NTSC 4:3 to PAL 16:9

[mantis2k]

How would I convert a DVD from NTSC 4:3 to PAL 16:9 with an AviSynth script? I'd imagine it would go something like this...

1) Crop away all of the borders.
2) Deinterlace.
3) BicubicResize height x 1.3333.
4) Add borders to make picture height 576.
5) Change FPS to 25.

Is this acceptable, or would the aspect ratio become distorted, due to the NTSC to PAL conversion and square pixels? Taking this into consideration, I would imagine the logical method would go something like this...

1) Deinterlace.
2) BicubicResize height to 576.
3) Crop away part of the borders (72,72)
4) BicubicResize height to 576.
5) Change FPS to 25.

However, this involves 2 resizes! Again, I wonder if my first solution is acceptable for maintaining original aspect ratio, or is there a better mathematical solution with only 1 resize?

Any help would be much appreciated!

[scharfis_brain]

NTSC <-> PAL conversions introduce a 1:1.2 factor in vertical size
letterboxed <-> anamorphic conversions introduce a 1:1.3333 factor in vertical size.

this means:


NTSC LB -> PAL LB:
bicubicresiye(width,576) make 480 lines become 576 lines (576 = 480 * 1.2)

NTSC LB -> PAL WS:
crop(0,60,0,-60) make 480 lines become 360 lines
bicubicresize(width,576) make 360 lines become 576 lines (576 = 360 * 1.2 * 1.333)


if you need to convert from WS to LB you need to divide by 1.3333
and if you wish to convert from PAL to NTSC you have to divide by 1.2

[mantis2k]

Even though you once explained this to me before, I had forgotten about the 2nd magic number, 1.2! :D Thanks for reminding me! ;) You explain the theory well....