164 lines
4.4 KiB
C++
164 lines
4.4 KiB
C++
// Copyright (c) 2008, Rodrigo Braz Monteiro
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of the Aegisub Group nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// -----------------------------------------------------------------------------
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//
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// AEGISUB
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//
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// Website: http://aegisub.cellosoft.com
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// Contact: mailto:zeratul@cellosoft.com
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//
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#pragma once
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///////////
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// Headers
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#include "audio_provider_convert.h"
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///////////////
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// Constructor
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ConvertAudioProvider::ConvertAudioProvider(AudioProvider *src) {
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source = src;
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channels = 1;
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num_samples = source->GetNumSamples();
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sample_rate = source->GetSampleRate();
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bytes_per_sample = 2;
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sampleMult = 1;
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if (sample_rate < 16000) sampleMult = 4;
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else if (sample_rate < 32000) sampleMult = 2;
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sample_rate *= sampleMult;
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num_samples *= sampleMult;
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}
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//////////////
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// Destructor
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ConvertAudioProvider::~ConvertAudioProvider() {
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delete source;
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}
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/////////////////////
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// Convert to 16-bit
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void ConvertAudioProvider::Make16Bit(const char *src, short *dst, int64_t count) {
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for (int64_t i=0;i<count;i++) {
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dst[i] = (src[i]-128)*255;
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}
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}
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//////////////////////
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// Change sample rate
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// This requres 16-bit input
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void ConvertAudioProvider::ChangeSampleRate(const short *src, short *dst, int64_t count) {
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// Upsample by 2
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if (sampleMult == 2) {
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int64_t size = count/2;
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short cur;
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short next = 0;
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for (int64_t i=0;i<size;i++) {
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cur = next;
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next = *src++;
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*(dst++) = cur;
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*(dst++) = (cur+next)/2;
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}
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if (count%2) *(dst++) = next;
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}
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// Upsample by 4
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else if (sampleMult == 4) {
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int64_t size = count/4;
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short cur;
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short next = 0;
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for (int64_t i=0;i<size;i++) {
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cur = next;
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next = *(src++);
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*(dst++) = cur;
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*(dst++) = (cur*3+next)/4;
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*(dst++) = (cur+next)/2;
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*(dst++) = (cur+next*3)/4;
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}
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for (int i=0;i<count%4;i++) *(dst++) = next;
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}
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// Nothing to do (shouldn't really get here, but...)
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else if (sampleMult == 1) memcpy((void*)src,dst,count);
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}
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/////////////
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// Get audio
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void ConvertAudioProvider::GetAudio(void *destination, int64_t start, int64_t count) {
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// Bits per sample
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int srcBps = source->GetBytesPerSample();
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// Nothing to do
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if (sampleMult == 1 && srcBps == 2) {
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source->GetAudio(destination,start,count);
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}
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// Convert
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else {
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// Allocate buffers with sufficient size for the entire operation
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size_t fullSize = count;
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int64_t srcCount = count / sampleMult;
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short *buffer1 = NULL;
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short *buffer2 = NULL;
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short *last = NULL;
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// Read audio
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buffer1 = new short[fullSize];
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source->GetAudio(buffer1,start/sampleMult,srcCount);
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// Convert from 8-bit to 16-bit
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if (srcBps == 1) {
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if (sampleMult == 1) {
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Make16Bit((const char*)buffer1,(short*)destination,srcCount);
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}
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else {
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buffer2 = new short[fullSize];
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Make16Bit((const char*)buffer1,buffer2,srcCount);
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last = buffer2;
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}
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}
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// Already 16-bit
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else if (srcBps == 2) last = buffer1;
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// Convert sample rate
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if (sampleMult != 1) {
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ChangeSampleRate(last,(short*)destination,count);
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}
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delete [] buffer1;
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delete [] buffer2;
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}
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}
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