好多开发者提到，如何实现Android平台，多实例推送，多实例推送，有几种理解：
- 多路编码，多个实例分别推送到不同的RTMP URL（如Android采集板卡同时接2路出去）；
- 同一路编码，多个实例分别推送到不同的RTMP URL（如推送到内网、外网不同的RTMP服务器）；
- 部分路编码、部分路对接编码后的H.264/AAC数据，多个实例分别推送到不同的RTMP URL（混合推）。
目前，市面上的大多设计，都不够灵活，以下以“Android回调编码后的音视频数据”为例，推送一路原始的编码后的RTMP数据出去，然后，编码后的数据，回调到上层，再启动一个新的Publisher实例，推到新的RTMP地址（当然只是业务展示，实际可用于对接第三方系统，如GB28181或其他服务）：
具体流程如下：
- 设置音视频callback
对应接口：
/** * Set Audio Encoded Data Callback. * * @param audio_encoded_data_callback: Audio Encoded Data Callback. * * @return {0} if successful */ public native int SmartPublisherSetAudioEncodedDataCallback(long handle, Object audio_encoded_data_callback); /** * Set Video Encoded Data Callback. * * @param video_encoded_data_callback: Video Encoded Data Callback. * * @return {0} if successful */ public native int SmartPublisherSetVideoEncodedDataCallback(long handle, Object video_encoded_data_callback); 设置回调： libPublisher.SmartPublisherSetAudioEncodedDataCallback(publisherHandle, new PublisherAudioEncodedDataCallback()); libPublisher.SmartPublisherSetVideoEncodedDataCallback(publisherHandle, new PublisherVideoEncodedDataCallback());
- 实现 PublisherAudioEncodedDataCallback 和 PublisherVideoEncodedDataCallback：
class PublisherAudioEncodedDataCallback implements NTAudioDataCallback { private int audio_buffer_size = 0; private int param_info_size = 0; private ByteBuffer audio_buffer_ = null; private ByteBuffer parameter_info_ = null; @Override public ByteBuffer getAudioByteBuffer(int size) { //Log.i("getAudioByteBuffer", "size: " + size); if( size < 1 ) { return null; } if ( size <= audio_buffer_size && audio_buffer_ != null ) { return audio_buffer_; } audio_buffer_size = size + 512; audio_buffer_size = (audio_buffer_size+0xf) & (~0xf); audio_buffer_ = ByteBuffer.allocateDirect(audio_buffer_size); // Log.i("getAudioByteBuffer", "size: " + size + " buffer_size:" + audio_buffer_size); return audio_buffer_; } @Override public ByteBuffer getAudioParameterInfo(int size) { //Log.i("getAudioParameterInfo", "size: " + size); if(size < 1) { return null; } if ( size <= param_info_size && parameter_info_ != null ) { return parameter_info_; } param_info_size = size + 32; param_info_size = (param_info_size+0xf) & (~0xf); parameter_info_ = ByteBuffer.allocateDirect(param_info_size); //Log.i("getAudioParameterInfo", "size: " + size + " buffer_size:" + param_info_size); return parameter_info_; } public void onAudioDataCallback(int ret, int audio_codec_id, int sample_size, int is_key_frame, long timestamp, int sample_rate, int channel, int parameter_info_size, long reserve) { Log.i("onAudioDataCallback", "ret: " + ret + ", audio_codec_id: " + audio_codec_id + ", sample_size: " + sample_size + ", timestamp: " + timestamp + ",sample_rate:" + sample_rate + ",chn: " + channel + ", parameter_info_size:" + parameter_info_size); if ( audio_buffer_ == null) return; audio_buffer_.rewind(); if ( ret == 0 && publisherHandle2 != 0 ) { libPublisher.SmartPublisherPostAudioEncodedData(publisherHandle2, audio_codec_id, audio_buffer_, sample_size, is_key_frame, timestamp, parameter_info_, parameter_info_size); } } } class PublisherVideoEncodedDataCallback implements NTVideoDataCallback { private int video_buffer_size = 0; private ByteBuffer video_buffer_ = null; @Override public ByteBuffer getVideoByteBuffer(int size) { //Log.i("getVideoByteBuffer", "size: " + size); if( size < 1 ) { return null; } if ( size <= video_buffer_size && video_buffer_ != null ) { return video_buffer_; } video_buffer_size = size + 1024; video_buffer_size = (video_buffer_size+0xf) & (~0xf); video_buffer_ = ByteBuffer.allocateDirect(video_buffer_size); // Log.i("getVideoByteBuffer", "size: " + size + " buffer_size:" + video_buffer_size); return video_buffer_; } public void onVideoDataCallback(int ret, int video_codec_id, int sample_size, int is_key_frame, long timestamp, int width, int height, long presentation_timestamp) { Log.i("onVideoDataCallback", "ret: " + ret + ", video_codec_id: " + video_codec_id + ", sample_size: " + sample_size + ", is_key_frame: "+ is_key_frame + ", timestamp: " + timestamp + ",width: " + width + ", height:" + height + ",presentation_timestamp:" + presentation_timestamp); if ( video_buffer_ == null) return; video_buffer_.rewind(); if ( ret == 0 && publisherHandle2 !=0 ) { libPublisher.SmartPublisherPostVideoEncodedData(publisherHandle2, video_codec_id, video_buffer_, sample_size, is_key_frame, timestamp, presentation_timestamp); } } }
- 提供开始回调数据和停止回调数据接口：
/** * Start output Encoded Data(用于编码后的音视频数据回调) * * @return {0} if successful */ public native int SmartPublisherStartOutputEncodedData(long handle); /** * Stop output Encoded Data * * @return {0} if successful */ public native int SmartPublisherStopOutputEncodedData(long handle);
- 上层demo调用实例：
class ButtonEncodedDataCallbackListener implements OnClickListener { public void onClick(View v) { if (isEncodedDatacallbackRunning) { stopEncodedDataCallback(); if (!isPushing && !isRTSPPublisherRunning && !isRecording) { ConfigControlEnable(true); } btnEncodedDataCallback.setText("启动编码数据回调"); isEncodedDatacallbackRunning = false; if (publisherHandle2 != 0) { libPublisher.SmartPublisherStopPublisher(publisherHandle2); libPublisher.SmartPublisherClose(publisherHandle2); publisherHandle2 = 0; } return; } Log.i(TAG, "onClick start encoded data callback.."); if (libPublisher == null) return; if (!isPushing && !isRTSPPublisherRunning && !isRecording) { InitAndSetConfig(); } libPublisher.SmartPublisherSetAudioEncodedDataCallback(publisherHandle, new PublisherAudioEncodedDataCallback()); libPublisher.SmartPublisherSetVideoEncodedDataCallback(publisherHandle, new PublisherVideoEncodedDataCallback()); int startRet = libPublisher.SmartPublisherStartOutputEncodedData(publisherHandle); if (startRet != 0) { isEncodedDatacallbackRunning = false; Log.e(TAG, "Failed to start encoded data callback."); return; } if (!isPushing && !isRTSPPublisherRunning && !isRecording) { if (pushType == 0 || pushType == 1) { CheckInitAudioRecorder(); //enable pure video publisher.. } ConfigControlEnable(false); } btnEncodedDataCallback.setText("停止编码数据回调"); isEncodedDatacallbackRunning = true; int audio_opt = 2; int video_opt = 2; publisherHandle2 = libPublisher.SmartPublisherOpen(myContext, audio_opt, video_opt, videoWidth, videoHeight); if (publisherHandle2 == 0) { Log.e(TAG, "sdk open failed!"); return; } String relayUrl = "rtmp://player.daniulive.com:1935/hls/stream8888"; libPublisher.SmartPublisherSetURL(publisherHandle2, relayUrl); libPublisher.SmartPublisherStartPublisher(publisherHandle2); } } ; //停止编码后数据回调 private void stopEncodedDataCallback() { if(!isEncodedDatacallbackRunning) { return; } if (!isPushing && !isRTSPPublisherRunning && !isRecording) { if (audioRecord_ != null) { Log.i(TAG, "stopRecorder, call audioRecord_.StopRecording.."); audioRecord_.Stop(); if (audioRecordCallback_ != null) { audioRecord_.RemoveCallback(audioRecordCallback_); audioRecordCallback_ = null; } audioRecord_ = null; } } if (libPublisher != null) { libPublisher.SmartPublisherStopOutputEncodedData(publisherHandle); } if (!isPushing && !isRTSPPublisherRunning && !isRecording) { if (publisherHandle != 0) { if (libPublisher != null) { libPublisher.SmartPublisherClose(publisherHandle); publisherHandle = 0; } } } }
以上demo为了便于演示多实例效果，另启了个新的推送实例（对应新的publisherHandle），音视频编码后的数据，通过新的实例，调用编码后的音视频数据接口，继续推RTMP出去，从而实现多实例推送目的。
