[Feature Request] Add option to toggle video fit-to-window behavior #3125

The fewer issues I have to read, the more new features I will have time to implement, so I ask that you please try these things first

• Check out all the menus and keyboard shortcuts. Maybe the feature already exists?
• Try with the newest version from GitHub
• Read the documentation and FAQ, Known issues, Troubleshooting to see if the feature already exists
• See if someone already suggested this under Issues or Discussions

Description

Hello, I'd like LosslessCut to have an option to toggle the video frame's window fitting behavior. Currently, when a video with a resolution lower than the containing window is played, LosslessCut will scale it up to make it fit the window (losing some quality).

Such an option should prevent this from happening and keep the original size of the video when enabled (or disabled depending on implementation), with the exception of videos whose dimensions exceed the containing window's, which in such case it's best for them to be contained by scaling down to avoid cut-offs.

Using the built-in DevTools, I see that this can be easily achieved by toggling the object-fit property of the video player element between contain and scale-down.

For information of why I ask for this: I need to take snapshots of specific portions of the frames, which is something I do straightforwardly with Microsoft's Snipping Tool; thus I need the video to not be scaled when possible to preserve its original quality.