技术背景
我们在设计Android平台GB28181设备接入模块的时候，有这样的场景诉求，一个设备可能需要多个通道，常见的场景，比如车载终端，一台设备，可能需要接入多个摄像头，那么这台车载终端设备可以作为主设备，然后，主设备下，配置多个通道，听起来是不是有点儿类似于DVR或NVR？
技术实现
这里，我们说下，我们当时做这块，是怎么设计的，首先，在InitGB28181Agent的时候，添加设备通道，具体代码如下：
java
private boolean initGB28181Agent() {
if ( gb28181_agent_ != null )
return true;
getLocation(context_);
String local_ip_addr = IPAddrUtils.getIpAddress(context_);
Log.i(TAG, "[daniusdk.com]initGB28181Agent local ip addr: " + local_ip_addr);
if ( local_ip_addr == null || local_ip_addr.isEmpty() ) {
Log.e(TAG, "[daniusdk.com]initGB28181Agent local ip is empty");
return false;
}
gb28181_agent_ = GBSIPAgentFactory.getInstance().create();
if ( gb28181_agent_ == null ) {
Log.e(TAG, "[daniusdk.com]initGB28181Agent create agent failed");
return false;
}
gb28181_agent_.addListener(this);
gb28181_agent_.addPlayListener(this);
gb28181_agent_.addAudioBroadcastListener(this);
gb28181_agent_.addDeviceControlListener(this);
gb28181_agent_.addQueryCommandListener(this);
// 必填信息
gb28181_agent_.setLocalAddress(local_ip_addr);
gb28181_agent_.setServerParameter(gb28181_sip_server_addr_, gb28181_sip_server_port_, gb28181_sip_server_id_, gb28181_sip_domain_);
gb28181_agent_.setUserInfo(gb28181_sip_username_, gb28181_sip_password_);
//gb28181_agent_.setUserInfo(gb28181_sip_username_, gb28181_sip_username_, gb28181_sip_password_);
// 可选参数
gb28181_agent_.setUserAgent(gb28181_sip_user_agent_filed_);
gb28181_agent_.setTransportProtocol(gb28181_sip_trans_protocol_==0?"UDP":"TCP");
// GB28181配置
gb28181_agent_.config(gb28181_reg_expired_, gb28181_heartbeat_interval_, gb28181_heartbeat_count_);
com.gb.ntsignalling.Device gb_device = new com.gb.ntsignalling.Device("34020000001380000001", "安卓测试设备", Build.MANUFACTURER, Build.MODEL,
"宇宙","火星1","火星", true);
if (mLongitude != null && mLatitude != null) {
com.gb.ntsignalling.DevicePosition device_pos = new com.gb.ntsignalling.DevicePosition();
device_pos.setTime(mLocationTime);
device_pos.setLongitude(mLongitude);
device_pos.setLatitude(mLatitude);
gb_device.setPosition(device_pos);
gb_device.setSupportMobilePosition(true); // 设置支持移动位置上报
}
gb28181_agent_.addDevice(gb_device);
com.gb28181.ntsignalling.Device gb_device1 = new com.gb28181.ntsignalling.Device("34020000001380000002", "安卓测试设备2", Build.MANUFACTURER, Build.MODEL,
"宇宙","火星1","火星", true);
if (mLongitude != null && mLatitude != null) {
com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();
device_pos.setTime(mLocationTime);
device_pos.setLongitude(mLongitude);
device_pos.setLatitude(mLatitude);
gb_device1.setPosition(device_pos);
gb_device1.setSupportMobilePosition(true);
}
gb28181_agent_.addDevice(gb_device1);
if (!gb28181_agent_.createSipStack()) {
gb28181_agent_ = null;
Log.e(TAG, "[daniusdk.com]initGB28181Agent gb28181_agent_.createSipStack failed.");
return false;
}
boolean is_bind_local_port_ok = false;
// 最多尝试5000个端口
int try_end_port = gb28181_sip_local_port_base_ + 5000;
try_end_port = try_end_port > 65536 ?65536: try_end_port;
for (int i = gb28181_sip_local_port_base_; i < try_end_port; ++i) {
if (gb28181_agent_.bindLocalPort(i)) {
is_bind_local_port_ok = true;
break;
}
}
if (!is_bind_local_port_ok) {
gb28181_agent_.releaseSipStack();
gb28181_agent_ = null;
Log.e(TAG, "[daniusdk.com]initGB28181Agent gb28181_agent_.bindLocalPort failed.");
return false;
}
if (!gb28181_agent_.initialize()) {
gb28181_agent_.unBindLocalPort();
gb28181_agent_.releaseSipStack();
