Up to Gifferly...
- Added checkbox for outputting mp4. This feature uses ffmpeg if installed in the path. Otherwise the checkbox is disabled. This uses the right pix format for Firefox to be able to display the video. It's much faster and better quality than GIF.
- Moved all video generation to threads resulting in smoother UI operation.
- Added "Get FFmpeg" button that opens the download web page.
- [Mac] Implemented capturing screen data.