基于安卓系统的执法记录仪、智能头盔等设备,设备端录像、录像查询以及录像文件下载是必不可少的功能, 使用GB28181协议下载安卓设备上的录像文件, 检索录像文件是第一步, 先查询再下载,这里记录下我实现视音频文件检索的一些细节问题.
检索请求和查询结果都使用SIP MESSAGE+MANSCDP协议.
信令流程:
1. 向安卓设备发送目录查询请求 MESSAGE消息,消息体中包含文件检索条件, 消息体类型为:Application/MANSCDP+xml
2. 安卓设备向检索方回复200OK, 无消息体.
3. 安卓根据查询条件执行查询,查询结果用MESSAGE消息发给检索方,消息体类型为:Application/MANSCDP+xml
4.检索方回复200OK, 无消息体.
查询条件的详细定义请参考GB28181标准,这里给出一个例子:
<?xml version="1.0" encoding="GB2312"?><Query><CmdType>RecordInfo</CmdType><SN>73</SN><DeviceID>64010000001310000003</DeviceID><StartTime>2023-08-23T06:07:29</StartTime><EndTime>2023-08-23T22:10:31</EndTime></Query>
查询开始时间是:2023-08-23 06:07:29, 结束时间: 2023-08-23 10:10:31, StartTime和EndTime类型是xs:dateTime, xs:dateTime 详细定义请参考W3C XML Schema Definition Language文档.
xs:dateTime非形式化定义:"YYYY-MM-DDThh:mm:ss", 在国内使用场景中可能不太在意时区问题, 如果遇到时区问题, xs:dateTime也支持时区信息, 例如: "2023-08-23T06:07:29Z" 表示UTC时间, "2023-08-23T06:07:29+08:00" 换算成北京时间是:"2023-08-23 14:07:29".
查询条件中的"StartTime"和"EndTime" 如何使用没找到详细的说明,我的代码实现是这样规定的,一:把这个时间范围定义为半闭半开区间,也就是: [StartTime, EndTime), 二. 查找文件时只判断录像文件的开始时间是否在[StartTime, EndTime)范围内,录像文件的结束时间不考虑.
查询结果的详细定义参考GB28181标准就好,下面给出一个有查询结果的例子和一个无查询结果的例子:
<!----查询结果分两次发送, 总共5条----->
<!---第一次发送3条--->
<?xml version="1.0" encoding="GB2312"?><Response><CmdType>RecordInfo</CmdType><SN>73</SN><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><SumNum>5</SumNum><RecordList Num="3"><Item><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><StartTime>2023-08-23T12:27:18</StartTime><EndTime>2023-08-23T12:27:21</EndTime><Secrecy>0</Secrecy></Item><Item><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><StartTime>2023-08-23T12:27:23</StartTime><EndTime>2023-08-23T12:27:26</EndTime><Secrecy>0</Secrecy></Item><Item><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><StartTime>2023-08-23T16:52:10</StartTime><EndTime>2023-08-23T16:53:01</EndTime><Secrecy>0</Secrecy></Item></RecordList></Response><!---第二次发送2条--->
<?xml version="1.0" encoding="GB2312"?><Response><CmdType>RecordInfo</CmdType><SN>73</SN><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><SumNum>5</SumNum><RecordList Num="2"><Item><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><StartTime>2023-08-23T17:21:18</StartTime><EndTime>2023-08-23T17:37:21</EndTime><Secrecy>0</Secrecy></Item><Item><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><StartTime>2023-08-23T18:15:22</StartTime><EndTime>2023-08-23T18:33:58</EndTime><Secrecy>0</Secrecy></Item></RecordList></Response><!----没有查询到文件的例子---><?xml version="1.0" encoding="GB2312"?><Response><CmdType>RecordInfo</CmdType><SN>73</SN><DeviceID>64010000001310000003</DeviceID><Name>anrdoid-dev-test</Name><SumNum>0</SumNum></Response>
查询结果的一些实现细节:
1. 如果没有查询到文件,响应中<SumNum>元素内容填充"0", 且不携带<RecordList>元素.
2. 根据RFC3428
The size of MESSAGE requests outside of a media session MUST NOT exceed 1300 bytes,
会话外的SIP MESSAGE请求大小不能超过1300个字节(1300个字节限制的是整体消息大小,不止是Body Length).
针对这个消息大小限制问题, GB28181附录给出两种解决方案:
方案一: 对多条查询结果进行拆分,确保每个MESSAGE消息大小不超过1300个字节,每个响应消息的SN要与查询请求的SN相同, 串行发送, 也就是上一次发送的MESSAGE收到200 OK响应后,再发下一批拆分的查询结果, 代码实现上要计算每个SIP消息大小,记录好状态,具体实现起来比较麻烦;
方案二: SIP消息使用TCP传输, 这个需要服务端和安卓设备都支持TCP传输,GB28181要求每条响应消息携带的文件记录数上限为10000条,实际代码实现中建议不要一次发送太多条记录, 要考虑XML解析性能问题,大XML解析挺慢的.
另外我建议文件记录中的可选元素场景中不需要的就不加, 尽可能减少XML大小,降低信令传输带宽.
