A common feature among video editors similar to Kdenlive is that they estimate the output file depending on the chosen resolution, codecs and audio/video quality, so that users can have a good idea of how big the result of each combination of options will be. Also, the "quality bar" is currently subjective since there's no way to preview it or at least tell the output size. Please consider implementing this calculation to the "Render" window of Kdenlive. I've found an abandoned issue about this on the archived bug tracker, but it doesn't seem to have been imported: https://bugs.kdenlive.org/print_bug_page.php?bug_id=873 Version 16.04.3 KDE Neon 5.7
I don't see any way to implement this in any sensible manner, especially as our encoding engine is ffmpeg, and ffmpeg to the best of my knowledge doesn't implement any render output prediction. From my own projects I know that I have footage that causes high variations in rendered output size, depending on the kind of footage. So a short clip of real video causes 25% growth, despite being only 40s as opposed to 15mins of total runtime. See also http://superuser.com/questions/349590/how-can-i-find-out-how-big-my-encoded-file-will-be
I see. That's unfortunate.