1 /*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "AudioSRC"
18
19 #include <stdint.h>
20 #include <string.h>
21 #include <sys/types.h>
22 #include <cutils/log.h>
23
24 #include "AudioResampler.h"
25 #include "AudioResamplerCubic.h"
26
27 namespace android {
28 // ----------------------------------------------------------------------------
29
init()30 void AudioResamplerCubic::init() {
31 memset(&left, 0, sizeof(state));
32 memset(&right, 0, sizeof(state));
33 }
34
resample(int32_t * out,size_t outFrameCount,AudioBufferProvider * provider)35 void AudioResamplerCubic::resample(int32_t* out, size_t outFrameCount,
36 AudioBufferProvider* provider) {
37
38 // should never happen, but we overflow if it does
39 // ALOG_ASSERT(outFrameCount < 32767);
40
41 // select the appropriate resampler
42 switch (mChannelCount) {
43 case 1:
44 resampleMono16(out, outFrameCount, provider);
45 break;
46 case 2:
47 resampleStereo16(out, outFrameCount, provider);
48 break;
49 }
50 }
51
resampleStereo16(int32_t * out,size_t outFrameCount,AudioBufferProvider * provider)52 void AudioResamplerCubic::resampleStereo16(int32_t* out, size_t outFrameCount,
53 AudioBufferProvider* provider) {
54
55 int32_t vl = mVolume[0];
56 int32_t vr = mVolume[1];
57
58 size_t inputIndex = mInputIndex;
59 uint32_t phaseFraction = mPhaseFraction;
60 uint32_t phaseIncrement = mPhaseIncrement;
61 size_t outputIndex = 0;
62 size_t outputSampleCount = outFrameCount * 2;
63 size_t inFrameCount = getInFrameCountRequired(outFrameCount);
64
65 // fetch first buffer
66 if (mBuffer.frameCount == 0) {
67 mBuffer.frameCount = inFrameCount;
68 provider->getNextBuffer(&mBuffer, mPTS);
69 if (mBuffer.raw == NULL) {
70 return;
71 }
72 // ALOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
73 }
74 int16_t *in = mBuffer.i16;
75
76 while (outputIndex < outputSampleCount) {
77 int32_t sample;
78 int32_t x;
79
80 // calculate output sample
81 x = phaseFraction >> kPreInterpShift;
82 out[outputIndex++] += vl * interp(&left, x);
83 out[outputIndex++] += vr * interp(&right, x);
84 // out[outputIndex++] += vr * in[inputIndex*2];
85
86 // increment phase
87 phaseFraction += phaseIncrement;
88 uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
89 phaseFraction &= kPhaseMask;
90
91 // time to fetch another sample
92 while (indexIncrement--) {
93
94 inputIndex++;
95 if (inputIndex == mBuffer.frameCount) {
96 inputIndex = 0;
97 provider->releaseBuffer(&mBuffer);
98 mBuffer.frameCount = inFrameCount;
99 provider->getNextBuffer(&mBuffer,
100 calculateOutputPTS(outputIndex / 2));
101 if (mBuffer.raw == NULL) {
102 goto save_state; // ugly, but efficient
103 }
104 in = mBuffer.i16;
105 // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
106 }
107
108 // advance sample state
109 advance(&left, in[inputIndex*2]);
110 advance(&right, in[inputIndex*2+1]);
111 }
112 }
113
114 save_state:
115 // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
116 mInputIndex = inputIndex;
117 mPhaseFraction = phaseFraction;
118 }
119
resampleMono16(int32_t * out,size_t outFrameCount,AudioBufferProvider * provider)120 void AudioResamplerCubic::resampleMono16(int32_t* out, size_t outFrameCount,
121 AudioBufferProvider* provider) {
122
123 int32_t vl = mVolume[0];
124 int32_t vr = mVolume[1];
125
126 size_t inputIndex = mInputIndex;
127 uint32_t phaseFraction = mPhaseFraction;
128 uint32_t phaseIncrement = mPhaseIncrement;
129 size_t outputIndex = 0;
130 size_t outputSampleCount = outFrameCount * 2;
131 size_t inFrameCount = getInFrameCountRequired(outFrameCount);
132
133 // fetch first buffer
134 if (mBuffer.frameCount == 0) {
135 mBuffer.frameCount = inFrameCount;
136 provider->getNextBuffer(&mBuffer, mPTS);
137 if (mBuffer.raw == NULL) {
138 return;
139 }
140 // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
141 }
142 int16_t *in = mBuffer.i16;
143
144 while (outputIndex < outputSampleCount) {
145 int32_t sample;
146 int32_t x;
147
148 // calculate output sample
149 x = phaseFraction >> kPreInterpShift;
150 sample = interp(&left, x);
151 out[outputIndex++] += vl * sample;
152 out[outputIndex++] += vr * sample;
153
154 // increment phase
155 phaseFraction += phaseIncrement;
156 uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
157 phaseFraction &= kPhaseMask;
158
159 // time to fetch another sample
160 while (indexIncrement--) {
161
162 inputIndex++;
163 if (inputIndex == mBuffer.frameCount) {
164 inputIndex = 0;
165 provider->releaseBuffer(&mBuffer);
166 mBuffer.frameCount = inFrameCount;
167 provider->getNextBuffer(&mBuffer,
168 calculateOutputPTS(outputIndex / 2));
169 if (mBuffer.raw == NULL) {
170 goto save_state; // ugly, but efficient
171 }
172 // ALOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
173 in = mBuffer.i16;
174 }
175
176 // advance sample state
177 advance(&left, in[inputIndex]);
178 }
179 }
180
181 save_state:
182 // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
183 mInputIndex = inputIndex;
184 mPhaseFraction = phaseFraction;
185 }
186
187 // ----------------------------------------------------------------------------
188 }
189 ; // namespace android
190