[MacDV] Re: questions on progressive scan (2 types)

Mark M. Florida markflo at mac.com
Wed Jun 11 13:33:33 PDT 2003


> -------------------- Begin Original Message --------------------
> 
> Message text written by Mark M. Florida
> 
> "Actually, I disagree.  The most important factor for freezing motion is
> not
> whether it's interlaced or not, but the *shutter speed* of the camera.  A
> higher shutter speed (1/250 sec. or higher) will freeze the motion.  And if
> this higher shutter speed was used with a progressive video signal (or even
> "quasi-progressive") that should yield the clearest still frames and slow
> motion possible."
> 
> -------------------- End Original Message --------------------
> 
> I think Tom said "review motion" not "freeze". IMO frame rate is most
> important for studying details of movements. If you have a shutter time of
> 1/250 sec and 30 frames per second playback would perhaps look a little
> stroboscopic.
> With deinterlaced video you have a shutter time of about 1/60 sec and 60
> frames/sec = smooth playback.
>
> My €0.02. (worth slightly more than your $0.02 at the moment   ;-)
> 
> Jan.

I guess my point was that using a 1/60 sec. shutter speed the image would be
blurry, but at 1/250 it would be clearer when watching in slow-motion so one
could review the *motion* and not the *motion blur*.

Maybe a combination of a faster shutter speed to keep the image crisp and
deinterlacing to get rid of the interlacing artifacts when viewing on a
computer screen...  A compromise to our two differing solutions perhaps?

Or if the goal is jut to review in *real-time* on a computer monitor, just
re-encode it at a smaller size (320x240 w/MJPEGA, using one field) to cut
the resolution in half, thus eliminating the interlaced fields.

2 cents plus 2 cents...

- Mark



More information about the MacDV mailing list