/////////////////////////////////////////////////////////////////////
// Name: DisplayKeyFrames
//
// Parses the video stream and displays information about the
// samples that contain key frames.
//
// pStream: Pointer to a byte stream. The byte stream's current
// read position must be at the start of the ASF Data
// Object.
// pSplitter: Pointer to the ASF splitter.
/////////////////////////////////////////////////////////////////////
void DisplayKeyFrames(
IMFASFIndexer ai,
IMFByteStream pStream,
IMFASFSplitter pSplitter
)
{
const int cbReadSize = 2048; // Read size (arbitrary value)
int cbData; // Amount of data read
ASFStatusFlags dwStatus; // Parsing status
short wStreamID; // Stream identifier
bool bIsKeyFrame = false; // Is the sample a key frame?
int cBuffers; // Buffer count
int cbTotalLength; // Buffer length
long hnsTime; // Time stamp
IMFMediaBuffer pBuffer;
IMFSample pSample;
IMFByteStream[] aia = new IMFByteStream[1];
aia[0] = pStream;
int hr = ai.SetIndexByteStreams(aia, 1);
MFError.ThrowExceptionForHR(hr);
ASFIndexIdentifier ii = new ASFIndexIdentifier();
ii.guidIndexType = Guid.Empty;
ii.wStreamNumber = 2;
bool b;
int i1 = 100;
IntPtr ip = Marshal.AllocCoTaskMem(i1);
ai.GetIndexStatus(ii, out b, ip, ref i1);
long l;
PropVariant pv = new PropVariant(50000000L);
hr = ai.GetSeekPositionForValue(pv, ii, out l, IntPtr.Zero, out i1);
MFError.ThrowExceptionForHR(hr);
while (true)
{
// Read data into the buffer.
ReadDataIntoBuffer(pStream, cbReadSize, out pBuffer);
try
{
hr = pBuffer.GetCurrentLength(out cbData);
MFError.ThrowExceptionForHR(hr);
if (cbData == 0)
{
break; // End of file.
}
// Send the data to the ASF splitter.
hr = pSplitter.ParseData(pBuffer, 0, 0);
MFError.ThrowExceptionForHR(hr);
// Pull samples from the splitter.
do
{
hr = pSplitter.GetNextSample(out dwStatus, out wStreamID, out pSample);
MFError.ThrowExceptionForHR(hr);
if (pSample == null)
{
// No samples yet. Parse more data.
break;
}
try
{
// We received a sample from the splitter. Check to see
// if it's a key frame. The default is FALSE.
try
{
int i;
hr = pSample.GetUINT32(MFAttributesClsid.MFSampleExtension_CleanPoint, out i);
MFError.ThrowExceptionForHR(hr);
bIsKeyFrame = i != 0;
}
catch
{
bIsKeyFrame = false;
}
if (bIsKeyFrame)
{
// Print various information about the key frame.
hr = pSample.GetBufferCount(out cBuffers);
MFError.ThrowExceptionForHR(hr);
hr = pSample.GetTotalLength(out cbTotalLength);
MFError.ThrowExceptionForHR(hr);
Console.WriteLine(string.Format("Buffer count: {0}", cBuffers));
Console.WriteLine(string.Format("Length: {0} bytes", cbTotalLength));
hr = pSample.GetSampleTime(out hnsTime);
MFError.ThrowExceptionForHR(hr);
// Convert the time stamp to seconds.
double sec = (double)(hnsTime / 10000) / 1000;
Console.WriteLine(string.Format("Time stamp: {0} sec.", sec));
}
}
finally
{
SafeRelease(pSample);
}
} while ((dwStatus & ASFStatusFlags.Incomplete) > 0);
}
finally
{
SafeRelease(pBuffer);
}
}
Console.WriteLine("Done");
}
public static extern void MFCreateASFIndexer(
out IMFASFIndexer ppIIndexer);
void CreateIndexer(IMFASFContentInfo pContentInfo, out IMFASFIndexer ai)
{
MFAsfIndexerFlags f;
long l;
int i;
IMFMediaBuffer mb;
int hr;
hr = MFExtern.MFCreateASFIndexer(out ai);
MFError.ThrowExceptionForHR(hr);
hr = MFExtern.MFCreateMemoryBuffer(1000, out mb);
MFError.ThrowExceptionForHR(hr);
hr = ai.Initialize(pContentInfo);
MFError.ThrowExceptionForHR(hr);
hr = ai.GetIndexPosition(pContentInfo, out l);
MFError.ThrowExceptionForHR(hr);
hr = ai.GetFlags(out f);
MFError.ThrowExceptionForHR(hr);
hr = ai.SetFlags(f);
MFError.ThrowExceptionForHR(hr);
hr = ai.GetIndexByteStreamCount(out i);
MFError.ThrowExceptionForHR(hr);
hr = ai.GetCompletedIndex(mb, 0);
MFError.ThrowExceptionForHR(hr);
hr = ai.GetIndexWriteSpace(out l);
MFError.ThrowExceptionForHR(hr);
}
