How to crop correctly. A guide using Megui.

[Ghitulescu]

PAL analogue is 702 and a bit x 575, but 704x576 is an exactly equivalent PAR+DAR.

DV is always 720, and not always (or even mostly) with black borders.

Cheers,
David.

You're right I've checked again, after 9 years my memory faded a lot.

Around 2000 I got my first MiniDV camcorder, a Sharp, that recorded 720x576 wherein the leftmost 16 pixels were black. I've asked in one of the newly created digital forums and I was told this story, I didn't care too much since that was inside the overscan anyway. Since then I never inquired the values again, because I do all my work in hardware.

[Alex_ander]

If we discuss analog, there is one value set: 711 samples per line.

Your numbers are correct for NTSC, 711 is the visible part of image line captured with the standard ITU's sample frequency 13.5 MHz (unified for PAL/NTSC) and the standard number of samples per line (720 in both cases). Vertically there are 485 active lines in analog video and those 2 numbers correspond to the standard 4:3 AR. As in case of PAL, the number of captured lines was rounded to a multiple of 16 (by cropping to 480). So in case of NTSC the standard captured image can't be 4:3 by visible part (unless cropped after capture), while 704x480 area within it represents the standard AR. If stored as 720x480, cropping 711 to 704 is not necessary (but useful for encoding).