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c#视频监控系列（9）服务器端—数据捕获抓图加录像
前言
录像功能是监控系统中最重要的功能之一，除了本文的功能实现外，还需要你自己考虑合适的存储策略：存储大小、时间段、存储盘符等。
正文
一、抓图
这个功能没有在VC++服务器端找到对应的代码，但是GOOGLE到了一段CSDN求助的代码：
int ret=GetJpegImage(aa,bb,cc,dd);
if(ret==0)
{
CString str;
str.Format("ch%02d_%s.jpg",iLastSelect,csStartTime);
FILE *pFile=fopen(str.GetBuffer(0),"wb");//Buffer应该是个缓冲区
if(pFile)
{
fwrite(bb,cc,1,pFile); //存储图像
fclose(pFile);
另外一段代码：http://topic.csdn.net/t/20060721/09/4894821.html
C#:
byte[] imageBuf = new byte[704*576*2];
int size = 704*576*2;
HikVisionSDK.GetJpegImage(ChannelHandle, imageBuf, out size, 100);
using (MemoryStream ms = new MemoryStream(imageBuf))
{
Image image = Image.FromStream(ms, true);
image.Save("C:1.jpg");
}
注意GetJpegImage的参数说明！！并且请注意，由于这个示例，发现前面的(GetJpegImage/GetOriginalImage)API错误了，请你及时更新！！
public static extern int GetOriginalImage(IntPtr hChannelHandle, byte[] ImageBuf, out int Size);
public static extern int GetJpegImage(IntPtr hChannelHandle, byte[] ImageBuf, out int Size, uint nQuality);
保存为bmp的方法请自行尝试，应该是差不多的: )
二、录像
关于录像的文件总共有三个部分，分别是文件头、数据流和文件尾，这里先给出代码，然后再进行说明。
VC++:
CHKVisionDlg::OnStart()
for(int i = 0; i < GetTotalDSPs(); i++){
m_bDspPreset[i]=TRUE;
if(m_bDspPreset[i]){
char fileName[256];
sprintf(fileName, "d:stream%d_%d.264", i, gFileNum++/GetTotalDSPs());
gFileHandle[i] = _open(fileName, _O_CREAT | _O_BINARY | _O_WRONLY| _O_TRUNC, _S_IREAD | _S_IWRITE);
if(gFileHandle[i] == -1){
TRACE("channel %d file open errorn,i");
return;
}
gChannelFrames[i] = 0;
gChannelTotalLength[i] = 0;
gChannelFramesLost[i] = 0;
gChannelOverflow[i] = 0;
gCurrentFileLen[i] = 0;
_write(gFileHandle[i], FileHeader[i], FileHeaderLen);
// could not be start again untill stopped first
//m_bDspPreset[i] = FALSE;
gCaptureStartedNum++;
// let the threads have chance to run
//Sleep(500);
}else
gFileHandle[i] = -1;
}
StreamDirectReadCallback
int __cdecl StreamDirectReadCallback(ULONG channelNum,void *DataBuf,DWORD Length,int frameType,void *context)
{
//CHKVisionDlg * lpDlg = (CHKVisionDlg*)context;
//return lpDlg->ProcCallBack(channelNum, DataBuf, Length, frameType);
int i,status=0;
CString ctip;
int nframetype =0;
// if cap images we need clean the queue here
// if (!bCapture)
// return 0;
// no errors
if(frameType > 0) {
if(frameType == PktSysHeader){
// store the file header
memcpy(FileHeader[channelNum], DataBuf, Length);
FileHeaderLen = Length;
TRACE("channel %d get the file header !n",channelNum);
}
if(frameType == PktIFrames || frameType ==PktSubIFrames){
status = 1;
}
else{
status = 0;
}
if(frameType == PktMotionDetection){
// m_VideoWin.DrawVect(channelNum, (char *)DataBuf, Length);
return 0;
}
if(frameType == PktOrigImage){
return 0;
}
}
if(Length == 0){
TRACE("no data ?n");
return 0;
}
// if(frameType == PktIFrames){
// int iii=1;
// }
ULONG currentTime = timeGetTime();
gChannelTotalLength[channelNum] += Length;
gCurrentFileLen[channelNum] += Length;
if(currentTime > StartTime+1000){
CString str,str2;
str.Format("%d", (gChannelTotalLength[dcurrentwin] *8/(currentTime - StartTime)));
for(i=0;i<g_nChannelTotal;i++)