我的接口定义和Demo代码:
/*
* Copyright (C) 1130758427@qq.com. All rights reserved.
*/package com.gb.ntsignalling;public interface GBSIPAgent {void addListener(GBSIPAgentListener listener);void addPlayListener(GBSIPAgentPlayListener playListener);void removePlayListener(GBSIPAgentPlayListener playListener);void addDownloadListener(GBSIPAgentDownloadListener downloadListener);void removeDownloadListener(GBSIPAgentDownloadListener removeListener);void addTalkListener(GBSIPAgentTalkListener talkListener);void removeTalkListener(GBSIPAgentTalkListener talkListener);void addAudioBroadcastListener(GBSIPAgentAudioBroadcastListener audioBroadcastListener);void addDeviceControlListener(GBSIPAgentDeviceControlListener deviceControlListener);void addQueryCommandListener(GBSIPAgentQueryCommandListener queryCommandListener);void addQueryRecordInfoListener(GBSIPAgentQueryRecordInfoListener queryRecordInfoListener);/*历史视音频文件检索应答*/boolean respondRecordInfoQueryCommand(String fromUserName, String fromUserNameAtDomain, String toUserName,String deviceName, RecordQueryInfo queryInfo,java.util.List<RecordFileInfo> recordList);
}package com.gb.ntsignalling;public interface GBSIPAgentQueryRecordInfoListener {void ntsOnQueryRecordInfoCommand(String fromUserName, String fromUserNameAtDomain,String toUserName,RecordQueryInfo recordQueryInfo);
}package com.gb.ntsignalling;public interface RecordQueryInfo {/**命令序列号(必选)*/String getSN();/** 目录设备/视频监控联网系统/区域编码(必选)*/String getDeviceID();/** 录像起始时间(必选)*/String getStartTime();/** 录像终止时间(必选)*/String getEndTime();/** 文件路径名 (可选)*/String getFilePath();/** 录像地址(可选 支持不完全查询)*/String getAddress();/** 保密属性(可选)缺省为0;0:不涉密,1:涉密*/String getSecrecy();/** 录像产生类型(可选)time或alarm 或 manual或all*/String getType();/** 录像触发者ID(可选)*/String getRecorderID();/**录像模糊查询属性(可选)缺省为0;0:不进行模糊查询,此时根据 SIP 消息中 To头域*URI中的ID值确定查询录像位置,若ID值为本域系统ID 则进行中心历史记录检索,若为前*端设备ID则进行前端设备历史记录检索;1:进行模糊查询,此时设备所在域应同时进行中心*检索和前端检索并将结果统一返回.*/String getIndistinctQuery();
}package com.gb.ntsignalling;public class RecordFileInfo {/* 设备/区域编码(必选) */private String mDeviceID;/* 设备/区域名称(必选) */private String mName;/*文件路径名 (可选)*/private String mFilePath;/*录像地址(可选)*/private String mAddress;/*录像开始时间(可选)*/private String mStartTime;/*录像结束时间(可选)*/private String mEndTime;/*保密属性(必选)缺省为0;0:不涉密,1:涉密*/private String mSecrecy = "0";/*录像产生类型(可选)time或alarm 或 manual*/private String mType;/*录像触发者ID(可选)*/private String mRecorderID;/*录像文件大小,单位:Byte(可选)*/private String mFileSize;public RecordFileInfo() { }public RecordFileInfo(String deviceID) {this.setDeviceID(deviceID);}public RecordFileInfo(String deviceID, String name) {this.setDeviceID(deviceID);this.setName(name);}public String getDeviceID() {return mDeviceID;}public void setDeviceID(String deviceID) {this.mDeviceID = deviceID;}public String getName() {return mName;}public void setName(String name) {this.mName = name;}public String getFilePath() {return mFilePath;}public void setFilePath(String filePath) {this.mFilePath = filePath;}public String getAddress() {return mAddress;}public void setAddress(String address) {this.mAddress = address;}public String getStartTime() {return mStartTime;}public void setStartTime(String startTime) {this.mStartTime = startTime;}public String getEndTime() {return mEndTime;}public void setEndTime(String endTime) {this.mEndTime = endTime;}public String getSecrecy() {return mSecrecy;}public void setSecrecy(String secrecy) {this.mSecrecy = secrecy;}public String getType() {return mType;}public void setType(String type) {this.mType = type;}public String getRecorderID() {return mRecorderID;}public void setRecorderID(String recorderID) {this.mRecorderID = recorderID;}public String getFileSize() {return mFileSize;}public void setFileSize(String fileSize) {this.mFileSize = fileSize;}
