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miniaudio
Commit 89cc773c authored by David Reid's avatar David Reid
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Experimental optimizations for channel mapping.

parent 33854acc
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Showing with 71 additions and 11 deletions
miniaudio.h
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...@@ -52138,19 +52138,82 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann ...@@ -52138,19 +52138,82 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann
} }
} }
for (iFrame = 0; iFrame < frameCount; iFrame += 1) { iFrame = 0;
/* Experiment: Try an optimized unroll for some specific cases to see how it improves performance. RESULT: Good gains. */
if (channelsOut == 8) {
/* Experiment 2: Expand the inner loop to see what kind of different it makes. RESULT: Small, but worthwhile gain. */
if (channelsIn == 2) {
for (; iFrame < frameCount; iFrame += 1) {
float accumulation[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
accumulation[0] += pFramesIn[iFrame*2 + 0] * weights[0][0];
accumulation[1] += pFramesIn[iFrame*2 + 0] * weights[1][0];
accumulation[2] += pFramesIn[iFrame*2 + 0] * weights[2][0];
accumulation[3] += pFramesIn[iFrame*2 + 0] * weights[3][0];
accumulation[4] += pFramesIn[iFrame*2 + 0] * weights[4][0];
accumulation[5] += pFramesIn[iFrame*2 + 0] * weights[5][0];
accumulation[6] += pFramesIn[iFrame*2 + 0] * weights[6][0];
accumulation[7] += pFramesIn[iFrame*2 + 0] * weights[7][0];
accumulation[0] += pFramesIn[iFrame*2 + 1] * weights[0][1];
accumulation[1] += pFramesIn[iFrame*2 + 1] * weights[1][1];
accumulation[2] += pFramesIn[iFrame*2 + 1] * weights[2][1];
accumulation[3] += pFramesIn[iFrame*2 + 1] * weights[3][1];
accumulation[4] += pFramesIn[iFrame*2 + 1] * weights[4][1];
accumulation[5] += pFramesIn[iFrame*2 + 1] * weights[5][1];
accumulation[6] += pFramesIn[iFrame*2 + 1] * weights[6][1];
accumulation[7] += pFramesIn[iFrame*2 + 1] * weights[7][1];
pFramesOut[iFrame * 8 + 0] = accumulation[0];
pFramesOut[iFrame * 8 + 1] = accumulation[1];
pFramesOut[iFrame * 8 + 2] = accumulation[2];
pFramesOut[iFrame * 8 + 3] = accumulation[3];
pFramesOut[iFrame * 8 + 4] = accumulation[4];
pFramesOut[iFrame * 8 + 5] = accumulation[5];
pFramesOut[iFrame * 8 + 6] = accumulation[6];
pFramesOut[iFrame * 8 + 7] = accumulation[7];
}
} else {
/* When outputting to 8 channels, we can do everything in groups of two 4x SIMD operations. */
for (; iFrame < frameCount; iFrame += 1) {
float accumulation[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
accumulation[0] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[0][iChannelIn];
accumulation[1] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[1][iChannelIn];
accumulation[2] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[2][iChannelIn];
accumulation[3] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[3][iChannelIn];
accumulation[4] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[4][iChannelIn];
accumulation[5] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[5][iChannelIn];
accumulation[6] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[6][iChannelIn];
accumulation[7] += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[7][iChannelIn];
}
pFramesOut[iFrame * 8 + 0] = accumulation[0];
pFramesOut[iFrame * 8 + 1] = accumulation[1];
pFramesOut[iFrame * 8 + 2] = accumulation[2];
pFramesOut[iFrame * 8 + 3] = accumulation[3];
pFramesOut[iFrame * 8 + 4] = accumulation[4];
pFramesOut[iFrame * 8 + 5] = accumulation[5];
pFramesOut[iFrame * 8 + 6] = accumulation[6];
pFramesOut[iFrame * 8 + 7] = accumulation[7];
}
}
}
/* Leftover frames. */
for (; iFrame < frameCount; iFrame += 1) {
for (iChannelOut = 0; iChannelOut < channelsOut; iChannelOut += 1) { for (iChannelOut = 0; iChannelOut < channelsOut; iChannelOut += 1) {
float accumulation = 0; float accumulation = 0;
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) { for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
accumulation += pFramesIn[iChannelIn] * weights[iChannelOut][iChannelIn]; accumulation += pFramesIn[iFrame*channelsIn + iChannelIn] * weights[iChannelOut][iChannelIn];
} }
pFramesOut[iChannelOut] = accumulation; pFramesOut[iFrame*channelsOut + iChannelOut] = accumulation;
} }
pFramesOut += channelsOut;
pFramesIn += channelsIn;
} }
} else { } else {
/* Cannot pre-compute weights because not enough room in stack-allocated buffer. */ /* Cannot pre-compute weights because not enough room in stack-allocated buffer. */
...@@ -52161,14 +52224,11 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann ...@@ -52161,14 +52224,11 @@ static void ma_channel_map_apply_f32(float* pFramesOut, const ma_channel* pChann
for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) { for (iChannelIn = 0; iChannelIn < channelsIn; iChannelIn += 1) {
ma_channel channelIn = ma_channel_map_get_channel(pChannelMapIn, channelsIn, iChannelIn); ma_channel channelIn = ma_channel_map_get_channel(pChannelMapIn, channelsIn, iChannelIn);
accumulation += pFramesIn[iChannelIn] * ma_calculate_channel_position_rectangular_weight(channelOut, channelIn); accumulation += pFramesIn[iFrame*channelsIn + iChannelIn] * ma_calculate_channel_position_rectangular_weight(channelOut, channelIn);
} }
pFramesOut[iChannelOut] = accumulation; pFramesOut[iFrame*channelsOut + iChannelOut] = accumulation;
} }
pFramesOut += channelsOut;
pFramesIn += channelsIn;
} }
} }
} }
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