IAVIStream::Read method (vfw.h)
The Read method reads data from a stream and copies it to an application-defined buffer. If no buffer is supplied, it determines the buffer size needed to retrieve the next buffer of data. Called when an application uses the AVIStreamRead function.
Syntax
HRESULT Read(
LONG lStart,
LONG lSamples,
LPVOID lpBuffer,
LONG cbBuffer,
LONG *plBytes,
LONG *plSamples
);
Parameters
lStart
Starting sample or frame number to read.
lSamples
Number of samples to read.
lpBuffer
Pointer to the application-defined buffer to contain the stream data. You can also specify NULL to request the required size of the buffer. Many applications precede each read operation with a query for the buffer size to see how large a buffer is needed.
cbBuffer
Size, in bytes, of the buffer specified by lpBuffer.
plBytes
Pointer to a buffer that receives the number of bytes read.
plSamples
Pointer to a buffer that receives the number of samples read.
Return value
Returns AVIERR_OK if successful or AVIERR_BUFFERTOOSMALL if the buffer is not large enough to hold the data. If successful, Read also returns either a buffer of data with the number of frames (samples) included in the buffer or the required buffer size, in bytes.
Remarks
For handlers written in C++, Read has the following syntax:
HRESULT Read(LONG lStart, LONG lSamples,
LPVOID lpBuffer, LONG cbBuffer,
LONG *plBytes, LONG *plSamples);
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | vfw.h |
| Library | Vfw32.lib |