}package com.mydemo;import com.gb.ntsignalling.GBSIPAgentQueryRecordInfoListener;public class MyAndroidG8181DemoImpl implements GBSIPAgentQueryRecordInfoListener {private static class QueryRecordInfoTask extends RecordExecutorService.CancelableTask {@Overridepublic void run() {RecordBaseQuery base_query = new RecordBaseQuery(get_canceler(), rec_dir_);java.util.Date start_time_lower = base_query.parser_xml_date_time(record_query_info_.getStartTime());java.util.Date start_time_upper = base_query.parser_xml_date_time(record_query_info_.getEndTime());if (null == start_time_lower || null == start_time_upper) {Log.e(TAG, "start_time_lower:" + start_time_lower + " or start_time_upper:" + start_time_upper + " is null");return;}base_query.set_start_time_lower(start_time_lower);base_query.set_start_time_upper(start_time_upper);List<RecordFileDescription> file_list = base_query.execute();if (is_cancel())return;file_list = base_query.sort_by_start_time_asc(file_list);if (is_cancel())return;List<com.gb.ntsignalling.RecordFileInfo> list = base_query.to_record_file_info_list(file_list, record_query_info_.getDeviceID(), null);if (is_cancel())return;if (file_list != null) {for (RecordFileDescription i : file_list)Log.i(TAG, i.toString(base_query.get_print_begin_date_time_format(), base_query.get_print_end_date_time_format()));}if (is_cancel() ||null == handler_ || null == sip_agent_)return;Handler handler = handler_.get();GBSIPAgent sip_agent = sip_agent_.get();if (null == handler || null == sip_agent)return;handler.post(new Runnable() {@Overridepublic void run() {if (null == this.sip_agent_)return;GBSIPAgent sip_agent = this.sip_agent_.get();if (null == sip_agent)return;if (this.canceler_ != null && this.canceler_.get())return;String device_name = null;sip_agent.respondRecordInfoQueryCommand(from_user_name_, from_user_name_at_domain_,to_user_name_, device_name, this.record_query_info_, this.record_list_);}private WeakReference<GBSIPAgent> sip_agent_;private AtomicBoolean canceler_;private String from_user_name_;private String from_user_name_at_domain_;private String to_user_name_;private RecordQueryInfo record_query_info_;private List<RecordFileInfo> record_list_;public Runnable set(GBSIPAgent sip_agent, AtomicBoolean canceler, String from_user_name, String from_user_name_at_domain, String to_user_name,RecordQueryInfo record_query_info, List<RecordFileInfo> record_list) {this.sip_agent_ = new WeakReference<>(sip_agent);this.canceler_ = canceler;this.from_user_name_ = from_user_name;this.from_user_name_at_domain_ = from_user_name_at_domain;this.to_user_name_ = to_user_name;this.record_query_info_ = record_query_info;this.record_list_ = record_list;return this;}}.set(sip_agent, get_canceler(), this.from_user_name_, this.from_user_name_at_domain_, this.to_user_name_,this.record_query_info_, list));}public QueryRecordInfoTask set(Handler handler, GBSIPAgent sip_agent, String rec_dir,String from_user_name, String from_user_name_at_domain,String to_user_name, RecordQueryInfo query_info) {this.handler_ = new WeakReference<>(handler);this.sip_agent_ = new WeakReference<>(sip_agent);this.rec_dir_ = rec_dir;this.from_user_name_ = from_user_name;this.from_user_name_at_domain_ = from_user_name_at_domain;this.to_user_name_ = to_user_name;this.record_query_info_ = query_info;return this;}private WeakReference<Handler> handler_;private WeakReference<GBSIPAgent> sip_agent_;private String rec_dir_;private String from_user_name_;private String from_user_name_at_domain_;private String to_user_name_;private RecordQueryInfo record_query_info_;}@Overridepublic void ntsOnQueryRecordInfoCommand(String fromUserName, String fromUserNameAtDomain, final String toUserName,RecordQueryInfo recordQueryInfo) {handler_.post(new Runnable() {@Overridepublic void run() {Log.i(TAG, "ntsOnQueryRecordInfoCommand from_user_name:" + from_user_name_ + ", to_user_name:" + to_user_name_+ ", sn:" + record_query_info_.getSN() + ", device_id:" + record_query_info_.getDeviceID() +", start_time:" + record_query_info_.getStartTime() + ", end_time:" + record_query_info_.getEndTime());QueryRecordInfoTask query_task = new QueryRecordInfoTask();query_task.set(handler_, gb28181_agent_, recDir, from_user_name_, from_user_name_at_domain_, to_user_name_, record_query_info_);if (!record_executor_.submit(query_task))Log.e(TAG, "ntsOnQueryRecordInfoCommand call record_executor_.submit failed");}private String from_user_name_;private String from_user_name_at_domain_;private String to_user_name_;private RecordQueryInfo record_query_info_;public Runnable set(String from_user_name, String from_user_name_at_domain, String to_user_name, RecordQueryInfo record_query_info) {this.from_user_name_ = from_user_name;this.from_user_name_at_domain_ = from_user_name_at_domain;this.to_user_name_ = to_user_name;this.record_query_info_ = record_query_info;return this;}}.set(fromUserName, fromUserNameAtDomain, toUserName, recordQueryInfo));}
}
整个历史视音频文件检索的实现代码较多,这里为了方便说明信令流程和关键细节,只给出接口定义和基本Demo, 如有不清楚的地方请联系qq: 1130758427, 从协议到一个可靠稳定的代码实现,需要花不少精力和时间.