Home | History | Annotate | Download | only in audio 
      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
      5  * use this file except in compliance with the License. You may obtain a copy of
      6  * 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, WITHOUT
     12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
     13  * License for the specific language governing permissions and limitations under
     14  * the License.
     15  */
     16 #include <math.h>
     17 #include <stdint.h>
     18 #include <stdlib.h>
     19 
     20 #include "Log.h"
     21 #include "audio/AudioSignalFactory.h"
     22 
     23 android::sp<Buffer> AudioSignalFactory::generateSineWave(AudioHardware::BytesPerSample BPS,
     24         int maxPositive, AudioHardware::SamplingRate samplingRate, int signalFreq,
     25         int samples,  bool stereo)
     26 {
     27     int bufferSize = samples * (stereo? 2 : 1) * BPS;
     28     android::sp<Buffer> buffer(new Buffer(bufferSize));
     29     // only 16bit signed
     30     ASSERT(BPS == AudioHardware::E2BPS);
     31     int16_t* data = reinterpret_cast<int16_t*>(buffer->getData());
     32     double multiplier = 2.0 * M_PI * (double)signalFreq / samplingRate;
     33     for (int i = 0; i < samples; i++) {
     34         double val = sin(multiplier * i) * maxPositive;
     35         *data = (int16_t)val;
     36         data++;
     37         if(stereo) {
     38             *data = (int16_t)val;
     39             data++;
     40         }
     41     }
     42     buffer->setSize(buffer->getCapacity());
     43     return buffer;
     44 }
     45 android::sp<Buffer> AudioSignalFactory::generateWhiteNoise(AudioHardware::BytesPerSample BPS,
     46         int maxPositive, int samples, bool stereo)
     47 {
     48     int bufferSize = samples * (stereo? 2 : 1) * BPS;
     49     android::sp<Buffer> buffer(new Buffer(bufferSize, bufferSize));
     50     // only 16bit signed
     51     ASSERT(BPS == AudioHardware::E2BPS);
     52     srand(123456);
     53     int16_t* data = reinterpret_cast<int16_t*>(buffer->getData());
     54     int middle = RAND_MAX / 2;
     55     double multiplier = (double)maxPositive / middle;
     56     for (int i = 0; i < samples; i++) {
     57         int val =  rand();
     58         val = (int16_t)((val - middle) * maxPositive / middle);
     59         *data = val;
     60         data++;
     61         if (stereo) {
     62             *data = val;
     63             data++;
     64         }
     65     }
     66     buffer->setSize(buffer->getCapacity());
     67     return buffer;
     68 }
     69 
     70 android::sp<Buffer> AudioSignalFactory::generateZeroSound(AudioHardware::BytesPerSample BPS,
     71         int samples, bool stereo)
     72 {
     73     int bufferSize = samples * (stereo? 2 : 1) * BPS;
     74     android::sp<Buffer> buffer(new Buffer(bufferSize, bufferSize));
     75     // only 16bit signed
     76     ASSERT(BPS == AudioHardware::E2BPS);
     77     int16_t* data = reinterpret_cast<int16_t*>(buffer->getData());
     78     for (int i = 0; i < samples; i++) {
     79         *data = 0;
     80         data++;
     81         if (stereo) {
     82             *data = 0;
     83             data++;
     84         }
     85     }
     86     buffer->setSize(buffer->getCapacity());
     87     return buffer;
     88 }
     89 
     90 
     91