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/**
* @file
* @brief Source file for AudioResampler class
* @author Jonathan Thomas <jonathan@openshot.org>
*
* @section LICENSE
*
* Copyright (c) 2008-2014 OpenShot Studios, LLC
* <http://www.openshotstudios.com/>. This file is part of
* OpenShot Library (libopenshot), an open-source project dedicated to
* delivering high quality video editing and animation solutions to the
* world. For more information visit <http://www.openshot.org/>.
*
* OpenShot Library (libopenshot) is free software: you can redistribute it
* and/or modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* OpenShot Library (libopenshot) is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "../include/AudioResampler.h"
using namespace std;
using namespace openshot;
// Default constructor, max frames to cache is 20 // resample_source(NULL), buffer_source(NULL), num_of_samples(0), new_num_of_samples(0), dest_ratio(0), source_ratio(0), resampled_buffer(NULL), isPrepared(false)
AudioResampler::AudioResampler()
{
resample_source = NULL;
buffer_source = NULL;
num_of_samples = 0;
new_num_of_samples = 0;
dest_ratio = 0;
source_ratio = 0;
resampled_buffer = NULL;
isPrepared = false;
// Init buffer source
buffer_source = new AudioBufferSource(buffer);
// Init resampling source
resample_source = new ResamplingAudioSource(buffer_source, false, 2);
// Init resampled buffer
resampled_buffer = new AudioSampleBuffer(2, 1);
resampled_buffer->clear();
// Init callback buffer
resample_callback_buffer.buffer = resampled_buffer;
resample_callback_buffer.numSamples = 1;
resample_callback_buffer.startSample = 0;
}
// Descructor
AudioResampler::~AudioResampler()
{
// Clean up
if (buffer_source)
delete buffer_source;
if (resample_source)
delete resample_source;
if (resampled_buffer)
delete resampled_buffer;
}
// Sets the audio buffer and updates the key settings
void AudioResampler::SetBuffer(AudioSampleBuffer *new_buffer, double sample_rate, double new_sample_rate)
{
if (sample_rate <= 0)
sample_rate == 44100;
if (new_sample_rate <= 0)
new_sample_rate == 44100;
// Set the sample ratio (the ratio of sample rate change)
source_ratio = sample_rate / new_sample_rate;
// Call SetBuffer with ratio
SetBuffer(new_buffer, source_ratio);
}
// Sets the audio buffer and key settings
void AudioResampler::SetBuffer(AudioSampleBuffer *new_buffer, double ratio)
{
// Update buffer & buffer source
buffer = new_buffer;
buffer_source->setBuffer(buffer);
// Set the sample ratio (the ratio of sample rate change)
source_ratio = ratio;
dest_ratio = 1.0 / ratio;
num_of_samples = buffer->getNumSamples();
new_num_of_samples = round(num_of_samples * dest_ratio) - 1;
// Set resample ratio
resample_source->setResamplingRatio(source_ratio);
// Prepare to play resample source
if (!isPrepared)
{
// Prepare to play the audio sources (and set the # of samples per chunk to a little more than expected)
resample_source->prepareToPlay(num_of_samples + 10, 0);
isPrepared = true;
}
// Resize buffer for the newly resampled data
resampled_buffer->setSize(buffer->getNumChannels(), new_num_of_samples, true, true, true);
resample_callback_buffer.numSamples = new_num_of_samples;
resample_callback_buffer.startSample = 0;
resample_callback_buffer.clearActiveBufferRegion();
}
// Get the resampled audio buffer
AudioSampleBuffer* AudioResampler::GetResampledBuffer()
{
// Resample the current frame's audio buffer (into the temp callback buffer)
resample_source->getNextAudioBlock(resample_callback_buffer);
// Return buffer pointer to this newly resampled buffer
return resampled_buffer;
}
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