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//
// Copyright (C) 2015 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "libmedia_playback.h"
#include <android-base/logging.h>
#include <media/AudioTrack.h>
#include <media/stagefright/MediaSource.h>
namespace android {
MediaBuffer* LibmediaPlayback::sine_data_buffer = NULL;
void LibmediaPlayback::Init() {
int kSampleRateHz = 8000;
int num_channels = 1;
source = new SineSource(kSampleRateHz, num_channels);
source->start(NULL); // Initialize with no parameters.
// Read data from source and store it in a buffer.
MediaSource::ReadOptions options;
source->read(&sine_data_buffer, &options);
}
size_t LibmediaPlayback::FillBuffer(void* data, size_t size) {
CHECK(data != NULL);
size = (size < sine_data_buffer->size()) ? size : sine_data_buffer->size();
memcpy(data, sine_data_buffer->data(), size);
return size;
}
void LibmediaPlayback::AudioCallback(int event, void* user, void* info) {
switch (event) {
case AudioTrack::EVENT_MORE_DATA: {
AudioTrack::Buffer* buffer = static_cast<AudioTrack::Buffer*>(info);
buffer->size = FillBuffer(buffer->raw, buffer->size);
break;
}
case AudioTrack::EVENT_STREAM_END: {
break;
}
default: {
fprintf(stderr, "Unexpected audio callback event\n");
break;
}
}
}
status_t LibmediaPlayback::Play() {
int kSampleRateHz = 8000;
audio_stream_type_t stream_type = AUDIO_STREAM_MUSIC;
audio_format_t audio_format = AUDIO_FORMAT_PCM_16_BIT;
audio_channel_mask_t audio_mask = AUDIO_CHANNEL_OUT_ALL;
size_t frame_count = 0; // Use default value for frame count.
audio_output_flags_t audio_output_flags = AUDIO_OUTPUT_FLAG_NONE;
AudioTrack* track = new AudioTrack(
stream_type, kSampleRateHz, audio_format, audio_mask, frame_count,
audio_output_flags, LibmediaPlayback::AudioCallback);
status_t status = track->initCheck();
if (status != OK) {
LOG(ERROR) << "Audio track initialization failed.";
return status;
}
float volume = 1;
track->setVolume(volume);
status = track->start();
if (status != OK) {
LOG(ERROR) << "Audio track failed to start.";
return status;
}
// Change volumes.
// The volume should decrease steadily and then increase steadily again.
for (float volume = 1; volume >= 0; volume -= 0.1) {
track->setVolume(volume);
sleep(1);
}
for (float volume = 0; volume <= 1; volume += 0.1) {
track->setVolume(volume);
sleep(1);
}
sleep(10);
track->stop();
// Free memory.
sine_data_buffer->release();
return status;
}
} // namespace android
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