Sensoray 2224 Windows - Manual (Page 15)

Overlay
The 2226 has the capability to add text captions and bitmap images on to the video stream. There are a
total of 8 hardware windows to work with. Please note that multi-line captions may take up multiple
windows. The demo application currently only demonstrates one overlay region.
All overlay functions (except S2226_CopyBmpToOverlayZero) do not update the screen until
S2226_UpdateOverlay is called. If using multiple overlays, set them up first and then call
S2226_UpdateOverlay for maximum efficiency. S2226_CopyBmpToOverlayZero can be called to update
sub-regions of overlay window-0 immediately. When window-0 is set to the same size as the input
resolution, this effectively enables random rectangular updates across the entire screen without having
to download the entire overlay, as is done with the other functions when updated with
S2226_UpdateOverlay.
• S2226_OverlayText, S2226_OverlayTextIdx
• S2226_OverlayImage, S2226_OverlayImageIdx
• S2226_GetOverlayIdx
• S2226_OverlayBackgroundColor
• S2226_MoveOverlay
• S2226_OverlayDel, S2226_OverlayDelXY
• S2226_ClearOverlay
• S2226_UpdateOverlay
• S2226_ClearOverlayRegion
• S2226_SetOverlayRegion
• S2226_OverlayImageRaw
• S2226_CopyBmpToOverlayZero
Snapshots
Snapshots are uncompressed grabs from the 2226 in near real-time. They are captured directly in
hardware at the same video resolution as the input. They are not decoded from the encoded stream so
there will be no loss of quality due to compression. Due to USB bandwidth limitations, the snapshot
feature is only intended for intermittent grabs of the stream. The user must not attempt to capture at
anywhere near full frame rate using snapshots.
Snapshots are captured field by field. If using an interlaced source, the merge type should be specified.
The merge type determines how to put the fields back together. Please see the function reference for
more details.
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