- Posts: 3
- Joined: Mon Oct 25, 2021 3:31 pm
- Real Name: Nick Clarke
Hi All,
I'm working on some Teleprompting software (C++), which currently works correctly using external keying - however we also want it to have the option of internal keying.
I have changed the settings as per the documentation (which, as far as I can see, is simply changing 'true' to 'false' in the call to Enable, and changing the 'supported' checks from external to internal), and set up a test rig with an fairly old Decklink Quad card, using the first channel with the input on SDI pin 2 and output on pin 3. The card reports that it supports internal keying, and I get my teleprompt output on the SDI - however the background is black, not showing the source.
I believe that the rendering code is giving the correct alpha (it is initialising the whole image to all 0s, which I believe is correct for fully transparent black in BGRA8? I've tried setting the 'fill' to fully transparent, and it then appears black on the output exactly the same as the background), and I've checked that the input looks correct when captured directly to disk using FFmpeg.
Does anyone have any ideas what I might have missed? I'm assuming there must be another setting somewhere that needs to be different between the two modes? The SDK is not reporting any errors, which I presume it would do in the case of something like a format mismatch? I've tried both 1080p25 and 1080i50 sources.
This is using the latest SDK on Ubuntu.
Many thanks!
I'm working on some Teleprompting software (C++), which currently works correctly using external keying - however we also want it to have the option of internal keying.
I have changed the settings as per the documentation (which, as far as I can see, is simply changing 'true' to 'false' in the call to Enable, and changing the 'supported' checks from external to internal), and set up a test rig with an fairly old Decklink Quad card, using the first channel with the input on SDI pin 2 and output on pin 3. The card reports that it supports internal keying, and I get my teleprompt output on the SDI - however the background is black, not showing the source.
I believe that the rendering code is giving the correct alpha (it is initialising the whole image to all 0s, which I believe is correct for fully transparent black in BGRA8? I've tried setting the 'fill' to fully transparent, and it then appears black on the output exactly the same as the background), and I've checked that the input looks correct when captured directly to disk using FFmpeg.
Does anyone have any ideas what I might have missed? I'm assuming there must be another setting somewhere that needs to be different between the two modes? The SDK is not reporting any errors, which I presume it would do in the case of something like a format mismatch? I've tried both 1080p25 and 1080i50 sources.
This is using the latest SDK on Ubuntu.
Many thanks!