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Experimental optimzations to mono/stereo channel conversion.

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This commit is contained in:
David Reid
2019-08-31 08:02:25 +10:00
parent a04780f888
commit cc685b88ca
3 changed files with 286 additions and 18 deletions
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miniaudio.h
+58 -6
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@@ -862,12 +862,14 @@ typedef struct
struct ma_channel_router
{
ma_channel_router_config config;
ma_bool32 isPassthrough : 1;
ma_bool32 isSimpleShuffle : 1;
ma_bool32 useSSE2 : 1;
ma_bool32 useAVX2 : 1;
ma_bool32 useAVX512 : 1;
ma_bool32 useNEON : 1;
ma_bool32 isPassthrough : 1;
ma_bool32 isSimpleShuffle : 1;
ma_bool32 isSimpleMonoExpansion : 1;
ma_bool32 isStereoToMono : 1;
ma_bool32 useSSE2 : 1;
ma_bool32 useAVX2 : 1;
ma_bool32 useAVX512 : 1;
ma_bool32 useNEON : 1;
ma_uint8 shuffleTable[MA_MAX_CHANNELS];
};
@@ -29605,6 +29607,31 @@ ma_result ma_channel_router_init(const ma_channel_router_config* pConfig, ma_cha
}
}
/*
We can use a simple case for expanding the mono channel. This will when expanding a mono input into any output so long
as no LFE is present in the output.
*/
if (!pRouter->isPassthrough) {
if (pRouter->config.channelsIn == 1 && pRouter->config.channelMapIn[0] == MA_CHANNEL_MONO) {
/* Optimal case if no LFE is in the output channel map. */
pRouter->isSimpleMonoExpansion = MA_TRUE;
if (ma_channel_map_contains_channel_position(pRouter->config.channelsOut, pRouter->config.channelMapOut, MA_CHANNEL_LFE)) {
pRouter->isSimpleMonoExpansion = MA_FALSE;
}
}
}
/* Another optimized case is stereo to mono. */
if (!pRouter->isPassthrough) {
if (pRouter->config.channelsOut == 1 && pRouter->config.channelMapOut[0] == MA_CHANNEL_MONO && pRouter->config.channelsIn == 2) {
/* Optimal case if no LFE is in the input channel map. */
pRouter->isStereoToMono = MA_TRUE;
if (ma_channel_map_contains_channel_position(pRouter->config.channelsIn, pRouter->config.channelMapIn, MA_CHANNEL_LFE)) {
pRouter->isStereoToMono = MA_FALSE;
}
}
}
/*
Here is where we do a bit of pre-processing to know how each channel should be combined to make up the output. Rules:
@@ -29824,6 +29851,31 @@ void ma_channel_router__do_routing(ma_channel_router* pRouter, ma_uint64 frameCo
iChannelOut = pRouter->shuffleTable[iChannelIn];
ma_copy_memory_64(ppSamplesOut[iChannelOut], ppSamplesIn[iChannelIn], frameCount * sizeof(float));
}
} else if (pRouter->isSimpleMonoExpansion) {
/* Simple case for expanding from mono. */
if (pRouter->config.channelsOut == 2) {
ma_uint64 iFrame;
for (iFrame = 0; iFrame < frameCount; ++iFrame) {
ppSamplesOut[0][iFrame] = ppSamplesIn[0][iFrame];
ppSamplesOut[1][iFrame] = ppSamplesIn[0][iFrame];
}
} else {
for (iChannelOut = 0; iChannelOut < pRouter->config.channelsOut; ++iChannelOut) {
ma_uint64 iFrame;
for (iFrame = 0; iFrame < frameCount; ++iFrame) {
ppSamplesOut[iChannelOut][iFrame] = ppSamplesIn[0][iFrame];
}
}
}
} else if (pRouter->isStereoToMono) {
/* Simple case for going from stereo to mono. */
ma_assert(pRouter->config.channelsIn == 2);
ma_assert(pRouter->config.channelsOut == 1);
ma_uint64 iFrame;
for (iFrame = 0; iFrame < frameCount; ++iFrame) {
ppSamplesOut[0][iFrame] = (ppSamplesIn[0][iFrame] + ppSamplesIn[1][iFrame]) * 0.5f;
}
} else {
/* This is the more complicated case. Each of the output channels is accumulated with 0 or more input channels. */