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Q115763: VFW v1.1 DK "ICM_DRAW_START_PLAY" Message

Article: Q115763
Product(s): Microsoft Windows Software Development Kit
Version(s): 1.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 12-NOV-1999

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The information in this article applies to:

- Microsoft Video for Windows Development Kit, version 1.1 
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SUMMARY
=======

The ICM_DRAW_START_PLAY and ICM_DRAW_STOP_PLAY messages are not documented in
the "Programmer's Guide" included in the "Video for Windows Development Kit,
version 1.1" (VFW 1.1 DK).

This article describes these messages in detail for the purpose of assisting a
developer in writing a render driver.

MORE INFORMATION
================

The Installable Compression Manager (ICM) communicates with a renderer (also
known as a render driver) by sending messages to it. The renderer interprets the
message and responds accordingly.

The ICM_DRAW_START_PLAY message is sent either by the ICM or by an application
that calls the ICDrawStartPlay() command. This message is sent to tell the
driver the actual starting and ending times of a play operation. This message is
sent to the driver before any frame data is sent.

ICM_DRAW_START_PLAY is sent with two DWORD parameters, dwParam1 (the starting
time) and dwParam2 (the ending time). These times are typically interpreted as
frame numbers.

If the ending time is less than the starting time (dwParam2 < dwParam1), then
the segment plays backward.

The ICM_DRAW_STOP_PLAY message is sent when the ICDrawStopPlay() command is
issued to indicate a play operation is over. dwParam1 and dwParam2 are not used
with this message and should be ignored by the driver.

Additional query words: 1.10

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Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbVideoSearch kbSDKSearch kbVideoDK110
Version           : :1.1

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