Video capture device drivers use the DVM_STREAM messages sent to a VIDEO_IN channel to stream full motion video to the client-application. Your device driver will use the following messages while it is streaming video:
| Message | Description |
|---|---|
| DVM_STREAM_INIT | Initializes a video input stream. |
| DVM_STREAM_ALLOCBUFFER | Lets devices with substantial on-board memory to allocate capture buffers |
| DVM_STREAM_FREEBUFFER | Frees buffers allocated in hardware |
| DVM_STREAM_PREPAREHEADER | Requests that the driver prepare a data buffer for input. |
| DVM_STREAM_ADDBUFFER | Adds a buffer to the video input stream queue. |
| DVM_STREAM_START | Begins streaming video input. |
| DVM_STREAM_STOP | Ends video input streaming. |
| DVM_STREAM_UNPREPAREHEADER | Requests that a driver clean up the preparation previously done on a data buffer. |
| DVM_STREAM_FINI | Closes and deallocates a video stream. |