🚀 go-pugleaf

Most mac-II models will record direct to video with the addition of
some init or something, which is available from apda for about $30.
The quadras also have some built-in circuit for de-interlacing video,
so you don't get bouncing 1-pixel lines.

Rasterops 364 and 24stv (roughly $800-$1400) will encode video
and digitize video, though the video cannot be saved to disk at 30fps.  
They will also display a video source in a window.

My impression is that the encoder with these products is not
'broadcast quality' if that is important.  Candidates for this
nebulous quality are the Nuvista and possibly the Radius Videovision.
Alternatively you can probably interface to any external high quality
encoder, once the mac signal is down to ntsc frame rates & resolution.