Class MF2DBuffer

The IMF2DBuffer interface is supported by a media buffer whose multimedia data represents a 2D media type e.g. video. For these media types it is important to know the "pitch" of the buffer which indicates the number of bytes required to go from scanline to scanline. The IMF2DBuffer interface is obtained from a buffer by calling QueryInterface(). For each 2D media type a contiguous standard representation is defined which is designed to be compatible with the standard layout of a DirectX surface when represented by system memory. In this representation the surface pitch is always positive and equal to the number of bytes taken up by a single row of pixels padded out to a 4-byte boundary.

Applications may still access 2D buffers using IMFBuffer::Lock(). In that case the data in the buffer will always be in the standard contiguous format for the format of data represented by the buffer. An internal copy may be required on IMFBuffer::Lock() and IMFBuffer::Unlock() to achieve this. The copy will not occur if the buffer is already in the correct format. When a copy occurs an event will be generated to aid debugging performance issues resulting from the copy. Components that process 2D data should aim to use the IMF2DBuffer interface to access sample data.

Inheritance

object

DXComObject

MF2DBuffer

Implements

IDisposable

Inherited Members

DXComObject.Dispose()

DXComObject.AddRef()

DXComObject.Release()

DXComObject.QueryInterface(in Guid)

DXComObject.Handle

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: JeremyAnsel.DirectX.MediaFoundation

Assembly: JeremyAnsel.DirectX.MediaFoundation.dll

Syntax

[SecurityCritical]
public class MF2DBuffer : DXComObject, IDisposable

Constructors

MF2DBuffer(nint)

Initializes a new instance of the MF2DBuffer class.

Declaration

public MF2DBuffer(nint comPtr)

Parameters

Type	Name	Description
nint	comPtr

Fields

MF2DBufferGuid

The interface GUID.

Declaration

public static readonly Guid MF2DBufferGuid

Field Value

Type	Description
Guid

Methods

ContiguousCopyFrom(nint, uint)

The ContiguousCopyFrom method copies the contents of the caller's buffer which is in contiguous format into the buffer - correcting for the buffer's pitch as necessary.

Declaration

public void ContiguousCopyFrom(nint pbSrcBuffer, uint cbSrcBuffer)

Parameters

Type	Name	Description
nint	pbSrcBuffer	Pointer to where to copy the contiguous from.
uint	cbSrcBuffer	Number of bytes to copy. This must match the value returned by GetContiguousLength. If it doesn't this method returns E_INVALIDARG.

ContiguousCopyTo(nint, uint)

The ContiguousCopyTo method copies the contents of the buffer into the caller's buffer in contiguous format.

Declaration

public void ContiguousCopyTo(nint pbDestBuffer, uint cbDestBuffer)

Parameters

Type	Name	Description
nint	pbDestBuffer	Pointer to where to store the contiguous data to.
uint	cbDestBuffer	Number of bytes to copy. This must match the value returned by GetContiguousLength. If it doesn't this method returns E_INVALIDARG.

GetContiguousLength()

The GetContiguousLength method returns the number of bytes required store the buffer contents in contiguous format.

Declaration

public uint GetContiguousLength()

Returns

Type	Description
uint

GetScanline0AndPitch(out nint, out uint)

The GetScanline0AndPitch returns a pointer to the start of the first line and the pitch of the buffer. The memory pointer and pitch value are only valid while there is at least one outstanding Lock call with an unmactched Unlock call.

Declaration

public void GetScanline0AndPitch(out nint pbScanline0, out uint plPitch)

Parameters

Type	Name	Description
nint	pbScanline0	Pointer to a byte ponter where the pointer to the first byte of the top row of the buffer will be stored
uint	plPitch	Pointer to a count of bytes where the pitch of the buffer will be stored. This value can be added to a pointer to the start of a given row of the buffer to get the pointer to the start of the next row of the buffer.

IsContiguousFormat()

The IsContignousFormat method returns a BOOL value which is TRUE if the buffer is in contiguous format and FALSE if it is not in contiguous format.

Declaration

public bool IsContiguousFormat()

Returns

Type	Description
bool

Lock2D(out nint, out uint)

The Lock2D method ensures the buffer memory is accessible in the correct format and returns a pointer to the start of the first line and the pitch of the buffer. Each call to Lock2D must be matched by a corresponding call to Unlock2D. The memory pointer and pitch value are only valid while there is at least one outstanding Lock2D call with an unmactched Unlock2D call.

Declaration

public void Lock2D(out nint ppbScanline0, out uint plPitch)

Parameters

Type	Name	Description
nint	ppbScanline0	Pointer to a byte ponter where the pointer to the first byte of the top row of the buffer will be stored
uint	plPitch	Pointer to a count of bytes where the pitch of the buffer will be stored. This value can be added to a pointer to the start of a given row of the buffer to get the pointer to the start of the next row of the buffer.

Unlock2D()

The Unlock2D method unlocks the buffer. Each call to Lock2D must be matched by a call to Unlock2D. When there are no more outstanding Unlocks all existing pointers to the buffer and pitch values should be considered invalid.

Declaration

public void Unlock2D()

Implements

IDisposable