HDMI workflow is not recommended for many reasons, It is not suitable for Rec. 601 SD video, you get baked in artifacts that you can never get rid off, Capturing lossless AVI 4:2:2 gives you a clean video to start with, whether editing, de-interlacing or simply encoding to a playable format.

Yep, Usually happens when capturing and encoding on the fly, to save the CPU resources it uses the lowest compression setting, This why high quality encoding is lower than the real time playback speed, few frames a second.

What monitor are you using? On my monitor the tape playing and the captured file look almost identical. I am looking through the video clip over and over again. I am not getting the plasticky look you are seeing like in the screenshot you provided and I went through vdub frame by frame and not seeing the de interlace errors in the screenshot.

Please take a look at these two clips without the component adapters in between using the capture card software (no filters). Compare the third lossless clip with all the previous sample clips. Is it better or worse?

The third capture looks like the right job, The other two are cropped and re sized back to 720x480, badly de-interlaced, that's why they are bad.

The third one looks much better. However, VirtualDub's inverse telecine filter has trouble with it.

How do I fix the 3rd one?