gChannelTotalLength[i] = 0;
StartTime= currentTime;
CHKVisionDlg *pMain = (CHKVisionDlg *)AfxGetMainWnd();
pMain->GetDlgItem(IDC_BPS)->SetWindowText((LPCTSTR)str);
}
// if (m_sframe && channelNum ==0)
// {
// if((frameType == PktSFrames && nframetype ==4 )||(frameType == PktSysHeader))
// {
// MP4_ServerWriteData(channelNum,(unsigned char *)DataBuf, Length,frameType,status);
// }
// }
// MP4_ServerWriteData(channelNum,(unsigned char *)DataBuf, Length,frameType,status);
if(frameType ==PktAudioFrames)
{
_write(gFileHandleQcif[channelNum],DataBuf,Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,1);
_write(gFileHandle[channelNum], DataBuf, Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,0);
}else if (frameType ==PktSubIFrames || frameType ==PktSubPFrames || frameType == PktSubBBPFrames || frameType == PktSubSysHeader)
{
_write(gFileHandleQcif[channelNum],DataBuf,Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,1);
}else
{
//_write(gFileHandle[channelNum], DataBuf, Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,0);
}
return 0;
}
CHKVisionDlg::OnStop()
for(int i = 0; i < GetTotalDSPs(); i++){
if(m_bDspPreset[i]){
ASSERT(gFileHandle[i] != -1);
// StopVideoCapture(ChannelHandle[i]);
//lseek(gFileHandle[i], 0, SEEK_SET);
//FRAMES_STATISTICS fs;
//GetFramesStatistics(ChannelHandle[i], &fs);
//ULONG frames = fs.AudioFrames + fs.VideoFrames;
//TRACE("channel %i has %x frames writtenn", i, frames);
#define END_CODE 0x00000002
ULONG endCode = END_CODE;
_write(gFileHandle[i], &endCode, sizeof(ULONG));
_close(gFileHandle[i]);
///add v34
if (bEncodeCifAndQcif[i])
_close(gFileHandleQcif[i]);
gCaptureStartedNum--;
}
}
代码说明：
1. 从StartCap和StopCap的按钮事件可以看得出主要实现写文件头和文件尾的功能，注意_write函数。
2. 而上一章我们讲到了回调函数StreamDirectReadCallback，主要是将数据写到内存中，从代码能看出回调中是边写内存边写文件的代码，而且输出就是.264文件。由于回调从启动开始(允许被客户端访问)，就一直不停的在调用这个回调，根据断点调试可以看得出当frameType == PktSysHeader时表示的就是文件头，并且只执行一次，这样在点击StartCap按钮时就直接将这个保存的文件头的数据写入文件了，用UE打开.264的文件可以发现前几个字符总是以4HKH开头的文件。
3. 注意gFileHandle是一个文件指针数组，文件被打开后回调中就一直往这个文件指针写数据！！
C#:
//用于存放头文件
byte[] FileHeader;
//文件头长度
int FileHeaderLen;
//是否开始捕获文件 0 未启用 1 启用
volatile int CaptureState;
/// <summary>
/// 开始录像
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnStart_Click(object sender, EventArgs e)
{
//写入头文件
using (FileStream fs = new FileStream("C:hik.264", FileMode.Create))
{
BinaryWriter bw = new BinaryWriter(fs);
bw.Write(FileHeader);
bw.Flush();
bw.Close();
}
CaptureState = 1;
}
uint endCode = 0x00000002;
/// <summary>
/// 停止录像
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnStop_Click(object sender, EventArgs e)
{
CaptureState = 0;
using (FileStream fs = new FileStream("C:hik.264", FileMode.Append))
{
BinaryWriter bw = new BinaryWriter(fs);
bw.Write(endCode);
bw.Close();
}
}
public int STREAM_DIRECT_READ_CALLBACK1(int channelNum, IntPtr DataBuf, int Length, FrameType_t frameType, IntPtr context)
{
//int status = 0;
//HikServer.MP4_ServerWriteDataEx(channelNum, DataBuf, Length, (int)frameType, status, 0);
//return 0;
int status = 0;
if (frameType > 0)
{
if (frameType == FrameType_t.PktSysHeader)
