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Optimization pass on ma_gainer.

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David Reid
2022-11-19 13:20:25 +10:00
parent 45d6d5a2c3
commit b1967397dd
1 changed files with 114 additions and 0 deletions
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miniaudio.h
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@@ -47850,11 +47850,124 @@ MA_API ma_result ma_gainer_process_pcm_frames(ma_gainer* pGainer, void* pFramesO
ma_uint32 iChannel;
float* pFramesOutF32 = (float*)pFramesOut;
const float* pFramesInF32 = (const float*)pFramesIn;
ma_uint64 interpolatedFrameCount;
if (pGainer == NULL) {
return MA_INVALID_ARGS;
}
/*
We don't necessarily need to apply a linear interpolation for the entire frameCount frames. When
linear interpolation is not needed we can do a simple volume adjustment which will be more
efficient than a lerp with an alpha value of 1.
To do this, all we need to do is determine how many frames need to have a lerp applied. Then we
just process that number of frames with linear interpolation. After that we run on an optimized
path which just applies the new gains without a lerp.
*/
if (pGainer->t >= pGainer->config.smoothTimeInFrames) {
interpolatedFrameCount = 0;
} else {
interpolatedFrameCount = pGainer->t - pGainer->config.smoothTimeInFrames;
if (interpolatedFrameCount > frameCount) {
interpolatedFrameCount = frameCount;
}
}
/*
Start off with our interpolated frames. When we do this, we'll adjust frameCount and our pointers
so that the fast path can work naturally without consideration of the interpolated path.
*/
if (interpolatedFrameCount > 0) {
/* We can allow the input and output buffers to be null in which case we'll just update the internal timer. */
if (pFramesOut != NULL && pFramesIn != NULL) {
/*
All we're really doing here is moving the old gains towards the new gains. We don't want to
be modifying the gains inside the ma_gainer object because that will break things. Instead
we can make a copy here on the stack. For extreme channel counts we can fall back to a slower
implementation which just uses a standard lerp.
*/
float a = (float)pGainer->t / pGainer->config.smoothTimeInFrames;
float d = 1.0f / pGainer->config.smoothTimeInFrames;
if (pGainer->config.channels <= 32) {
float pRunningGain[32];
float pRunningGainDelta[32]; /* Could this be heap-allocated as part of the ma_gainer object? */
/* Initialize the running gain. */
for (iChannel = 0; iChannel < pGainer->config.channels; iChannel += 1) {
float t = pGainer->pOldGains[iChannel] - pGainer->pNewGains[iChannel];
pRunningGainDelta[iChannel] = t * d;
pRunningGain[iChannel] = pGainer->pOldGains[iChannel] + (t * a);
}
iFrame = 0;
/* Optimized loop unroll for stereo. This is mostly just experimenting with some SIMD ideas. It's not necessarily final. */
if (pGainer->config.channels == 2) {
ma_uint64 unrolledLoopCount = interpolatedFrameCount >> 1;
/* Expand some arrays so we can have a clean 4x SIMD operation in the loop. */
pRunningGainDelta[2] = pRunningGainDelta[0];
pRunningGainDelta[3] = pRunningGainDelta[1];
pRunningGain[2] = pRunningGain[0] + pRunningGainDelta[0];
pRunningGain[3] = pRunningGain[1] + pRunningGainDelta[1];
for (; iFrame < unrolledLoopCount; iFrame += 1) {
pFramesOutF32[iFrame*4 + 0] = pFramesInF32[iFrame*4 + 0] * pRunningGain[0];
pFramesOutF32[iFrame*4 + 1] = pFramesInF32[iFrame*4 + 1] * pRunningGain[1];
pFramesOutF32[iFrame*4 + 2] = pFramesInF32[iFrame*4 + 2] * pRunningGain[2];
pFramesOutF32[iFrame*4 + 3] = pFramesInF32[iFrame*4 + 3] * pRunningGain[3];
/* Move the running gain forward towards the new gain. */
pRunningGain[0] += pRunningGainDelta[0];
pRunningGain[1] += pRunningGainDelta[1];
pRunningGain[2] += pRunningGainDelta[2];
pRunningGain[3] += pRunningGainDelta[3];
}
iFrame = unrolledLoopCount << 1;
}
for (; iFrame < interpolatedFrameCount; iFrame += 1) {
for (iChannel = 0; iChannel < pGainer->config.channels; iChannel += 1) {
pFramesOutF32[iFrame*pGainer->config.channels + iChannel] = pFramesInF32[iFrame*pGainer->config.channels + iChannel] * pRunningGain[iChannel];
pRunningGain[iChannel] += pRunningGainDelta[iChannel];
}
}
} else {
/* Slower path for extreme channel counts where we can't fit enough on the stack. We could also move this to the heap as part of the ma_gainer object which might even be better since it'll only be updated when the gains actually change. */
for (iFrame = 0; iFrame < interpolatedFrameCount; iFrame += 1) {
for (iChannel = 0; iChannel < pGainer->config.channels; iChannel += 1) {
pFramesOutF32[iFrame*pGainer->config.channels + iChannel] = pFramesInF32[iFrame*pGainer->config.channels + iChannel] * ma_mix_f32_fast(pGainer->pOldGains[iChannel], pGainer->pNewGains[iChannel], a);
}
a += d;
}
}
}
/* Make sure the timer is updated. */
pGainer->t = (ma_uint32)ma_min(pGainer->t + interpolatedFrameCount, pGainer->config.smoothTimeInFrames);
/* Adjust our arguments so the next part can work normally. */
frameCount -= interpolatedFrameCount;
pFramesOut = ma_offset_ptr(pFramesOut, interpolatedFrameCount * sizeof(float));
pFramesIn = ma_offset_ptr(pFramesIn, interpolatedFrameCount * sizeof(float));
}
/* All we need to do here is apply the new gains using an optimized path. */
if (pFramesOut != NULL && pFramesIn != NULL) {
ma_copy_and_apply_volume_factor_per_channel_f32(pFramesOut, pFramesIn, frameCount, pGainer->config.channels, pGainer->pNewGains);
}
/* Now that some frames have been processed we need to make sure future changes to the gain are interpolated. */
if (pGainer->t == (ma_uint32)-1) {
pGainer->t = pGainer->config.smoothTimeInFrames;
}
#if 0
if (pGainer->t >= pGainer->config.smoothTimeInFrames) {
/* Fast path. No gain calculation required. */
ma_copy_and_apply_volume_factor_per_channel_f32(pFramesOutF32, pFramesInF32, frameCount, pGainer->config.channels, pGainer->pNewGains);
@@ -47903,6 +48016,7 @@ MA_API ma_result ma_gainer_process_pcm_frames(ma_gainer* pGainer, void* pFramesO
}
#endif
}
#endif
return MA_SUCCESS;
}