IAMLine21Decoder::SetRedrawAlways method (il21dec.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The SetRedrawAlways method specifies whether the Line 21 Decoder filter redraws the entire output bitmap for each sample.
Syntax
HRESULT SetRedrawAlways(
BOOL bOption
);
Parameters
bOption
Specifies one of the following values.
| Value | Description |
|---|---|
| TRUE | The filter always redraws the entire bitmap. |
| FALSE | The filter does not always redraw the entire bitmap. (Default) |
Return value
Returns S_OK if successful, or an error code otherwise.
Remarks
Generally, applications should not call this method. The downstream mixer or renderer filter should call this method with the value TRUE if it writes into the buffers that it receives from the Line 21 Decoder filter. Redrawing degrades performance and increases CPU load, because it negates any potential optimizations.
Requirements
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | il21dec.h |
| Library | Strmiids.lib |