Decklink Internal Keyer wired technically on/between SDI I/O

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Walter Sonius

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  • Joined: Wed May 03, 2017 9:53 am

Decklink Internal Keyer wired technically on/between SDI I/O

PostWed May 03, 2017 10:23 am

Keyer only application/driver request:

When using the internal keyer on a Decklink 4K SDI for instance with CasparCG it claims both the SDI output (mixed with internal keyer) and SDI input channels of the card. Therefor it is impossible to let a other application use or feed the SDI out, or have control whether or not to use the "SDI input" feed as live source to be keyed. This might be by design, to key graphics onto a live video feed from SDI input to SDI output.

However I would expect that if application X "only" uses the internal keyer, it would still let a other application Y (matched resolution/video standard) still use its SDI output albeit with the keyed content of application X "ontop". Even so let application Y control the passthrough whether or not use SDI input as a possible live feed or control its audio levels or not.

The benefits will both be control and quality as in being able to choose SDI input as a video source and let the hardware keyer mix 10bit yuv feed with lower quality RGBA 8bit while mainting VANC/VBIT teletext data etc.

This might be possible by driver/firmware patches as long as the Decklink keyer hardware has no physically dependency whether it is linked to the SDI input or output or somewhere in the middle.

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