OpenShot Library | libopenshot 0.3.3
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AudioResampler.cpp
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1
9// Copyright (c) 2008-2019 OpenShot Studios, LLC
10//
11// SPDX-License-Identifier: LGPL-3.0-or-later
12
13#include "AudioResampler.h"
14
15using namespace std;
16using namespace openshot;
17
18// 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)
20{
21 buffer = NULL;
22 resample_source = NULL;
23 buffer_source = NULL;
24 num_of_samples = 0;
25 new_num_of_samples = 0;
26 dest_ratio = 0;
27 source_ratio = 0;
28 resampled_buffer = NULL;
29 isPrepared = false;
30
31 // Init buffer source
32 buffer_source = new AudioBufferSource(buffer);
33
34 // Init resampling source
35 resample_source = new juce::ResamplingAudioSource(buffer_source, false, numChannels);
36
37 // Init resampled buffer
38 resampled_buffer = new juce::AudioBuffer<float>(2, 1);
39 resampled_buffer->clear();
40
41 // Init callback buffer
42 resample_callback_buffer.buffer = resampled_buffer;
43 resample_callback_buffer.numSamples = 1;
44 resample_callback_buffer.startSample = 0;
45}
46
47// Descructor
49{
50 // Clean up
51 if (buffer_source)
52 delete buffer_source;
53 if (resample_source)
54 delete resample_source;
55 if (resampled_buffer)
56 delete resampled_buffer;
57}
58
59// Sets the audio buffer and updates the key settings
60void AudioResampler::SetBuffer(juce::AudioBuffer<float> *new_buffer, double sample_rate, double new_sample_rate)
61{
62 if (sample_rate <= 0)
63 sample_rate = 44100;
64 if (new_sample_rate <= 0)
65 new_sample_rate = 44100;
66
67 // Set the sample ratio (the ratio of sample rate change)
68 source_ratio = sample_rate / new_sample_rate;
69
70 // Call SetBuffer with ratio
71 SetBuffer(new_buffer, source_ratio);
72}
73
74// Sets the audio buffer and key settings
76{
77 // Update buffer & buffer source
78 buffer = new_buffer;
79 buffer_source->setBuffer(buffer);
80
81 // Set the sample ratio (the ratio of sample rate change)
82 source_ratio = ratio;
83 dest_ratio = 1.0 / ratio;
84 num_of_samples = buffer->getNumSamples();
85 new_num_of_samples = round(num_of_samples * dest_ratio);
86
87 // Set resample ratio
88 resample_source->setResamplingRatio(source_ratio);
89
90 // Prepare to play resample source
91 if (!isPrepared)
92 {
93 // Prepare to play the audio sources (and set the # of samples per chunk to a little more than expected)
94 resample_source->prepareToPlay(num_of_samples + 10, 0);
95 isPrepared = true;
96 }
97
98 // Resize buffer for the newly resampled data
99 resampled_buffer->setSize(buffer->getNumChannels(), new_num_of_samples, true, true, true);
100 resample_callback_buffer.numSamples = new_num_of_samples;
101 resample_callback_buffer.startSample = 0;
102 resample_callback_buffer.clearActiveBufferRegion();
103}
104
105// Get the resampled audio buffer
107{
108 // Resample the current frame's audio buffer (into the temp callback buffer)
109 resample_source->getNextAudioBlock(resample_callback_buffer);
110
111 // Return buffer pointer to this newly resampled buffer
112 return resampled_buffer;
113}
Header file for AudioResampler class.
This class is used to expose an AudioBuffer<float> as an AudioSource in JUCE.
void setBuffer(juce::AudioBuffer< float > *audio_buffer)
Update the internal buffer used by this source.
void SetBuffer(juce::AudioBuffer< float > *new_buffer, double sample_rate, double new_sample_rate)
Sets the audio buffer and key settings.
AudioResampler(int numChannels=2)
Default constructor.
juce::AudioBuffer< float > * GetResampledBuffer()
Get the resampled audio buffer.
This namespace is the default namespace for all code in the openshot library.
Definition Compressor.h:29