gb28181_agent_ = null;
Log.e(TAG, "[daniusdk.com]initGB28181Agent gb28181_agent_.initialize failed.");
return false;
}
return true;
}可以看到，我们调用addDevice(gb_device);添加了两个通道，具体如下：
java
com.gb.ntsignalling.Device gb_device = new com.gb.ntsignalling.Device("34020000001380000001", "安卓测试设备", Build.MANUFACTURER, Build.MODEL,
"宇宙","火星1","火星", true);
if (mLongitude != null && mLatitude != null) {
com.gb.ntsignalling.DevicePosition device_pos = new com.gb.ntsignalling.DevicePosition();
device_pos.setTime(mLocationTime);
device_pos.setLongitude(mLongitude);
device_pos.setLatitude(mLatitude);
gb_device.setPosition(device_pos);
gb_device.setSupportMobilePosition(true); // 设置支持移动位置上报
}
gb28181_agent_.addDevice(gb_device);
com.gb28181.ntsignalling.Device gb_device1 = new com.gb28181.ntsignalling.Device("34020000001380000002", "安卓测试设备2", Build.MANUFACTURER, Build.MODEL,
"宇宙","火星1","火星", true);
if (mLongitude != null && mLatitude != null) {
com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();
device_pos.setTime(mLocationTime);
device_pos.setLongitude(mLongitude);
device_pos.setLatitude(mLatitude);
gb_device1.setPosition(device_pos);
gb_device1.setSupportMobilePosition(true);
}
gb28181_agent_.addDevice(gb_device1);一台设备，分别对应了两个device。
invite请求过来的时候，我们会把deviceid回上来，上层可以针对不同的deviceid做预览处理：
java
@Override
public void ntsOnInvitePlay(String deviceId, SessionDescription session_des) {
handler_.postDelayed(new Runnable() {
@Override
public void run() {
// 先振铃响应下
gb28181_agent_.respondPlayInvite(180, device_id_);
MediaSessionDescription video_des = null;
SDPRtpMapAttribute ps_rtpmap_attr = null;
// 28181 视频使用PS打包
Vector<MediaSessionDescription> video_des_list = session_des_.getVideoPSDescriptions();
if (video_des_list != null && !video_des_list.isEmpty()) {
for(MediaSessionDescription m : video_des_list) {
if (m != null && m.isValidAddressType() && m.isHasAddress() ) {
video_des = m;
ps_rtpmap_attr = video_des.getPSRtpMapAttribute();
break;
}
}
}
if (null == video_des) {
gb28181_agent_.respondPlayInvite(488, device_id_);
Log.i(TAG, "ntsOnInvitePlay get video description is null, response 488, device_id:" + device_id_);
return;
}
if (null == ps_rtpmap_attr) {
gb28181_agent_.respondPlayInvite(488, device_id_);
Log.i(TAG, "ntsOnInvitePlay get ps rtp map attribute is null, response 488, device_id:" + device_id_);
return;
}
Log.i(TAG,"ntsOnInvitePlay, device_id:" +device_id_+", is_tcp:" + video_des.isRTPOverTCP()
+ " rtp_port:" + video_des.getPort() + " ss rc:" + video_des.getSS-RC()
+ " address_type:" + video_des.getAddressType() + " address:" + video_des.getAddress());
long rtp_sender_handle = libPublisher.CreateRTPSender(0);
if ( rtp_sender_handle == 0 ) {
gb28181_agent_.respondPlayInvite(488, device_id_);
Log.i(TAG, "ntsOnInvitePlay CreateRTPSender failed, response 488, device_id:" + device_id_);
return;
}
gb28181_rtp_payload_type_ = ps_rtpmap_attr.getPayloadType();
gb28181_rtp_encoding_name_ = ps_rtpmap_attr.getEncodingName();
libPublisher.SetRTPSenderTransportProtocol(rtp_sender_handle, video_des.isRTPOverUDP()?0:1);
libPublisher.SetRTPSenderIPAddressType(rtp_sender_handle, video_des.isIPv4()?0:1);
libPublisher.SetRTPSenderLocalPort(rtp_sender_handle, 0);
libPublisher.SetRTPSenderSS-RC(rtp_sender_handle, video_des.getSS-RC());
libPublisher.SetRTPSenderSocketSendBuffer(rtp_sender_handle, 2*1024*1024); // 设置到2M
