// This returns the default or attempts to compute it, in its absence.
public void GetDefaultStride(out int pnStride)
{
int nStride = 0;
bool bFailed = false;
// First try to get it from the attribute.
try
{
int hr = GetMediaType().GetUINT32(MFAttributesClsid.MF_MT_DEFAULT_STRIDE, out nStride);
MFError.ThrowExceptionForHR(hr);
}
catch
{
bFailed = true;
}
if (bFailed)
{
// Attribute not set. See if we can calculate the default stride.
Guid subtype;
int width = 0;
int height = 0;
// First we need the subtype .
GetSubType(out subtype);
// Now we need the image width and height.
GetFrameDimensions(out width, out height);
// Now compute the stride for a particular bitmap type
FourCC f = new FourCC(subtype);
int hr = MFExtern.MFGetStrideForBitmapInfoHeader(f.ToInt32(), width, out nStride);
MFError.ThrowExceptionForHR(hr);
// Set the attribute for later reference.
SetDefaultStride(nStride);
}
pnStride = nStride;
}
// Extracts the FOURCC code from the subtype.
// Not all subtypes follow this pattern.
public void GetFourCC(out int pFourCC)
{
Debug.Assert(IsValid());
Guid guidSubType;
GetSubType(out guidSubType);
FourCC f = new FourCC(guidSubType);
pFourCC = f.ToInt32();
}
//-----------------------------------------------------------------------------
// GetDefaultStride
//
// Gets the default stride for a video frame, assuming no extra padding bytes.
//
//-----------------------------------------------------------------------------
private static int GetDefaultStride(IMFMediaType pType, out int plStride)
{
int lStride = 0;
plStride = 0;
// Try to get the default stride from the media type.
int hr = pType.GetUINT32(MFAttributesClsid.MF_MT_DEFAULT_STRIDE, out lStride);
if (Failed(hr))
{
// Attribute not set. Try to calculate the default stride.
Guid subtype = Guid.Empty;
int width = 0;
int height = 0;
// Get the subtype and the image size.
hr = pType.GetGUID(MFAttributesClsid.MF_MT_SUBTYPE, out subtype);
if (Succeeded(hr))
{
hr = MFGetAttributeSize(pType, MFAttributesClsid.MF_MT_FRAME_SIZE, out width, out height);
}
if (Succeeded(hr))
{
FourCC f = new FourCC(subtype);
hr = MediaFoundation.MFExtern.MFGetStrideForBitmapInfoHeader(f.ToInt32(), width, out lStride);
}
// Set the attribute for later reference.
if (Succeeded(hr))
{
hr = pType.SetUINT32(MFAttributesClsid.MF_MT_DEFAULT_STRIDE, lStride);
}
}
if (Succeeded(hr))
{
plStride = lStride;
}
return hr;
}
//-------------------------------------------------------------------
// SetVideoType
//
// Set the video format.
//-------------------------------------------------------------------
public int SetVideoType(IMFMediaType pType)
{
int hr = S_Ok;
Guid subtype;
MFRatio PAR = new MFRatio();
// Find the video subtype.
hr = pType.GetGUID(MFAttributesClsid.MF_MT_SUBTYPE, out subtype);
if (Failed(hr)) { goto done; }
// Choose a conversion function.
// (This also validates the format type.)
hr = SetConversionFunction(subtype);
if (Failed(hr)) { goto done; }
//
// Get some video attributes.
//
// Get the frame size.
hr = MFGetAttributeSize(pType, MFAttributesClsid.MF_MT_FRAME_SIZE, out m_width, out m_height);
if (Failed(hr)) { goto done; }
// Get the image stride.
hr = GetDefaultStride(pType, out m_lDefaultStride);
if (Failed(hr)) { goto done; }
// Get the pixel aspect ratio. Default: Assume square pixels (1:1)
hr = MFGetAttributeRatio(pType, MFAttributesClsid.MF_MT_PIXEL_ASPECT_RATIO, out PAR.Numerator, out PAR.Denominator);
if (Succeeded(hr))
{
m_PixelAR = PAR;
}
else
{
m_PixelAR.Numerator = m_PixelAR.Denominator = 1;
}
FourCC f = new FourCC(subtype);
m_format = (Format)f.ToInt32();
// Create Direct3D swap chains.
hr = CreateSwapChains();
if (Failed(hr)) { goto done; }
// Update the destination rectangle for the correct
// aspect ratio.
UpdateDestinationRect();
done:
if (Failed(hr))
{
m_format = Format.Unknown;
m_convertFn = null;
m_bmpconvertFn = null;
}
return hr;
}
//-----------------------------------------------------------------------------
// GetDefaultStride
//
// Gets the default stride for a video frame, assuming no extra padding bytes.
//
//-----------------------------------------------------------------------------
private static int GetDefaultStride(IMFMediaType pType, out int plStride)
{
int lStride;
plStride = 0;
// Try to get the default stride from the media type.
var hr = pType.GetUINT32(MFAttributesClsid.MF_MT_DEFAULT_STRIDE, out lStride);
if (Failed(hr))
{
// Attribute not set. Try to calculate the default stride.
Guid subtype;
var width = 0;
// ReSharper disable once TooWideLocalVariableScope
// ReSharper disable once RedundantAssignment
var height = 0;
// Get the subtype and the image size.
hr = pType.GetGUID(MFAttributesClsid.MF_MT_SUBTYPE, out subtype);
if (Succeeded(hr))
{
hr = CProcess.MfGetAttributeSize(pType, out width, out height);
}
if (Succeeded(hr))
{
var f = new FourCC(subtype);
hr = MFExtern.MFGetStrideForBitmapInfoHeader(f.ToInt32(), width, out lStride);
}
// Set the attribute for later reference.
if (Succeeded(hr))
{
hr = pType.SetUINT32(MFAttributesClsid.MF_MT_DEFAULT_STRIDE, lStride);
}
}
if (Succeeded(hr))
{
plStride = lStride;
}
return hr;
}
//-------------------------------------------------------------------
// SetVideoType
//
// Set the video snapFormat.
//-------------------------------------------------------------------
public int SetVideoType(IMFMediaType pType)
{
Guid subtype;
var PAR = new MFRatio();
// Find the video subtype.
var hr = pType.GetGUID(MFAttributesClsid.MF_MT_SUBTYPE, out subtype);
try
{
if (Failed(hr))
throw new Exception();
// Choose a conversion function.
// (This also validates the snapFormat type.)
hr = SetConversionFunction(subtype);
if (Failed(hr))
throw new Exception();
//
// Get some video attributes.
//
// Get the frame size.
hr = CProcess.MfGetAttributeSize(pType, out width, out height);
if (Failed(hr))
throw new Exception();
// Get the image stride.
hr = GetDefaultStride(pType, out lDefaultStride);
if (Failed(hr))
throw new Exception();
// Get the pixel aspect ratio. Default: Assume square pixels (1:1)
hr = CProcess.MfGetAttributeRatio(pType, out PAR.Numerator, out PAR.Denominator);
if (Succeeded(hr))
{
pixelAR = PAR;
}
else
{
pixelAR.Numerator = pixelAR.Denominator = 1;
}
var f = new FourCC(subtype);
format = (Format) f.ToInt32();
// Create Direct3D swap chains.
hr = CreateSwapChains();
if (Failed(hr))
throw new Exception();
// Update the destination rectangle for the correct
// aspect ratio.
UpdateDestinationRect();
}
finally
{
if (Failed(hr))
{
format = Format.Unknown;
m_convertFn = null;
}
}
return hr;
}