android将pcm byte[]通过Librtmp进行rtmp推流

需求

我们这边做的功能是智能戒指，戒指可以录音，然后app通过蓝牙连接，将音频的byte[]进行rtmp推流

技术

因为我们不涉及直播，也不涉及视频，工期也比较短，只是音频推流，所以没用更复杂的ffmpeg，使用了更简单的Librtmp，灵感来源于这篇文章
使用MediaCodec和RTMP做直播推流
但是这个的坏处是封装太深了，方便确实方便，不太好提取，我这边只是作为参考

思路

戒指上传的音频，或者手机录音的音频，都是pcm的，需要将先转换为aac格式的，所以必现先实现转换，然后再写入aac文件的时候，进行推流。
Librtmp Client for Android

PCMToAAC：

public class PCMToAAC {private String encodeType = MediaFormat.MIMETYPE_AUDIO_AAC;private static final int samples_per_frame = 2048;private MediaCodec mediaEncode;private MediaCodec.BufferInfo encodeBufferInfo;private ByteBuffer[] encodeInputBuffers;private ByteBuffer[] encodeOutputBuffers;private byte[] chunkAudio = new byte[0];private BufferedOutputStream out;File aacFile;File pcmFile;private RTMPMuxer rtmpMuxer=new RTMPMuxer();public PCMToAAC(String aacPath, String pcmPath) {aacFile = new File(aacPath);pcmFile = new File(pcmPath);if (!aacFile.exists()) {try {aacFile.getParentFile().mkdirs();aacFile.createNewFile();} catch (Exception e) {e.printStackTrace();}}try {out = new BufferedOutputStream(new FileOutputStream(aacFile, false));} catch (FileNotFoundException e) {e.printStackTrace();}initAACMediaEncode();rtmpMuxer.open("rtmp://4xxxx/live/stream",100,100);}public PCMToAAC() {aacFile = new File(com.smart.bing.utils.FileUtil.getSDPath(App.getInstance(),  "test.aac"));try{aacFile.delete();}catch (Exception e){e.printStackTrace();}if (!aacFile.exists()) {try {aacFile.getParentFile().mkdirs();aacFile.createNewFile();} catch (Exception e) {e.printStackTrace();}}try {out = new BufferedOutputStream(new FileOutputStream(aacFile, false));} catch (FileNotFoundException e) {e.printStackTrace();}initAACMediaEncode();rtmpMuxer.open("rtmp://xxxx/live/stream",100,100);}/*** 初始化AAC编码器*/private void initAACMediaEncode() {try {//参数对应-> mime type、采样率、声道数MediaFormat encodeFormat = MediaFormat.createAudioFormat(MediaFormat.MIMETYPE_AUDIO_AAC, 16000, 1);encodeFormat.setInteger(MediaFormat.KEY_BIT_RATE, 64000);//比特率encodeFormat.setInteger(MediaFormat.KEY_CHANNEL_COUNT, 1);encodeFormat.setInteger(MediaFormat.KEY_CHANNEL_MASK, AudioFormat.CHANNEL_IN_MONO);encodeFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);encodeFormat.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, samples_per_frame);//作用于inputBuffer的大小mediaEncode = MediaCodec.createEncoderByType(encodeType);mediaEncode.configure(encodeFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);} catch (IOException e) {e.printStackTrace();}if (mediaEncode == null) {return;}mediaEncode.start();encodeInputBuffers = mediaEncode.getInputBuffers();encodeOutputBuffers = mediaEncode.getOutputBuffers();encodeBufferInfo = new MediaCodec.BufferInfo();}/*** 编码PCM数据 得到AAC格式的音频文件*/public void dstAudioFormatFromPCM(byte[] pcmData) {int inputIndex;ByteBuffer inputBuffer;int outputIndex;ByteBuffer outputBuffer;int outBitSize;int outPacketSize;byte[] PCMAudio;PCMAudio = pcmData;encodeInputBuffers = mediaEncode.getInputBuffers();encodeOutputBuffers = mediaEncode.getOutputBuffers();encodeBufferInfo = new MediaCodec.BufferInfo();inputIndex = mediaEncode.dequeueInputBuffer(0);if (inputIndex != -1) {inputBuffer = encodeInputBuffers[inputIndex];inputBuffer.clear();inputBuffer.limit(PCMAudio.length);inputBuffer.put(PCMAudio);//PCM数据填充给inputBuffermediaEncode.queueInputBuffer(inputIndex, 0, PCMAudio.length, 0, 0);//通知编码器 编码outputIndex = mediaEncode.dequeueOutputBuffer(encodeBufferInfo, 0);while (outputIndex > 0) {outBitSize = encodeBufferInfo.size;outPacketSize = outBitSize + 7;//7为ADT头部的大小outputBuffer = encodeOutputBuffers[outputIndex];//拿到输出BufferoutputBuffer.position(encodeBufferInfo.offset);outputBuffer.limit(encodeBufferInfo.offset + outBitSize);chunkAudio = new byte[outPacketSize];addADTStoPacket(chunkAudio, outPacketSize);//添加ADTSoutputBuffer.get(chunkAudio, 7, outBitSize);//将编码得到的AAC数据 取出到byte[]中try {//录制aac音频文件，保存在手机内存中out.write(chunkAudio, 0, chunkAudio.length);rtmpMuxer.writeAudio(chunkAudio,0,chunkAudio.length,encodeBufferInfo.presentationTimeUs);Log.d("chunkAudio", Arrays.toString(chunkAudio));out.flush();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}outputBuffer.position(encodeBufferInfo.offset);mediaEncode.releaseOutputBuffer(outputIndex, false);outputIndex = mediaEncode.dequeueOutputBuffer(encodeBufferInfo, 0);}}}public void closeRtmp(){rtmpMuxer.close();}/*** 添加ADTS头** @param packet* @param packetLen*/private void addADTStoPacket(byte[] packet, int packetLen) {int profile = 2; // AAC LCint freqIdx = 8; // 16KHzint chanCfg = 1; // CPE// fill in ADTS datapacket[0] = (byte) 0xFF;packet[1] = (byte) 0xF1;packet[2] = (byte) (((profile - 1) << 6) + (freqIdx << 2) + (chanCfg >> 2));packet[3] = (byte) (((chanCfg & 3) << 6) + (packetLen >> 11));packet[4] = (byte) ((packetLen & 0x7FF) >> 3);packet[5] = (byte) (((packetLen & 7) << 5) + 0x1F);packet[6] = (byte) 0xFC;}public byte[] readInputStream() {InputStream inputStream = null;try {inputStream = new FileInputStream(pcmFile);} catch (FileNotFoundException e) {e.printStackTrace();}// 1.建立通道对象ByteArrayOutputStream outputStream = new ByteArrayOutputStream();// 2.定义存储空间byte[] buffer = new byte[1024];// 3.开始读文件int len = -1;try {if (inputStream != null) {while ((len = inputStream.read(buffer)) != -1) {// 将Buffer中的数据写到outputStream对象中
//                    outputStream.write(buffer, 0, len);dstAudioFormatFromPCM(buffer);Log.e("wqs+readInputStream", "readInputStream: " + buffer);}}// 4.关闭流outputStream.close();inputStream.close();} catch (IOException e) {e.printStackTrace();}return outputStream.toByteArray();}}

坑1：

rtmpMuxer.open(“rtmp://xxxx/live/stream”,100,100);

要放在外层，千万不要和rtmpMuxer.writeAudio放一起，要不然会卡死
坑2：
推流的地址，后边要加上音频流的名称，名字可以随便取，我这边叫stream
坑3：
这个PCMToAAC 涉及的操作较多，所以进入页面会有卡顿，可以在子线程初始化

使用

 PCMToAAC pcmToAAC;.....new Thread(new Runnable() {@Overridepublic void run() {pcmToAAC = new PCMToAAC();}}).start();@Overrideprotected void onDestroy() {super.onDestroy();pcmToAAC.closeRtmp();}/**
戒指录音回传
**/@Overridepublic void CONTROL_AUDIO(byte[] bytes) {new Thread(new Runnable() {@Overridepublic void run() {try {pcmToAAC.dstAudioFormatFromPCM(bytes);} catch (Exception e) {e.printStackTrace();}}}).start();}