libPublisher.SetRTPSenderClockRate(rtp_sender_handle, ps_rtpmap_attr.getClockRate());
libPublisher.SetRTPSenderDestination(rtp_sender_handle, video_des.getAddress(), video_des.getPort());
if ( libPublisher.InitRTPSender(rtp_sender_handle) != 0 ) {
gb28181_agent_.respondPlayInvite(488, device_id_);
libPublisher.DestoryRTPSender(rtp_sender_handle);
return;
}
int local_port = libPublisher.GetRTPSenderLocalPort(rtp_sender_handle);
if (local_port == 0) {
gb28181_agent_.respondPlayInvite(488, device_id_);
libPublisher.DestoryRTPSender(rtp_sender_handle);
return;
}
Log.i(TAG,"get local_port:" + local_port);
String local_ip_addr = IPAddrUtils.getIpAddress(context_);
MediaSessionDescription local_video_des = new MediaSessionDescription(video_des.getType());
local_video_des.addFormat(String.valueOf(ps_rtpmap_attr.getPayloadType()));
local_video_des.addRtpMapAttribute(ps_rtpmap_attr);
local_video_des.setAddressType(video_des.getAddressType());
local_video_des.setAddress(local_ip_addr);
local_video_des.setPort(local_port);
local_video_des.setTransportProtocol(video_des.getTransportProtocol());
local_video_des.setSS-RC(video_des.getSS-RC());
if (!gb28181_agent_.respondPlayInviteOK(device_id_,local_video_des) ) {
libPublisher.DestoryRTPSender(rtp_sender_handle);
Log.e(TAG, "ntsOnInvitePlay call respondPlayInviteOK failed.");
return;
}
gb28181_rtp_sender_handle_ = rtp_sender_handle;
}
private String device_id_;
private SessionDescription session_des_;
public Runnable set(String device_id, SessionDescription session_des) {
this.device_id_ = device_id;
this.session_des_ = session_des;
return this;
}
}.set(deviceId, session_des),0);
}收到ACK后，也携带了deviceid作为区分：
java
@Override
public void ntsOnAckPlay(String deviceId) {
handler_.postDelayed(new Runnable() {
@Override
public void run() {
Log.i(TAG,"ntsOnACKPlay, device_id:" +device_id_);
if (!isRTSPPublisherRunning && !isPushingRtmp && !isRecording) {
InitAndSetConfig();
}
libPublisher.SetGB28181RTPSender(publisherHandle, gb28181_rtp_sender_handle_, gb28181_rtp_payload_type_, gb28181_rtp_encoding_name_);
//libPublisher.SetGBTCPConnectTimeout(publisherHandle, 10*60*1000);
//libPublisher.SetGBInitialTCPReconnectInterval(publisherHandle, 1000);
//libPublisher.SetGBInitialTCPMaxReconnectAttempts(publisherHandle, 3);
int startRet = libPublisher.StartGB28181MediaStream(publisherHandle);
if (startRet != 0) {
if (!isRTSPPublisherRunning && !isPushingRtmp && !isRecording) {
if (publisherHandle != 0) {
long handle = publisherHandle;
publisherHandle = 0;
libPublisher.SmartPublisherClose(handle);
}
}
destoryRTPSender();
Log.e(TAG, "Failed to start GB28181 service..");
return;
}
if (!isRTSPPublisherRunning && !isPushingRtmp && !isRecording) {
CheckInitAudioRecorder();
}
startLayerPostThread();
isGB28181StreamRunning = true;
}
private String device_id_;
public Runnable set(String device_id) {
this.device_id_ = device_id;
return this;
}
}.set(deviceId),0);
}TerminatePlayer处理如下：
java
@Override
public void ntsOnTerminatePlay(String deviceId) {
handler_.postDelayed(new Runnable() {
@Override
public void run() {
Log.i(TAG, "ntsOnTerminatePlay, stop GB28181 media stream, deviceId=" + device_id_);
stopGB28181Stream();
destoryRTPSender();
}
private String device_id_;
public Runnable set(String device_id) {
this.device_id_ = device_id;
return this;
}
}.set(deviceId),0);
}这样每个deviceid对应一个实例，如果有多个摄像头的话，摄像头，可以按照deviceid来做区分，国标平台侧请求哪个deviceid的话，就启动这个deviceid对应的camera采集、编码和数据打包上传。