Doom9's Forum - View Single Post - Resolutions, Aspect Ratios And The ITU-R BT.601 Standard

Chibi Jasmin · 12th January 2003, 14:56

These are the correct values as fractions of integers...

DVD (D1=720)

PAL-anamorphic: 512/351 PAR 640/ 351 DAR
PAL-nonanam.: 128/117 PAR 160/ 117 DAR
NTSC-anam.: 96/ 79 PAR 144/ 79 DAR
NTSC-nonanam.: 72/ 79 PAR 108/ 79 DAR

SVCD (2/3 D1=480)

PAL-anamorphic: 256/117 PAR 640/ 351 DAR
PAL-nonanam.: 64/ 39 PAR 160/ 117 DAR
NTSC-anam.: 144/ 79 PAR 144/ 79 DAR
NTSC-nonanam.: 108/ 79 PAR 108/ 79 DAR

VCD

PAL: 128/117 PAR 1408/1053 DAR
NTSC: 72/ 79 PAR 528/ 395 DAR

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And here a litte table...will probably look screwed here, but you can try to read it line by line...parts in round brackets will try to explain how values interact with each other...sorry, if it looks weird, if it confuses you, just forget it, and use the values above, which are 100% correct! Note: it's just another way of expressing 1.xxx:1 fractions with integers, so no rounding error.

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Resizing of MPEG-sources compliant to ITU-R BT.601 standard

PAR=pixel aspect ratio – DAR=display aspect ratio

According to ITU-R BT.601:

PAL PAR 117/128 (y/x), x/y=1.094 [128/117] PAR
NTSC PAR 79/72 (y/x), x/y=0.911 [ 72/ 79] PAR

All correct resizing is based on 79/72 and 117/128.

anamorphic -> reduce height 3/4

DVD (D1=720)

PAL-anamorphic: 1.459:1 [512/351] PAR 1.823:1 [ 640/ 351] DAR (720x1.094 PAR=788, /432 (3/4 height) -> 1.823 DAR, 576x1.823=1050, /720=1.459 PAR)
PAL-nonanam.: 1.094:1 [128/117] PAR 1.368:1 [ 160/ 117] DAR (720x1.094 PAR=788, /576 -> 1.368 DAR)
NTSC-anam.: 1.215:1 [ 96/ 79] PAR 1.823:1 [ 144/ 79] DAR (720x0.911 PAR=656, /360 (3/4 height) -> 1.823 DAR, 480x1.823= 875, /720=1.215 PAR)
NTSC-nonanam.: 0.911:1 [ 72/ 79] PAR 1.367:1 [ 108/ 79] DAR (720x0.911 PAR=656, /480 -> 1.367 DAR)

SVCD (2/3 D1=480)

PAL-anamorphic: 2.188:1 [256/117] PAR 1.823:1 [ 640/ 351] DAR (1050x576 (2/3 D1=D1), 1050/480 (width)=2.188 PAR)
PAL-nonanam.: 1.641:1 [ 64/ 39] PAR 1.368:1 [ 160/ 117] DAR ( 788x576 (2/3 D1=D1), 788/480 (width)=1.641 PAR)
NTSC-anam.: 1.823:1 [144/ 79] PAR 1.823:1 [ 144/ 79] DAR ( 875x480 (2/3 D1=D1), 875/480 (width)=1.823 PAR)
NTSC-nonanam.: 1.367:1 [108/ 79] PAR 1.367:1 [ 108/ 79] DAR ( 656x480 (2/3 D1=D1), 656/480 (width)=1.367 PAR)

VCD

PAL: 1.094:1 [128/117] PAR 1.337:1 [1408/1053] DAR (352x1.094 PAR=385, /288=1.337:1 DAR)
NTSC: 0.911:1 [ 72/ 79] PAR 1.337:1 [ 528/ 395] DAR (352x0.911 PAR=321, /240=1.337:1 DAR)

12th January 2003, 14:56	#5 \| Link
Chibi Jasmin Registered User Join Date: Oct 2001 Posts: 800	These are the correct values as fractions of integers... DVD (D1=720) PAL-anamorphic: 512/351 PAR 640/ 351 DAR PAL-nonanam.: 128/117 PAR 160/ 117 DAR NTSC-anam.: 96/ 79 PAR 144/ 79 DAR NTSC-nonanam.: 72/ 79 PAR 108/ 79 DAR SVCD (2/3 D1=480) PAL-anamorphic: 256/117 PAR 640/ 351 DAR PAL-nonanam.: 64/ 39 PAR 160/ 117 DAR NTSC-anam.: 144/ 79 PAR 144/ 79 DAR NTSC-nonanam.: 108/ 79 PAR 108/ 79 DAR VCD PAL: 128/117 PAR 1408/1053 DAR NTSC: 72/ 79 PAR 528/ 395 DAR --- And here a litte table...will probably look screwed here, but you can try to read it line by line...parts in round brackets will try to explain how values interact with each other...sorry, if it looks weird, if it confuses you, just forget it, and use the values above, which are 100% correct! Note: it's just another way of expressing 1.xxx:1 fractions with integers, so no rounding error. --- Resizing of MPEG-sources compliant to ITU-R BT.601 standard PAR=pixel aspect ratio – DAR=display aspect ratio According to ITU-R BT.601: PAL PAR 117/128 (y/x), x/y=1.094 [128/117] PAR NTSC PAR 79/72 (y/x), x/y=0.911 [ 72/ 79] PAR All correct resizing is based on 79/72 and 117/128. anamorphic -> reduce height 3/4 DVD (D1=720) PAL-anamorphic: 1.459:1 [512/351] PAR 1.823:1 [ 640/ 351] DAR (720x1.094 PAR=788, /432 (3/4 height) -> 1.823 DAR, 576x1.823=1050, /720=1.459 PAR) PAL-nonanam.: 1.094:1 [128/117] PAR 1.368:1 [ 160/ 117] DAR (720x1.094 PAR=788, /576 -> 1.368 DAR) NTSC-anam.: 1.215:1 [ 96/ 79] PAR 1.823:1 [ 144/ 79] DAR (720x0.911 PAR=656, /360 (3/4 height) -> 1.823 DAR, 480x1.823= 875, /720=1.215 PAR) NTSC-nonanam.: 0.911:1 [ 72/ 79] PAR 1.367:1 [ 108/ 79] DAR (720x0.911 PAR=656, /480 -> 1.367 DAR) SVCD (2/3 D1=480) PAL-anamorphic: 2.188:1 [256/117] PAR 1.823:1 [ 640/ 351] DAR (1050x576 (2/3 D1=D1), 1050/480 (width)=2.188 PAR) PAL-nonanam.: 1.641:1 [ 64/ 39] PAR 1.368:1 [ 160/ 117] DAR ( 788x576 (2/3 D1=D1), 788/480 (width)=1.641 PAR) NTSC-anam.: 1.823:1 [144/ 79] PAR 1.823:1 [ 144/ 79] DAR ( 875x480 (2/3 D1=D1), 875/480 (width)=1.823 PAR) NTSC-nonanam.: 1.367:1 [108/ 79] PAR 1.367:1 [ 108/ 79] DAR ( 656x480 (2/3 D1=D1), 656/480 (width)=1.367 PAR) VCD PAL: 1.094:1 [128/117] PAR 1.337:1 [1408/1053] DAR (352x1.094 PAR=385, /288=1.337:1 DAR) NTSC: 0.911:1 [ 72/ 79] PAR 1.337:1 [ 528/ 395] DAR (352x0.911 PAR=321, /240=1.337:1 DAR)