随着流媒体技术的迅速发展，H5流媒体播放器已成为现代网络视频播放的重要工具。其中，EasyPlayer.js播放器作为一款功能强大的H5播放器，凭借其全面的协议支持、多种解码方式以及跨平台兼容性，赢得了广泛的关注和应用。
那么想要实现播放器本地快照抓拍截图功能，应该如何操作呢？
实现步骤：
1、将解码后的帧进行格式转换（目标格式为RGB24）。
2、采用独立的线程进行截图处理。
3、截图可保存为BMP或JPG两种格式。
代码实现：
int Snapshot2File(RENDER_FORMAT renderFormat, SNAPSHOT_IMAGE_T *pSnapshot, char *pbuf)
{
PBYTE pDest = NULL, pDest16 = NULL;
INT nBpp;
DWORD dwW, dwH, dwWB;
int ret = 0;
int image_format = pSnapshot->imageFormat;
if (renderFormat == RENDER_FORMAT_YUY2) nBpp = 16;
else if (renderFormat == RENDER_FORMAT_UYVY) nBpp = 16;
else if (renderFormat == RENDER_FORMAT_X8R8G8B8) nBpp = 32; //ok
else if (renderFormat == RENDER_FORMAT_A8R8G8B8) nBpp = 32; //ok
else if (renderFormat == RENDER_FORMAT_RGB565) nBpp = 16; //ok
else if (renderFormat == RENDER_FORMAT_RGB555) nBpp = 16; //ok
else if (renderFormat == RENDER_FORMAT_RGB24_GDI) nBpp = 24;
else return -1; //格式错误
dwW = pSnapshot->width;
dwH = pSnapshot->height;
dwWB = _WIDTHBYTES( dwW * nBpp );
if (image_format == 0x00)
{
//BMP
int iFilenameLen = (int)strlen(pSnapshot->filename);
if ( (0 != memcmp(pSnapshot->filename+iFilenameLen-3, "bmp", 3)) &&
(0 != memcmp(pSnapshot->filename+iFilenameLen-3, "BMP", 3)) &&
(0 != memcmp(pSnapshot->filename+iFilenameLen-3, "Bmp", 3)) )
{
if (pSnapshot->filename[iFilenameLen-4] == '.')
{
for (int i=iFilenameLen-1; i>0; i--)
{
if (pSnapshot->filename[i] == '.')
{
pSnapshot->filename[i] = '\0';
break;
}
else
{
pSnapshot->filename[i] = '\0';
}
}
}
strcat(pSnapshot->filename, ".bmp");
}
HANDLE hFile = CreateFile( pSnapshot->filename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL );
if( hFile == INVALID_HANDLE_VALUE ) return E_HANDLE;
// SaveFile to BMP
BITMAPFILEHEADER bfh = {0};
bfh.bfType = 0x4D42;
bfh.bfSize = 0;
bfh.bfReserved1 = 0;
bfh.bfReserved2 = 0;
bfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
if( nBpp == 16 ) {
bfh.bfOffBits += sizeof(RGBQUAD) * 3;
}
else
if( nBpp == 24 ) {
bfh.bfOffBits += sizeof(RGBQUAD) * 1;
}
else
if( nBpp == 32 ) {
bfh.bfOffBits += sizeof(RGBQUAD) * 1;
}
DWORD dwWriteLength = sizeof(BITMAPFILEHEADER);
DWORD dwWrittenLength = 0;
WriteFile( hFile, (PVOID)&bfh, dwWriteLength, &dwWrittenLength, NULL );
BITMAPINFOHEADER bih = {0};
bih.biSize = sizeof(BITMAPINFOHEADER);
bih.biWidth = dwW;
bih.biHeight = -(INT)dwH;
bih.biPlanes = 1;
bih.biBitCount = nBpp;
bih.biCompression = (nBpp == 16) ? BI_BITFIELDS : BI_RGB;
bih.biSizeImage = dwWB * pSnapshot->height;
bih.biXPelsPerMeter = 0;
bih.biYPelsPerMeter = 0;
bih.biClrUsed = 0;
bih.biClrImportant = 0;
dwWriteLength = sizeof(BITMAPINFOHEADER);
WriteFile( hFile, (PVOID)&bih, dwWriteLength, &dwWrittenLength, NULL );
if( nBpp == 16 ) {
DWORD argbQuad[3] = {0};
