I’m not sure if this is a bug. But when I use H.264 Lossless Preset. When I go in the Advance tab and lower the quality from 100% to 85%. The exported file size increases by a massive amount. I would of thought it would decrease it? This occurs using the Stable release Shotcut 19.04 and also the Beta release Shotcut 19.06. I made a video unfortunately my mic was not captured in the video, so no sound sorry.
If this is known or has been reported already, I apologise. I tried searching here but couldn’t find a thread on it.