private static void UpdateAudioPart(IMediaDet mediaDet, MediaProperty mediaProperty)
{
int hr = 0;
AMMediaType mediaType = new AMMediaType();
hr = mediaDet.get_StreamMediaType(mediaType);
DsError.ThrowExceptionForHR(hr);
mediaProperty.audioSubType = mediaType.subType;
double streamLength;
hr = mediaDet.get_StreamLength(out streamLength);
DsError.ThrowExceptionForHR(hr);
mediaProperty.audioLength = TimeSpan.FromSeconds(streamLength);
if (mediaType.formatType == FormatType.WaveEx)
{
WaveFormatEx waveFormatEx = (WaveFormatEx)Marshal.PtrToStructure(mediaType.formatPtr, typeof(WaveFormatEx));
mediaProperty.channels = waveFormatEx.nChannels;
mediaProperty.samplesPerSec = ((float)waveFormatEx.nSamplesPerSec) / 1000;
mediaProperty.bitsPerSample = waveFormatEx.wBitsPerSample;
}
}
private static void UpdateVideoPart(IMediaDet mediaDet, MediaProperty mediaProperty)
{
int hr = 0;
AMMediaType mediaType = new AMMediaType();
hr = mediaDet.get_StreamMediaType(mediaType);
DsError.ThrowExceptionForHR(hr);
mediaProperty.videoSubType = mediaType.subType;
double streamLength;
hr = mediaDet.get_StreamLength(out streamLength);
DsError.ThrowExceptionForHR(hr);
mediaProperty.videoLength = TimeSpan.FromSeconds(streamLength);
if (mediaType.formatType == FormatType.VideoInfo)
{
VideoInfoHeader videoHeader = (VideoInfoHeader)Marshal.PtrToStructure(mediaType.formatPtr, typeof(VideoInfoHeader));
mediaProperty.resolution = new Size(videoHeader.BmiHeader.Width, videoHeader.BmiHeader.Height);
mediaProperty.bitsPerPixel = videoHeader.BmiHeader.BitCount;
mediaProperty.fourCC = FourCCToString(videoHeader.BmiHeader.Compression);
}
}
/// <summary>
/// 获取媒体的各种属性
/// </summary>
/// <param name="fileName">视频文件名(包含文件路径)</param>
/// <returns>媒体的各种属性</returns>
public static MediaProperty GetMediaProperty(string fileName)
{
int hr = 0; //接收函数返回值，以此判断调用函数成功与否
MediaProperty mediaProperty = new MediaProperty();
IMediaDet mediaDet = null;
try
{
mediaDet = (IMediaDet) new MediaDet(); //创建DirectShow的媒体探测对象
hr = mediaDet.put_Filename(fileName); //设置媒体探测对象的文件名（包含文件路径）
if (hr < 0)
{
DsError.ThrowExceptionForHR(hr);
}
mediaProperty.fileName = fileName;
int streamCount;
hr = mediaDet.get_OutputStreams(out streamCount);
DsError.ThrowExceptionForHR(hr);
for (int i = 0; i < streamCount; i++)
{
hr = mediaDet.put_CurrentStream(i);
DsError.ThrowExceptionForHR(hr);
Guid streamType;
hr = mediaDet.get_StreamType(out streamType);
DsError.ThrowExceptionForHR(hr);
if (streamType == MediaType.Audio)
{
UpdateAudioPart(mediaDet, mediaProperty);
}
else if (streamType == MediaType.Video)
{
UpdateVideoPart(mediaDet, mediaProperty);
}
else
{
continue;
}
}
if (mediaProperty.videoSubType != Guid.Empty)
{
mediaProperty.snapshot = GetSnapshot(mediaDet, mediaProperty.resolution.Width, mediaProperty.resolution.Height, mediaProperty.videoLength.TotalSeconds / 2);
}
}
finally
{
if (mediaDet != null)
{
Marshal.ReleaseComObject(mediaDet);
}
}
return(mediaProperty);
}
