Ok, thanks for reply.
I tried with powerdvd11 trial, but I didn't get what I wanted : there are new zoom options, but I can only activate them if I activate "truetheater" (which seem to alter the video, in a good way, but it's still alteration I might not always want)
None of those options zoomed exactly as I wanted, even if "intelligent 2.35" and "intelligent" were close to it. (I mesured width + hight on screen with a ruler and calculated original ratio + zoom ratios)
I don't understand why this feature, which would be really simple to implement, is not in such a powerful software.
You say "nothing PowerDVD can do about it", but ... let me explain why I think this is wrong
You take a video of a wide format A, and encode black areas to make it fit a less wide format B. Now you have a video of B format on the DVD, and if you play it on a screen of format C, C being wider than B, you get black areas everywhere (top+bottom encoded in video, and left+right added by powerDVD to make the B format video fit the C format screen).
This is common and is A is wider than C, which will most often be the case, the math to zoom the video are realy simple : zoom from the width of B to the width of C (video takes all the with of the screen), and zoom the height with exact same factor
Of course, the video with that "newHight" will be higher than the screen, but just center it, and the areas that will automatically disappear are the artificial blacks areas which were added to go from A to B.
If C is wider than A, which I think will be a rare case, it's harder to do: either the software has to dynamically detect the artificial black areas, either the user has to choose what the A format was so that the software is able to calculate (but user most oftent won't know if A is 16/9, 2.35, 2.xx ...). If too hard to do, just implement the easy case where A is wider than C.
To conclude ... I tried to play my videos and DVDs using VLC and discovered is has the exact feature I need, for FREE ! It's called "crop" (or whatever is the name of the menu 3 rows under "zoom" in English). I just had to "crop" to a C format less wide than A (in my case, A is 2.xx and I cropped to the format of my screen, 16/10), and boom, it cuts the video to size of 16/10 and zooms the result to the size of my screen.
I just saved 60€ ^^
Hope cyberlink will be able to use the little math trick I described here or the same trick than VLC in order to improve powerDVD, because having such a commercial software not being able to do such a simple thing done by a free software is sad