{
FileHeader = new byte[Length];
Marshal.Copy(DataBuf, FileHeader, 0, Length);
FileHeaderLen = Length;
}
if (frameType == FrameType_t.PktIFrames || frameType == FrameType_t.PktSubIFrames)
status = 1;
else
status = 0;
if (frameType == FrameType_t.PktMotionDetection || frameType == FrameType_t.PktOrigImage)
return 0;
}
if (Length == 0)
{
//TRACE("no data ?n");
return 0;
}
if (frameType == FrameType_t.PktAudioFrames)
{
WriterVideoCapture(Length, DataBuf);
//写文件
// _write(gFileHandleQcif[channelNum],DataBuf,Length);
//HikServer.MP4_ServerWriteDataEx(channelNum, DataBuf, Length, (int)frameType, status, 1);
// _write(gFileHandle[channelNum], DataBuf, Length);
HikServer.MP4_ServerWriteDataEx(channelNum, DataBuf, Length, (int)frameType, status, 0);
}
else if (frameType == FrameType_t.PktSubIFrames || frameType == FrameType_t.PktSubPFrames || frameType == FrameType_t.PktSubBBPFrames || frameType == FrameType_t.PktSubSysHeader)
{
// _write(gFileHandleQcif[channelNum],DataBuf,Length);
HikServer.MP4_ServerWriteDataEx(channelNum, DataBuf, Length, (int)frameType, status, 1);
}
else
{
WriterVideoCapture(Length, DataBuf);
HikServer.MP4_ServerWriteDataEx(channelNum, DataBuf, Length, (int)frameType, status, 0);
}
return 0;
}
/// <summary>
/// 将数据流写入视频文件
/// </summary>
/// <param name="length"></param>
/// <param name="dataBuf"></param>
private void WriterVideoCapture(int length, IntPtr dataBuf)
{
if (CaptureState == 1)
{
using (FileStream fs = new FileStream("C:hik.264", FileMode.Append))
{
BinaryWriter bw = new BinaryWriter(fs);
byte[] byteBuf = new byte[length];
Marshal.Copy(dataBuf, byteBuf, 0, length);
bw.Write(byteBuf);
bw.Flush();
bw.Close();
}
}
}
代码说明：
1. 回调函数STREAM_DIRECT_READ_CALLBACK1是在上篇文章的基础上修改的，也主要是参照的VC++的源代码改写的。
2. CaptureState变量主要用于STREAM_DIRECT_READ_CALLBACK1中控制是否写文件。
3. btnStart_Click与btnStop_Click分别代表界面上的开始录像和停止录像按钮。
4. 注意写文件的方式，开始录像用FileMode.Create，持续写入用FileMode.Append。
补充：
1. 录像的时候务必考虑单录像文件的大小以及磁盘空间不够的问题，最好还能考虑下分时段监控等。
2. 注意保存文件头的变量FileHeader，如果分文件连续保存的话有可能出现第一个文件能播放，后面的都不能播放了，可能是文件头变量的数据类型问题，你可以换byte[] -> IntPtr保存试试看。
3. 自带的示例里面有播放器极其源码，打开播放器，直接将.264文件拖拽到里面就可以播放了；如果报错那么说明你的录像有问题！！
结束
虽然代码都给出来了，但是里面整个过程还是需要理解的，一定要配合VC++自带的例子进行调试编写。
public static extern int GetOriginalImage(IntPtr hChannelHandle, byte[] ImageBuf, out int Size);
public static extern int GetJpegImage(IntPtr hChannelHandle, byte[] ImageBuf, out int Size, uint nQuality);
保存为bmp的方法请自行尝试，应该是差不多的: )
二、录像
关于录像的文件总共有三个部分，分别是文件头、数据流和文件尾，这里先给出代码，然后再进行说明。
VC++:
CHKVisionDlg::OnStart()
for(int i = 0; i < GetTotalDSPs(); i++){
m_bDspPreset[i]=TRUE;
if(m_bDspPreset[i]){
char fileName[256];
sprintf(fileName, "d:stream%d_%d.264", i, gFileNum++/GetTotalDSPs());
gFileHandle[i] = _open(fileName, _O_CREAT | _O_BINARY | _O_WRONLY| _O_TRUNC, _S_IREAD | _S_IWRITE);
if(gFileHandle[i] == -1){
TRACE("channel %d file open errorn,i");
return;
}
gChannelFrames[i] = 0;
gChannelTotalLength[i] = 0;
gChannelFramesLost[i] = 0;
gChannelOverflow[i] = 0;
gCurrentFileLen[i] = 0;
_write(gFileHandle[i], FileHeader[i], FileHeaderLen);
// could not be start again untill stopped first
