/// <summary>
/// 构建捕获图
/// </summary>
private void CreateGraph(string Resolution, int Frames)
{
if (_graphBuilder != null)
{
return;
}
_graphBuilder = (IFilterGraph2) new FilterGraph(); // 获取IFilterGraph2接口对象
_captureGraphBuilder = (ICaptureGraphBuilder2) new CaptureGraphBuilder2(); //获取ICaptureGraphBuilder2接口对象
int hr = _captureGraphBuilder.SetFiltergraph(this._graphBuilder); //将过滤器图形附加到捕获图
DsError.ThrowExceptionForHR(hr);
//将视频输入设备添加到图形
hr = _graphBuilder.AddFilter(_theCamera, "source filter");
DsError.ThrowExceptionForHR(hr);
//将视频压缩器过滤器添加到图形
if (_theCameraCompressor != null)
{
hr = _graphBuilder.AddFilter(_theCameraCompressor, "devicecompressor filter");
DsError.ThrowExceptionForHR(hr);
}
//将音频输入设备添加到图形
if (_theAudio != null)
{
hr = _graphBuilder.AddFilter(_theAudio, "audio filter");
DsError.ThrowExceptionForHR(hr);
}
//将音频压缩器过滤器添加到图形
if (_theAudioCompressor != null)
{
hr = _graphBuilder.AddFilter(_theAudioCompressor, "audiocompressor filter");
DsError.ThrowExceptionForHR(hr);
}
_mediaControl = (IMediaControl)this._graphBuilder;//获取IMediaControl接口对象
m_PictureReady = new ManualResetEvent(false);
//添加采样器接口.
sampleGrabber = new SampleGrabber() as ISampleGrabber;
// 配置SampleGrabber。添加预览回调
ConfigureSampleGrabber(sampleGrabber);
hr = _graphBuilder.AddFilter(sampleGrabber as IBaseFilter, "Frame Callback");// 将SampleGrabber添加到图形.
DsError.ThrowExceptionForHR(hr);
AMMediaType mediaType = new AMMediaType();
IntPtr pmt = IntPtr.Zero;
object oVideoStreamConfig;//视频流配置信息
hr = _captureGraphBuilder.FindInterface(PinCategory.Capture, MediaType.Video, _theCamera, typeof(IAMStreamConfig).GUID, out oVideoStreamConfig);
if (!(oVideoStreamConfig is IAMStreamConfig videoStreamConfig))
{
throw new Exception("Failed to get IAMStreamConfig");
}
hr = videoStreamConfig.GetFormat(out pmt);
if (hr != 0)
{
Marshal.ThrowExceptionForHR(hr);
}
Marshal.PtrToStructure(pmt, mediaType);
VideoInfoHeader videoInfoHeader = new VideoInfoHeader();
Marshal.PtrToStructure(mediaType.formatPtr, videoInfoHeader);
// 设置帧率
if (Frames > 0)
{
videoInfoHeader.AvgTimePerFrame = 10000000 / Frames;
}
//获取当前摄像头所支持的所有分辨率
var allResolution = GetCameraSupportResolution();
//当前所设置的分辨率此摄像头不支持
if (!allResolution.Contains(Resolution))
{
Resolution = allResolution[0];
}
// 设置宽度 设置高度
if (!string.IsNullOrEmpty(Resolution) && Resolution.Split('*').Length > 1)
{
videoInfoHeader.BmiHeader.Width = Convert.ToInt32(Resolution.Split('*')[0]);
videoInfoHeader.BmiHeader.Height = Convert.ToInt32(Resolution.Split('*')[1]);
}
// 复制媒体结构
Marshal.StructureToPtr(videoInfoHeader, mediaType.formatPtr, false);
// 设置新的视频格式
hr = videoStreamConfig.SetFormat(mediaType);
DsError.ThrowExceptionForHR(hr);
DsUtils.FreeAMMediaType(mediaType);
mediaType = null;
}
