Videomaker – Learn video production and editing, camera reviews › Forums › Technique › Miscellaneous Techniques › 4:3 vs. 16:9 question? › Most editing software does
Most editing software does not actually save stretched video – so what you are viewing in a media player might be misleading. I understand what you’re getting to with Windows Media Player. By my experience with Windows Media Player, large videos (mostly 720×480 and over) that are to large to fit are adjusted so that they fit the play screen. If the blank area of Windows Media Player is adjusted to a perfect square, then the video will be stretched so that it fits that way. If widescreen footage is played on a standard (non-widescreen) monitor in fullscreen mode, the image is squeezed horizontally so that it fits the screen.
If you save video in 16:9, you will get unstretched video in 16:9. Converting between fullscreen and widescreen causes the picture to be cropped horizontally or vertically so that it fits the apropriate size.