one more question about avi file's pixel aspect ratio

[compusic]

as I have learned before that avi file does not support par other than 1:1, since avi was first coined for video on computer. the link is below:
http://forum.doom9.org/showthread.php?t=123113

if a avi file with other par is played back on pc, nearly all the players will suppose a 1:1 par, and won't make adjusting for the display, quick time's mov file has the same problem. I don't remember clearly at that time what codec those avi and mov files used, maybe in uncompressed format and some other codecs.

but now I just encounter a problem. when I play back avi file with dv codec ( par is 1.067), I find that the displayed frame aspect is correct, that means the players make adjusting for the par! the players I use are media player classic and windows media player 9. and I use quick time player 7 to play back mov file with dv codec, the fame ratio is correct too!

then I play back some other umcompressed avi with different par, the dar is not correct!

how can it be? the problem makes me crazy! nearly 99 out of 100 times, I'm not sure whether the avi file can be displayed correctly on the computer.

[foxyshadis]

If the PAR is held in the bitstream, and not the container, then it's up to the codec to parse and signal that information to the renderer. Obviously your DV codec does, and most mpeg decoders will, but apparently not whatever else you're using. (If by uncompressed you mean literally no codec, just raw samples, then those can't have a PAR since they don't have a codec or any private information at all.)

[Tack]

ODML extends AVI and includes aspect ratio in the vprp header. And, as foxyshadis said, the aspect can also be stored in the bitstream itself -- for MPEG4, for example, it can be stored in the VOL header.