Post by Ralph Rose on Mar 10, 2021 22:53:24 GMT
Are the odd and even lines picked apart and presented separate in each 50mhz frame or kept as one and then the second frame calculated? If so then surely the odd or even lines will be a jump ahead by a 50th of a second compared to their within frame counterpart?
Some people tend to mistake frames and fields as the same thing, they are not. 50 fields sec. creating 25 frames per second.
Two fields creates One frame etc.
The fields are blended together, or dropped on the Film telerecording to create 25 frames per second. So half of it was lost. (This also causes the side effect of jerky movement on some of the scenes originally recorded on film.)
To bring it back to 50 fields per second, a second field is calculated by motion estimate software, then interlaced to recover the video like movement.
Check the Restoration Team website about it. www.restoration-team.co.uk/ , then click on the Vidfire link on the left pane.
What is interesting is, you can have "progressive 50/59.94 frames per second" (575p50) (480p60) vs. "Interlaced 50/59.94 fields = 25/29.99 frames (575i) (480i)"
To my vision they look almost identical, and both have a smooth video like movement. I tend to like progressive 50/60 frames per second, as it does not show scan lines, like interlaced can. Older television equipment wasn't able to use 480p/575p or 480p60 / 575p50 etc, but all my new multi standard equipment can.
What I do at home is I have my HD television and/or computer convert the 480i = 59.94 fields/29.99 frames into 480p60 (or it's PAL counterparts) by deinterlacing and converting each field into it's own separate frame for playback. Thus I'm able to watch video like movement, without scan lines, and actually watch video on my computer as well. This way also preserves the film segments if applicable.