There sometimes is no logic to software. Or, no logic that we can understand
I'd guess the classic player is too old to recognize a newer video formatting option.
However, I just downloaded Windows Media Player Classic and it makes no difference - the videos are as square as always.
Could be you are using another codec (but I'm not sure how to check that).

Somehow that´s something I can´t respective I don´t want to believe. All computer matters should be logical processes, so it´only our too less knowledge, if we don´t understand something.



It´s called "Classic Player", but I think, it´s newer then the Windows Media Player.



Yes, I´m quite sure, the reason must be there. The codec matters are very complex and one nice day I have downloaded a free new codec package from the internet, since that day I have a problem here and there with the codecs. (But I needed to download new codecs, because some of my old ones didn´t work any more.)