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Optimized the FlacDecoder to reuse buffers more efficiently.

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This commit is contained in:
Casey Langen 2016-05-28 20:56:59 -07:00
parent c4334ffc7f
commit 9815c3277c
2 changed files with 14 additions and 19 deletions
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32
src/contrib/flacdecoder/FlacDecoder.cpp
View File

@ -34,6 +34,7 @@
#include "stdafx.h"
#include "FlacDecoder.h"
#include <complex>
#include <iostream>
static inline void copy(float* dst, float* src, size_t count) {
#ifdef WIN32
@ -46,6 +47,7 @@ static inline void copy(float* dst, float* src, size_t count) {
FlacDecoder::FlacDecoder()
: decoder(NULL)
, outputBufferSize(0)
, outputBufferUsed(0)
, outputBuffer(NULL)
, channels(0)
, sampleRate(0)
@ -183,34 +185,26 @@ FLAC__StreamDecoderWriteStatus FlacDecoder::FlacWrite(
void *clientData)
{
FlacDecoder *fdec = (FlacDecoder*) clientData;
int sampleCount = fdec->channels * frame->header.blocksize;
int sampleCount = fdec->channels * frame->header.blocksize;
/* initialize the output buffer if it doesn't exist */
if (fdec->outputBufferSize == 0) {
if (sampleCount > fdec->outputBufferSize) {
delete fdec->outputBuffer;
fdec->outputBuffer = NULL;
fdec->outputBufferSize = 0;
fdec->outputBufferSize = sampleCount;
fdec->outputBuffer = new float[sampleCount];
}
/* if we already have a buffer with an offset, let's append to it. realloc
the buffer so there's enough room */
if (fdec->outputBuffer && fdec->outputBufferSize > 0) {
float *oldBuffer = fdec->outputBuffer;
fdec->outputBuffer = new float[sampleCount + fdec->outputBufferSize];
copy(fdec->outputBuffer, oldBuffer, fdec->outputBufferSize);
delete oldBuffer;
}
/* we need to convert the fixed point samples to floating point samples. figure
out the maximum amplitude of the fixed point samples based on the resolution */
float maxAmplitude = pow(2.0f, (fdec->bitsPerSample - 1));
float maxAmplitude = pow(2.0f, (fdec->bitsPerSample - 1));
/* run the conversion */
fdec->outputBufferUsed = 0;
for (unsigned int i = 0; i < frame->header.blocksize; ++i) {
for (int j = 0; j < fdec->channels; ++j) {
fdec->outputBuffer[fdec->outputBufferSize] = (((float) buffer[j][i]) / maxAmplitude);
fdec->outputBufferSize++;
fdec->outputBuffer[fdec->outputBufferUsed] = (((float) buffer[j][i]) / maxAmplitude);
fdec->outputBufferUsed++;
}
}
@ -237,10 +231,10 @@ bool FlacDecoder::GetBuffer(IBuffer *buffer) {
/* read the next chunk */
if (FLAC__stream_decoder_process_single(this->decoder)) {
if (this->outputBuffer && this->outputBufferSize > 0) {
buffer->SetSamples(this->outputBufferSize / this->channels);
copy(buffer->BufferPointer(), this->outputBuffer, this->outputBufferSize);
this->outputBufferSize = 0;
if (this->outputBuffer && this->outputBufferUsed > 0) {
buffer->SetSamples(this->outputBufferUsed / this->channels);
copy(buffer->BufferPointer(), this->outputBuffer, this->outputBufferUsed);
this->outputBufferUsed = 0; /* mark consumed */
return true;
}
}

1
src/contrib/flacdecoder/FlacDecoder.h
View File

@ -103,4 +103,5 @@ class FlacDecoder : public musik::core::audio::IDecoder {
float *outputBuffer;
unsigned long outputBufferSize;
unsigned long outputBufferUsed;
};