Crop video option

[kashyap1113]

First I want to thank you for creating this awesome tool.
It would be nice, to have option to crop video.

[mifi]

Hi. I'm not sure how this would be possible to do with ffmpeg or even losslessly at all. Doing it in a lossy way would be outside the scope of this tool, I think.

[kashyap1113]

I think you are right. Cropping will need re-encoding, which is against the philosophy of this tool.

[tazztone]

avidemux can do lossless cutting and also re-encode with cropping

[mifi]

see #372

[ThreeDeeJay]

Hi. I'm not sure how this would be possible to do with ffmpeg or even losslessly at all. Doing it in a lossy way would be outside the scope of this tool, I think.

I think you are right. Cropping will need re-encoding, which is against the philosophy of this tool.

@mifi @kashyap1113 ffmpeg can crop losslessly using a bitstream flag (at least for h264) like this:
ffmpeg.exe -i "input.mp4" -c copy -bsf:v h264_metadata=crop_left=1920 "output.mkv"
This would convert a 3D Side by Side video (3840x1080) to 2D (single view that's 1920x1080)
But very important to note (and would probably warrant a warning to the user): it won't actually delete the unused area from the file.
It will just hide it so the size will remain basically the same as if both views were still visible, but I think all the flag does is to tell the player to crop the video on-the-fly. Useful to crop stuff for YouTube, which should delete the unused stuff (though I think YT keeps a copy of the original, but only used internally for re-encodes) so it's not a good idea to crop out sensitive data since the crop is reversible IIRC.

[mifi]

@ThreeDeeJay thanks for your input. See #643

[ThreeDeeJay]

Woweee guess you guys are already way ahead of me lol 👌