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channel mapping: assign LFE channel weight

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If the LFE channel exists in the output channel map but not the input
channel map, we would previously just give it a weight of 0, which
caused it to not be filled.

This gives LFE a weight of 1.0f/$NumberOfSpatialChannels and basically
makes it omnidirectional.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
This commit is contained in:
Steven Noonan
2022-08-10 11:19:41 -07:00
committed by David Reid
parent 8f919e2beb
commit e327450d95
1 changed files with 52 additions and 3 deletions
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miniaudio.h
+52 -3
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@@ -5520,6 +5520,13 @@ The channel map buffer must have a capacity of at least `channels`.
*/
MA_API ma_bool32 ma_channel_map_contains_channel_position(ma_uint32 channels, const ma_channel* pChannelMap, ma_channel channelPosition);
/*
Find a channel position in the given channel map. Returns index of channel or -1 if not found.
The channel map buffer must have a capacity of at least `channels`.
*/
MA_API ma_int32 ma_channel_map_find_channel_position(ma_uint32 channels, const ma_channel* pChannelMap, ma_channel channelPosition);
/*
Generates a string representing the given channel map.
@@ -47707,6 +47714,7 @@ MA_API ma_vec3f ma_vec3f_cross(ma_vec3f a, ma_vec3f b)
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_mono_expansion_mode monoExpansionMode);
static ma_bool32 ma_is_spatial_channel_position(ma_channel channelPosition);
static ma_int32 ma_channel_map_num_spatial_channels(const ma_channel *pChannelMap, ma_uint32 channels);
#ifndef MA_DEFAULT_SPEED_OF_SOUND
@@ -50487,6 +50495,19 @@ static ma_int32 ma_channel_converter_float_to_fixed(float x)
return (ma_int32)(x * (1<<MA_CHANNEL_CONVERTER_FIXED_POINT_SHIFT));
}
static ma_int32 ma_channel_map_num_spatial_channels(const ma_channel* pChannelMap, ma_uint32 channels)
{
ma_int32 numSpatialChannels = 0;
ma_uint32 iChannel;
MA_ASSERT(pChannelMap != NULL);
MA_ASSERT(channels > 0);
for (iChannel = 0; iChannel < channels; ++iChannel) {
if (ma_is_spatial_channel_position(pChannelMap[iChannel]))
numSpatialChannels++;
}
return numSpatialChannels;
}
static ma_bool32 ma_is_spatial_channel_position(ma_channel channelPosition)
{
int i;
@@ -51338,6 +51359,29 @@ MA_API ma_result ma_channel_converter_init_preallocated(const ma_channel_convert
}
}
}
/* If LFE is in the output channel map but was not present in the input channel map, configure its weight now */
if (ma_channel_map_find_channel_position(pConverter->channelsIn, pConverter->pChannelMapIn, MA_CHANNEL_LFE) == -1) {
const ma_int32 numSpatialChannels = ma_channel_map_num_spatial_channels(pConverter->pChannelMapIn, pConverter->channelsIn);
const ma_int32 iChannelOutLFE = ma_channel_map_find_channel_position(pConverter->channelsOut, pConverter->pChannelMapOut, MA_CHANNEL_LFE);
if (numSpatialChannels > 0 && iChannelOutLFE != -1) {
const float weightForLFE = 1.0f / (float)numSpatialChannels;
for (iChannelIn = 0; iChannelIn < pConverter->channelsIn; ++iChannelIn) {
const ma_channel channelPosIn = ma_channel_map_get_channel(pConverter->pChannelMapIn, pConverter->channelsIn, iChannelIn);
if (ma_is_spatial_channel_position(channelPosIn)) {
if (pConverter->format == ma_format_f32) {
if (pConverter->weights.f32[iChannelIn][iChannelOutLFE] == 0) {
pConverter->weights.f32[iChannelIn][iChannelOutLFE] = weightForLFE;
}
} else {
if (pConverter->weights.s16[iChannelIn][iChannelOutLFE] == 0) {
pConverter->weights.s16[iChannelIn][iChannelOutLFE] = ma_channel_converter_float_to_fixed(weightForLFE);
}
}
}
}
}
}
} break;
}
}
@@ -53763,15 +53807,20 @@ MA_API ma_bool32 ma_channel_map_is_blank(const ma_channel* pChannelMap, ma_uint3
MA_API ma_bool32 ma_channel_map_contains_channel_position(ma_uint32 channels, const ma_channel* pChannelMap, ma_channel channelPosition)
{
ma_uint32 iChannel;
return ma_channel_map_find_channel_position(channels, pChannelMap, channelPosition) != -1 ? MA_TRUE : MA_FALSE;
}
MA_API ma_int32 ma_channel_map_find_channel_position(ma_uint32 channels, const ma_channel *pChannelMap, ma_channel channelPosition)
{
ma_int32 iChannel;
for (iChannel = 0; iChannel < channels; ++iChannel) {
if (ma_channel_map_get_channel(pChannelMap, channels, iChannel) == channelPosition) {
return MA_TRUE;
return iChannel;
}
}
return MA_FALSE;
return -1;
}
MA_API size_t ma_channel_map_to_string(const ma_channel* pChannelMap, ma_uint32 channels, char* pBufferOut, size_t bufferCap)