capFileAlloc macro (vfw.h)

Article
02/22/2024

The capFileAlloc macro creates (preallocates) a capture file of a specified size. You can use this macro or explicitly send the WM_CAP_FILE_ALLOCATE message.

Syntax

void capFileAlloc(
   hwnd,
   dwSize
);

Parameters

hwnd

Handle to a capture window.

dwSize

Size, in bytes, to create the capture file.

Return value

None

Remarks

You can improve streaming capture performance significantly by preallocating a capture file large enough to store an entire video clip and by defragmenting the capture file before capturing the clip.

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