GB28181语音广播这块，我们依据GB/T28181-2016针对流程和实例代码，做过详细的描述，本次主要是探讨下，广播数据过来后，如何处理。
鉴于我们之前有非常成熟的RTMP|RTSP低延迟播放模块，语音广播数据过来后，调用startAudioPlay()，ntsOnInviteAudioBroadcastResponse()处理如下：
代码语言：javascript复制@Override
public void ntsOnInviteAudioBroadcastResponse(String sourceID, String targetID, int statusCode, PlaySessionDescription sessionDescription) {
handler_.postDelayed(new Runnable() {
@Override
public void run() {
Log.i(TAG, "ntsOnInviteAudioBroadcastResponse, statusCode:" status_code_ " sourceID:" source_id_ ", targetID:" target_id_);
boolean is_need_destory_rtp = true;
if (gb28181_agent_ != null ) {
boolean is_need_bye = 200==status_code_;
if (200 == status_code_ && session_description_ != null && rtp_receiver_handle_ != 0 ) {
MediaSessionDescription audio_des = session_description_.getAudioDescription();
SDPRtpMapAttribute audio_attr = null;
if (audio_des != null && audio_des.getRtpMapAttributes() != null && !audio_des.getRtpMapAttributes().isEmpty() )
audio_attr = audio_des.getRtpMapAttributes().get(0);
if ( audio_des != null && audio_attr != null ) {
lib_player_.SetRTPReceiverSSRC(rtp_receiver_handle_, audio_des.getSSRC());
lib_player_.SetRTPReceiverPayloadType(rtp_receiver_handle_, audio_attr.getPayloadType(),
audio_attr.getEncodingName(), 2, audio_attr.getClockRate());
// 如果是PCMA, SDK会默认填 采样率8000, 通道1, 其他音频编码需要手动填入
// lib_player_.SetRTPReceiverAudioSamplingRate(rtp_receiver_handle_, 8000);
// lib_player_.SetRTPReceiverAudioChannels(rtp_receiver_handle_, 1);
lib_player_.SetRTPReceiverRemoteAddress(rtp_receiver_handle_, audio_des.getAddress(), audio_des.getPort());
lib_player_.InitRTPReceiver(rtp_receiver_handle_);
if (startAudioPlay()) {
is_need_bye = false;
is_need_destory_rtp = false;
gb_broadcast_source_id_ = source_id_;
gb_broadcast_target_id_ = target_id_;
btnGB28181AudioBroadcast.setText("终止GB28181语音广播");
btnGB28181AudioBroadcast.setEnabled(true);
}
}
} else {
btnGB28181AudioBroadcast.setText("GB28181语音广播");
}
if (is_need_bye)
gb28181_agent_.byeAudioBroadcast(source_id_, target_id_);
}
if (is_need_destory_rtp)
destoryRTPReceiver();
}
private String source_id_;
private String target_id_;
private int status_code_;
private PlaySessionDescription session_description_;
public Runnable set(String source_id, String target_id, int status_code, PlaySessionDescription session_description) {
this.source_id_ = source_id;
this.target_id_ = target_id;
this.status_code_ = status_code;
this.session_description_ = session_description;
return this;
}
}.set(sourceID, targetID, statusCode, sessionDescription),0);
}startAudioPlay()初始化实例后，为了保证低延迟，拉流端设置0 buffer，处于调试方便，设置download speed回调2-5秒一次（可以看到是不是有音频数据过来），由于只需要播放音频，不需要视频，所以不要设置surface下去，然后设置拉流数据回调，需要注意的是，拉到的audio数据，不要转aac输出：
代码语言：javascript复制private boolean startAudioPlay() {
if (player_handle_ != 0 )
return false;
player_handle_ = lib_player_.SmartPlayerOpen(context_);
if (player_handle_ == 0)
return false;
lib_player_.SetSmartPlayerEventCallbackV2(player_handle_,new EventHandePlayerV2());
// 缓存大小可以调整
lib_player_.SmartPlayerSetBuffer(player_handle_, 0);
// lib_player_.SmartPlayerSetFastStartup(player_handle_, 0);
// set report download speed(默认2秒一次回调 用户可自行调整report间隔)
lib_player_.SmartPlayerSetReportDownloadSpeed(player_handle_, 1, 20);
lib_player_.SmartPlayerClearRtpReceivers(player_handle_);
lib_player_.SmartPlayerAddRtpReceiver(player_handle_, rtp_receiver_handle_);
lib_player_.SmartPlayerSetSurface(player_handle_, null);
// lib_player_.SmartPlayerSetRenderScaleMode(player_handle_, 1);
lib_player_.SmartPlayerSetAudioOutputType(player_handle_, 1);
lib_player_.SmartPlayerSetMute(player_handle_, 0);
lib_player_.SmartPlayerSetAudioVolume(player_handle_, 100);
lib_player_.SmartPlayerSetExternalAudioOutput(player_handle_, new PlayerExternalPCMOutput());
lib_player_.SmartPlayerSetUrl(player_handle_, "rtp://ntinternal/rtpreceiver/implemention0");
if (0 != lib_player_.SmartPlayerStartPlay(player_handle_)) {
lib_player_.SmartPlayerClose(player_handle_);
player_handle_ = 0;
Log.e(TAG, "start audio paly failed");
return false;
}
lib_player_.SmartPlayerSetAudioDataCallback(player_handle_, new PlayerAudioDataOutput());
