelMapIn, channelsIn, frameCount, ma_channel_mix_mode_rectangular);
/*
Calculate our per-channel gains. We do this based on the normalized relative position of the sound and it's
@@ -12331,7 +12395,7 @@ static void ma_engine_node_process_pcm_frames__general(ma_engine_node* pEngineNo
ma_copy_pcm_frames(pRunningFramesOut, pWorkingBuffer, framesJustProcessedOut, ma_format_f32, channelsOut);
} else {
/* Channel conversion required. TODO: Add support for channel maps here. */
ma_channel_map_apply_f32(pRunningFramesOut, NULL, channelsOut, pWorkingBuffer, NULL, channelsIn, framesJustProcessedOut);
ma_channel_map_apply_f32(pRunningFramesOut, NULL, channelsOut, pWorkingBuffer, NULL, channelsIn, framesJustProcessedOut, ma_channel_mix_mode_simple);
}
}