音视频开发之Android端native层播放音频三种方式

下面三种方式前两种区别不大，缺点是必须要等到系统加载差不多了才可以使用。Android系统启动时间很长，想要早点播放的话可以选择第三种，tinyalsa播放。

一. AudioTrack

final String TEST_NAME = "testPlaybackHeadPositionAfterFlush";
final int TEST_SR = 22050;
final int TEST_CONF = AudioFormat.CHANNEL_OUT_STEREO;
final int TEST_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
final int TEST_MODE = AudioTrack.MODE_STREAM;
final int TEST_STREAM_TYPE = AudioManager.STREAM_MUSIC;
 
//-------- initialization --------------
int minBuffSize = AudioTrack.getMinBufferSize(TEST_SR, TEST_CONF, TEST_FORMAT);
AudioTrack track = new AudioTrack(TEST_STREAM_TYPE, TEST_SR, TEST_CONF, TEST_FORMAT, minBuffSize, TEST_MODE);
byte data[] = new byte[minBuffSize/2];
//--------    test        --------------
track.write(data, 0, data.length);
track.write(data, 0, data.length);
track.play();
Thread.sleep(100);
track.stop();
track.flush();
//-------- tear down      --------------
track.release();

二. MediaPlayer

三. tinyalsa

struct pcm_config config;
struct pcm *pcm;
char *buffer;
unsigned int size, read_sz;
int num_read;
  
memset(&config, 0, sizeof(config));
config.channels = channels;
config.rate = rate;
config.period_size = period_size;
config.period_count = period_count;

config.format = PCM_FORMAT_S16_LE;
config.start_threshold = 0;
config.stop_threshold = 0;
config.silence_threshold = 0;

pcm = pcm_open(card, device, PCM_OUT, &config);
if (!pcm || !pcm_is_ready(pcm)) {
    
    
	fprintf(stderr, "Unable to open PCM device %u (%s)\n", device, pcm_get_error(pcm));
	return;
}

size = pcm_frames_to_bytes(pcm, pcm_get_buffer_size(pcm));
buffer = malloc(size);
do {
    
    
	read_sz = size < data_sz ? size : data_sz;
	num_read = fread(buffer, 1, read_sz, file);
	if (num_read > 0) {
    
    
	if (pcm_write(pcm, buffer, num_read)) {
    
    
		fprintf(stderr, "Error playing sample\n");
		break;
	}
	data_sz -= num_read;
} while (!close && num_read > 0 && data_sz > 0);

free(buffer);
pcm_close(pcm);

好像还有第四种，使用openGL ES，这个没怎么研究过。