if (renderFormat == RENDER_FORMAT_RGB565)
{
argbQuad[0] = 0x00F800; // Red mask
argbQuad[1] = 0x0007E0; // Green mask
argbQuad[2] = 0x00001F; // Blue mask
}
else
{
argbQuad[0] = 0x007C00; // Red mask
argbQuad[1] = 0x0003E0; // Green mask
argbQuad[2] = 0x00001F; // Blue mask
}
dwWriteLength = sizeof(argbQuad);
WriteFile( hFile, (PVOID)&argbQuad[0], dwWriteLength, &dwWrittenLength, NULL );
}
else
if( nBpp == 24 ) {
DWORD rgbQuad = 0;
dwWriteLength = sizeof(rgbQuad);
WriteFile( hFile, (PVOID)&rgbQuad, dwWriteLength, &dwWrittenLength, NULL );
}
else if( nBpp == 32 ) {
DWORD rgbQuad = 0;
dwWriteLength = sizeof(rgbQuad);
WriteFile( hFile, (PVOID)&rgbQuad, dwWriteLength, &dwWrittenLength, NULL );
}
dwWriteLength = dwWB * pSnapshot->height;
WriteFile( hFile, (PVOID)pbuf, dwWriteLength, &dwWrittenLength, NULL );
CloseHandle( hFile );
if (dwWrittenLength < 1)
{
DeleteFile(pSnapshot->filename);
}
}
else if (image_format == 0x01)
{
//JPG
int iFilenameLen = (int)strlen(pSnapshot->filename);
if ( (0 != memcmp(pSnapshot->filename+iFilenameLen-3, "jpg", 3)) &&
(0 != memcmp(pSnapshot->filename+iFilenameLen-3, "JPG", 3)) &&
(0 != memcmp(pSnapshot->filename+iFilenameLen-3, "Jpg", 3)) )
{
if (pSnapshot->filename[iFilenameLen-4] == '.')
{
for (int i=iFilenameLen-1; i>0; i--)
{
if (pSnapshot->filename[i] == '.')
{
pSnapshot->filename[i] = '\0';
break;
}
else
{
pSnapshot->filename[i] = '\0';
}
}
}
strcat(pSnapshot->filename, ".jpg");
}
BOOL bres = TRUE;
IJLERR jerr;
DWORD dibPadBytes;
JPEG_CORE_PROPERTIES jcprops;
__try
{
jerr = ijlInit(&jcprops);
if (IJL_OK != jerr)
{
bres = FALSE;
__leave;
}
dibPadBytes = IJL_DIB_PAD_BYTES(dwW, 3);
jcprops.DIBWidth = dwW;
jcprops.DIBHeight = dwH;
jcprops.DIBBytes = (unsigned char*)pbuf;//reinterpret_cast<BYTE *>(&pbi->bmiHeader) + sizeof(BITMAPINFOHEADER);
jcprops.DIBPadBytes = dibPadBytes;
jcprops.DIBChannels = 3;
jcprops.DIBColor = IJL_BGR;
jcprops.JPGFile = const_cast<LPSTR>(pSnapshot->filename);
jcprops.JPGWidth = dwW;
jcprops.JPGHeight = dwH;
jcprops.JPGChannels = 3;
jcprops.JPGColor = IJL_YCBCR;
jcprops.JPGSubsampling = IJL_411;
jcprops.jquality = 95;
jerr = ijlWrite(&jcprops, IJL_JFILE_WRITEWHOLEIMAGE);
if (IJL_OK != jerr)
{
if (IJL_FILE_ERROR == jerr)
{
}
ret = jerr;
bres = FALSE;
if (ret == -23)
{
DeleteFile(pSnapshot->filename);
}
}
}
__finally
{
ijlFree(&jcprops);
}
}
if (NULL != pDest)
{
delete []pDest;
pDest = NULL;
}
return ret;
}
EasyPlayer.js视频流媒体播放器不仅支持H.264与H.265视频编码格式，也能支持WebSocket-FLV、HTTP-FLV、HLS（m3u8）、WebRTC、ws-fmp4、http-fmp4等格式的视频流，并具备直播、点播、录像、快照截图、MP4播放、多屏播放、倍数播放、全屏播放等功能特性。
流媒体拥有广阔的应用前景，很多人对它的了解也在逐步深入。流媒体播放器负责解码和呈现内容，常见的播放器包括VLC和HTML5播放器等。流媒体技术的应用场景广泛，包括娱乐、教育、视频监控、企业培训等。
