怎么从视频文件中抽取每一帧的图像数据？用控件不用控件都可以，我现在用DSPack不好实现啊。

Question

我问的问题以前有人问过,但没有答案就结帖了
以下是原帖地址:
http://topic.csdn.net/t/20051127/15/4421192.html我也是想尽快截取每一帧的数据,
我没有分,不过如果能完成,我会帖出源码以便于更多人可以分享到此答案,无论是大家指教的还是自己研究出来的
谢谢

Answer 1

线索
在directshow有一对象,IMediaDet,可以读取视频某一秒的图片
但我希望能够用SampleGrabber按视频顺序获得所有帧,
SampleGrabber or the Null Renderer,应该可以实现以下为IMediaDet获得某帧图片的源码unit VideoFrameGrabber;interfaceuses
  Windows, SysUtils, ExtCtrls;type
  TVideoFrameGrabber = class(TObject)
  private
    { Private declarations }
    FLastErrorMessage: String;
  public
    { Public declarations }
    constructor Create;
    destructor Destroy; override;
    function GetFrame(FrameTime: Double; const VideoFileName, ImageFileName: String): HRESULT;
    property LastErrorMessage: String read FLastErrorMessage;
  end;implementationuses
  DirectShow9, ActiveX, Jpeg, Graphics;constructor TVideoFrameGrabber.Create;
begin
  inherited Create;
  FLastErrorMessage := 'no error.';
end;destructor TVideoFrameGrabber.Destroy;
begin
  inherited Destroy;
end;function TVideoFrameGrabber.GetFrame(FrameTime: Double; const VideoFileName, ImageFileName: String): HRESULT;
var
  MediaDet: IMediaDet;
  MediaType: TAMMediaType;
  VideoStreams: Integer;
  BufferSize: Integer;
  Buffer: PByte;
  VideoWidth, VideoHeight: Integer;
  BMIHeader: PBitmapInfoHeader;
  BMPInfo: BitmapInfo;
  PData: pointer;
  HDCDest: HDC;
  StreamTime: Double;
  BitmapHdl: HBITMAP;
  NewBitmap: TBitmap;
  Jpeg: TJpegImage;
  FolderPath: String;
begin
  Result := S_FALSE;
  try
    if (CoCreateInstance(CLSID_MediaDet, nil, CLSCTX_INPROC, IMediaDet, MediaDet) = S_OK) then
    begin
      try
        if (MediaDet.put_Filename(VideoFileName) = S_OK)
          and (MediaDet.get_OutputStreams(VideoStreams) = S_OK)
          and (VideoStreams > 0)
          and (MediaDet.put_CurrentStream(0) = S_OK)
          and (MediaDet.get_StreamMediaType(MediaType) = S_OK)
          and (MediaDet.get_StreamLength(StreamTime) = S_OK) then
        begin
          if StreamTime >= FrameTime then
            StreamTime := FrameTime;
          VideoWidth  := PVideoInfoHeader(MediaType.pbFormat)^.bmiHeader.biWidth;
          VideoHeight := PVideoInfoHeader(MediaType.pbFormat)^.bmiHeader.biHeight;
          if Failed(MediaDet.GetBitmapBits(StreamTime, @buffersize, nil, VideoWidth, VideoHeight)) then
          begin
            FLastErrorMessage := 'GetBitmapBits(StreamTime, @buffersize, nil, VideoWidth, VideoHeight) failed - ' + VideoFileName;
            Exit;
          end;
          GetMem(Buffer, BufferSize);
          try
            if Failed(MediaDet.GetBitmapBits(StreamTime, @buffersize, Buffer, VideoWidth, VideoHeight)) then
            begin
              FLastErrorMessage := 'GetBitmapBits(StreamTime, @buffersize, Buffer, VideoWidth, VideoHeight) failed - ' + VideoFileName;
              Exit;
            end;
            BMIHeader  := PBitmapInfoHeader(Buffer);
            Inc(BMIHeader);
            pData      := BMIHeader;
            BMIHeader  := PBitmapInfoHeader(Buffer);
            ZeroMemory(@BMPInfo, sizeof(BITMAPINFO));
            CopyMemory(@BMPInfo.bmiHeader, bmiHeader, SizeOf(TBITMAPINFOHEADER));
            HDCDest := GetDC(0);
            if HDCDest = 0 then
            begin
              FLastErrorMessage := 'HDCDest = 0 - ' + VideoFileName;
              Exit;
            end;
            try
              BitmapHdl := CreateDIBitmap(HDCDest, BMIHeader^, CBM_INIT, pData, BMPInfo, DIB_RGB_COLORS);
              if BitmapHdl = 0 then
              begin
                FLastErrorMessage := 'CreateDIBitmap failed - ' + VideoFileName;
                Exit;
              end
              else
              begin
                NewBitmap := TBitmap.Create;
                try
                  NewBitmap.Handle := BitmapHdl;
                  Jpeg := TJpegImage.Create;
                  try
                    Jpeg.Assign(NewBitmap);
                    if Jpeg.Empty then
                    begin
                      FLastErrorMessage := 'Jpg.Empty -  ' + VideoFileName;
                      Exit;
                    end;
                    Jpeg.CompressionQuality := 100;
                    FolderPath := ExtractFilePath(ImageFileName);
                    if not DirectoryExists(FolderPath) then
                    begin
                      if not ForceDirectories(FolderPath) then
                      begin
                        FLastErrorMessage := 'ForceDirectories(' + FolderPath + ') failed.';
                        Exit;
                      end;
                    end;
                    Jpeg.SaveToFile(ImageFileName);
                  finally
                    Jpeg.Free;
                  end;
                finally
                  NewBitmap.Free;
                end;
              end;
            finally
              ReleaseDC(0, HDCDest );
            end;
          finally
            FreeMem(Buffer);
          end;
        end
        else
        begin
          if MediaDet.put_Filename(VideoFileName) <> S_OK then
            FLastErrorMessage := 'MediaDet.put_Filename(' + VideoFileName + ') failed.'
          else if MediaDet.get_OutputStreams(VideoStreams) <> S_OK then
            FLastErrorMessage := 'MediaDet.get_OutputStreams(' + IntToStr(VideoStreams) + ') failed.'
          else if VideoStreams <= 0 then
            FLastErrorMessage := 'VideoStreams = ' + IntToStr(VideoStreams)
          else if MediaDet.put_CurrentStream(0) <> S_OK then
            FLastErrorMessage := 'MediaDet.put_CurrentStream(0) failed.'
          else if MediaDet.get_StreamMediaType(MediaType) <> S_OK then
            FLastErrorMessage := 'MediaDet.get_StreamMediaType(MediaType) failed.'
          else if MediaDet.get_StreamLength(StreamTime) <> S_OK then
            FLastErrorMessage := 'MediaDet.get_StreamLength(StreamTime) failed.'
          else
            FLastErrorMessage := 'Unknown Error.';
          Exit;
        end;
      finally
        MediaDet := nil;
      end;
    end;
    Result := S_OK;
  except on E: Exception do
    FLastErrorMessage := E.Message;
  end;
end;end.