//m_bDspPreset[i] = FALSE;
gCaptureStartedNum++;
// let the threads have chance to run
//Sleep(500);
}else
gFileHandle[i] = -1;
}
StreamDirectReadCallback
int __cdecl StreamDirectReadCallback(ULONG channelNum,void *DataBuf,DWORD Length,int frameType,void *context)
{
//CHKVisionDlg * lpDlg = (CHKVisionDlg*)context;
//return lpDlg->ProcCallBack(channelNum, DataBuf, Length, frameType);
int i,status=0;
CString ctip;
int nframetype =0;
// if cap images we need clean the queue here
// if (!bCapture)
// return 0;
// no errors
if(frameType > 0) {
if(frameType == PktSysHeader){
// store the file header
memcpy(FileHeader[channelNum], DataBuf, Length);
FileHeaderLen = Length;
TRACE("channel %d get the file header !n",channelNum);
}
if(frameType == PktIFrames || frameType ==PktSubIFrames){
status = 1;
}
else{
status = 0;
}
if(frameType == PktMotionDetection){
// m_VideoWin.DrawVect(channelNum, (char *)DataBuf, Length);
return 0;
}
if(frameType == PktOrigImage){
return 0;
}
}
if(Length == 0){
TRACE("no data ?n");
return 0;
}
// if(frameType == PktIFrames){
// int iii=1;
// }
ULONG currentTime = timeGetTime();
gChannelTotalLength[channelNum] += Length;
gCurrentFileLen[channelNum] += Length;
if(currentTime > StartTime+1000){
CString str,str2;
str.Format("%d", (gChannelTotalLength[dcurrentwin] *8/(currentTime - StartTime)));
for(i=0;i<g_nChannelTotal;i++)
gChannelTotalLength[i] = 0;
StartTime= currentTime;
CHKVisionDlg *pMain = (CHKVisionDlg *)AfxGetMainWnd();
pMain->GetDlgItem(IDC_BPS)->SetWindowText((LPCTSTR)str);
}
// if (m_sframe && channelNum ==0)
// {
// if((frameType == PktSFrames && nframetype ==4 )||(frameType == PktSysHeader))
// {
// MP4_ServerWriteData(channelNum,(unsigned char *)DataBuf, Length,frameType,status);
// }
// }
// MP4_ServerWriteData(channelNum,(unsigned char *)DataBuf, Length,frameType,status);
if(frameType ==PktAudioFrames)
{
_write(gFileHandleQcif[channelNum],DataBuf,Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,1);
_write(gFileHandle[channelNum], DataBuf, Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,0);
}else if (frameType ==PktSubIFrames || frameType ==PktSubPFrames || frameType == PktSubBBPFrames || frameType == PktSubSysHeader)
{
_write(gFileHandleQcif[channelNum],DataBuf,Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,1);
}else
{
//_write(gFileHandle[channelNum], DataBuf, Length);
MP4_ServerWriteDataEx(channelNum,(unsigned char *)DataBuf, Length,frameType,status,0);
}
return 0;
}
CHKVisionDlg::OnStop()
for(int i = 0; i < GetTotalDSPs(); i++){
if(m_bDspPreset[i]){
ASSERT(gFileHandle[i] != -1);
// StopVideoCapture(ChannelHandle[i]);
//lseek(gFileHandle[i], 0, SEEK_SET);
//FRAMES_STATISTICS fs;
//GetFramesStatistics(ChannelHandle[i], &fs);
//ULONG frames = fs.AudioFrames + fs.VideoFrames;
//TRACE("channel %i has %x frames writtenn", i, frames);
#define END_CODE 0x00000002
ULONG endCode = END_CODE;
_write(gFileHandle[i], &endCode, sizeof(ULONG));
_close(gFileHandle[i]);
///add v34
if (bEncodeCifAndQcif[i])
_close(gFileHandleQcif[i]);
gCaptureStartedNum--;
}
}
