you write -
I cannot use kona for realtime downconversion because there is no analog audio output from the card
this is incorrect information. Every AJA Kona 3 should be purchased with the AJA K3 box. This will give you analog audio output, which can go into your Beta VTR, so you can do a HD-SD downconvertion to analog Beta. If you don't have a K3 box, BUY ONE TOMORROW.
you know, i can recognize analog audio output when i see one,
but production for which i work as freelance does not have one, i checked and don't have time, you know, those bloody deadlines, to go to shopping.
I solve my problem, but, anyway, thank you again for your insightful advice.