lib_player_.SmartPlayerSetPullStreamAudioTranscodeAAC(player_handle_, 0);
if (0 ==lib_player_.SmartPlayerStartPullStream(player_handle_) ) {
// 启动定时器，长时间收不到音频数据，则停止播放，发送BYE
last_received_audio_data_time_.set(SystemClock.elapsedRealtime());
handler_.postDelayed(new AudioPlayerPCMTimer(player_handle_), AudioPlayerPCMTimer.INTERVAL_MS);
}
return true;
}调用StartPlay后，拿到的audio数据，塞到publisher端，做回音消除处理：
代码语言：javascript复制class PlayerExternalPCMOutput implements NTExternalAudioOutput {
private int buffer_size_ = 0;
private ByteBuffer pcm_buffer_ = null;
@Override
public ByteBuffer getPcmByteBuffer(int size) {
//Log.i("getPcmByteBuffer", "size: " size);
if(size < 1)
return null;
if(buffer_size_ != size) {
buffer_size_ = size;
pcm_buffer_ = ByteBuffer.allocateDirect(buffer_size_);
}
return pcm_buffer_;
}
public void onGetPcmFrame(int ret, int sampleRate, int channel, int sampleSize, int is_low_latency) {
/*Log.i("onGetPcmFrame", "ret: " ret ", sampleRate: " sampleRate ", channel: " channel ", sampleSize: " sampleSize
",is_low_latency:" is_low_latency " buffer_size：" buffer_size);*/
if (null == pcm_buffer_)
return;
pcm_buffer_.rewind();
if (ret == 0 && isGB28181StreamRunning && publisherHandle != 0 )
libPublisher.SmartPublisherOnFarEndPCMData(publisherHandle, pcm_buffer_, sampleRate, channel, sampleSize, is_low_latency);
}
}
private static int align(int d, int a) { return (d (a - 1)) & ~(a - 1); }
class PlayerAudioDataOutput implements NTAudioDataCallback {
private int buffer_size_ = 0;
private int param_info_size_ = 0;
private ByteBuffer 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 <= buffer_size_ && buffer_ != null )
return buffer_;
buffer_size_ = align(size 256, 16);
buffer_ = ByteBuffer.allocateDirect(buffer_size_);
// Log.i("getAudioByteBuffer", "size: " size " buffer_size:" audio_buffer_size);
return 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_ = align(size 32, 16);
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);
*/
last_received_audio_data_time_.set(SystemClock.elapsedRealtime());
}
}如果长时间收不到数据，主动断掉音频广播：
代码语言：javascript复制class AudioPlayerPCMTimer implements Runnable {
public static final int THRESHOLD_MS = 60*1000; // 暂时设置到1分钟
public static final int INTERVAL_MS = 10*1000; // 十秒一次, 太频繁影响主线程
public AudioPlayerPCMTimer(long handle) {
handle_ = handle;
}
@Override
public void run() {
if (0 == handle_)
return;
if (handle_ != player_handle_) {
Log.i(TAG, "AudioPlayerPCMTimer handle changed, will stop this timer, handle:" handle_ " new handle:" player_handle_);
return;
}
long last_update_time = last_received_audio_data_time_.get();
long cur_time = SystemClock.elapsedRealtime();
// Log.i(TAG, "AudioPlayerPCMTimer last_update_time:" last_update_time " cur_time:" cur_time);
if ( (last_update_time this.THRESHOLD_MS) > cur_time) {
// 继续定时器
handler_.postDelayed(new AudioPlayerPCMTimer(this.handle_), this.INTERVAL_MS);
// Log.i(TAG, "AudioPlayerPCMTimer running.");
}
else {
Log.i(TAG, "AudioPlayerPCMTimer,trigger threshold, bye audio, stop player.");
if (gb_broadcast_source_id_ != null && gb_broadcast_target_id_ != null) {
if (gb28181_agent_ != null)
gb28181_agent_.byeAudioBroadcast(gb_broadcast_source_id_, gb_broadcast_target_id_);
}
gb_broadcast_source_id_ = null;
gb_broadcast_target_id_ = null;
stopAudioPlayer();
destoryRTPReceiver();
btnGB28181AudioBroadcast.setText("GB28181语音广播");
btnGB28181AudioBroadcast.setEnabled(false);
}
}
private long handle_;
}停止广播数据播放：
代码语言：javascript复制private void stopAudioPlayer() {
if (player_handle_ != 0 ) {
lib_player_.SmartPlayerStopPullStream(player_handle_);
lib_player_.SmartPlayerStopPlay(player_handle_);
lib_player_.SmartPlayerClose(player_handle_);
player_handle_ = 0;
}
}销毁RTPReceiver：
代码语言：javascript复制private void destoryRTPReceiver() {
if (rtp_receiver_handle_ != 0) {
lib_player_.UnInitRTPReceiver(rtp_receiver_handle_);
lib_player_.DestoryRTPReceiverSession(rtp_receiver_handle_);
lib_player_.DestoryRTPReceiver(rtp_receiver_handle_);
rtp_receiver_handle_ = 0;
}
}以上是针对GB28181平台端音频广播播放的一点说明，感兴趣的开发者，可以酌情参考，也可以和我探讨Android平台GB28181接入模块的测试。
