Detecting analogue video signal

[leoenc]

Does someone know if it's possible to detect an analogue (i.e. VHS) video signal coming through a capture card?

I would like to be able to write some code to automatically capture the video signal once it is detected and end the capture when it is gone.

With digital (SDI) I know it's possible (plus usually those sources have RS-422 control anyway so it isn't required), but with analogue I can't find any solution, using capture cards like Decklink or Aja.

[jmac698]

There is such a thing - I notice when I go into my capture card properties, there's a greyed checkbox for signal detected. I know that some chips detect the signal and determine the video standard. There should be some way of doing it, in awkward fashion it could be bringing up that window and checking it, it could be a registry value which is changed, finally there's probably an official way to do it if you read the SDK docs carefully.

[jmac698]

I might ask on virtualdub forums, I'm sure Avery Lee knows.