There is a setting change for the HD1 that may improve black levels with some sources, especially HD cameras. You can apply this change using a PiVideo commmand:
pivideo –command 02010002000000F2
This setting does not persist through a source change or a reboot of the PiCapture board, so to return it to the original value simply change the source or you can use:
pivideo –command 02010002000000F7
Please note that you should have the latest PiVideo software installed (currently version 1.10).
We would appreciate any feedback about whether this is better for your application and should be the default for PiCapture HD1.