Table of commonly correct and incorrect encoding. Incorrect encoding may be implied from wrong assumption about the shape of the active display area of the source.
Code:
Source IAR FAR PAR Comment
========= ===== ===== ===== ===============
PAL 4/3 5/4 15/11 12/11 Correct *
PAL 4/3 5/4 4/3 16/15 Incorrect
PAL 4/3 11/9 4/3 12/11 Correct *
PAL 16/9 5/4 20/11 16/11 Correct *
PAL 16/9 5/4 16/9 64/45 Incorrect
PAL 16/9 11/9 16/9 16/11 Correct *
NTSC 4/3 3/2 15/11 10/11 Correct *
NTSC 4/3 3/2 4/3 8/9 Incorrect
NTSC 4/3 22/15 4/3 10/11 Correct *
NTSC 16/9 3/2 20/11 40/33 Correct *
NTSC 16/9 3/2 16/9 32/27 Incorrect
NTSC 16/9 22/15 16/9 40/33 Correct *
* Absolutely correct with respect to ITU-T H.264 [1]
and approximately correct with respect to a possible interpretation [2] of (analogue) PAL / NTSC standards, ITU-R BT.601, and all digital standards based on them (D1, DV,...).
PAR: pixel aspect ratio, aka sample aspect ratio.
FAR: frame aspect ratio, aka display aspect ratio, aka picture aspect ratio.
IAR: image aspect ratio, aka storage aspect ratio. For example, 720/480 = 3/2 and 704/480 = 22/15.
Reference
[1] ISO/IEC MPEG - ITU-T VCEG Joint Video Team (JVT): Draft ITU-T H.264 (2002E) and ISO/IEC 14496-10:2002(E), aka AVC standard. Table E-1.
[2] Jukka Aho: A Quick Guide to Digital Video Resolution and Aspect Ratio Conversions.
http://www.iki.fi/znark/video/conversion/