Posting Messages to Video Post

This section discusses the posting of messages in video post. There are three message types supported:

The progress message BMM_PROGRESS updates the dialog with how much of the image has been processed.
The check abort message BMM_CHECKABORT allows the plug-in to detect if the user has canceled the operation.
The text message BMM_TEXTMSG allows the plug-in to send a string to the video post "Progress Report" dialog.

These messages are sent via the Window API SendMessage() function listed below. The arguments for each message are listed as well as a single example of use.

LRESULT SendMessage(
 HWNDhwnd,     // handle of destination window
 UINTuMsg,     // message to send
 WPARAMwParam, // first message parameter
 LPARAMlParam  // second message parameter
);

BMM_PROGRESS

Sent by the plug-in to notify the host of its current progress.

wParam - Current amount processed.
lParam - Total amount to process.

BMM_CHECKABORT

Sent by the plug-in to check for process interruption. The host should set *lParam to FALSE if it's OK to continue or TRUE to abort the process.

wParam - Always 0.
lParam - Pointer to a BOOL.

BMM_TEXTMSG

Sent by the plug-in to display an optional text message to the "Progress Report" dialog while rendering in Video Post.

wParam - Pass 0
lParam - Pass a LPCTSTR.