Combining VHS/analog video with DV footage: What frame size should I capture at?

I'm working on a video project which requires that I combine DV
footage (captured from my minidv camera via firewire) along with
footage that's captured from VHS tapes using an old Osprey 100 video
capture card.

All of my DV footage will be at the 720x480 frame size. Is it
necessary that the I capture my VHS/analog video footage at 720x480 as
well? Or would it be best that I capture at 640x480 and then just
scale up during the editing? I have lots of analog video clips that I
need to capture, so I figured now would be the ideal time to ask this
question (before I get too deep into it).

I ask because the VFW driver for my Osprey capture card has the
ability to switch to CCIR601 and capture at 720x480. But when I
capture video at this size and then play it back, -- I can't help but
notice some strangeness in the way the video looks during scenes where
there's high motion (ie: choppy).

I understand that I'm dealing with 2 entirely different video formats,
and that standard VHS has less lines of resolution than DV. On that
note, -- am I distorting the VHS/analog-captured video by capturing it
at 720x480, and introducing problems that would be difficult to mask/
correct during the editing?

Thanks in advance,
- Yvan

 

Interesting question, I don't see any real problem in
principal with either way. Much would be dependent
on how your editing program handles different video
on the timeline. The highest potential for issues would
be in the decode to the editor's native format.

What I would expect is that capture to 720x480 should
work out best/ have less potential for problems. I was
an early advocate for 1/2 D1 capture for VHS source
analog video, and there can be some benefit to the smaller
format, in terms of bits per pixel, but the only real way to
be sure would be to do a test run using both methods.

If there is going to be any distortion applied when going
from VGA (640x480) to 720x480, it would be applied at
either stage, it shouldn't matter where it takes place. You
might want to find out which step uses the best scaling
algorithm, in your setup, i.e. Cubic over Bilinear.

Luck;
Ken

 

Almost certainly because the field order is inverted. DV uses the
opposite field order from most other capture formats. You should be
able to find an option in your editing software to "invert field
dominance".

Steve

The Doctor Who Restoration Team Website
http://www.restoration-team.co.uk

 

Good point, but that is one of the things to check for
and correct when adding material to a timeline anyway.

Luck;
Ken

 

I would capture to whatever is native for your editor. For example,
Premiere Pro treats DV-25 as native. When I need to include analog clips, I
capture them to 720x480 using the DV-25 codec. That way I don't have to
render within the editor to work with the clips, and everything is seamless.