Liam (https://goodingsweb.com) has shared his findings on tweaking ffmpeg output with h.264, he has taken a 174MB flv file down to just 24MB (86% reduction in file size).

There is no noticeable difference in quality either, you can follow the forum thread here: https://flowplayer.org/forum/7/12671.

Click the video for a preview of Liam’s settings:

[FLOWPLAYER=https://www.fightnightlive.co.uk/mp4/87.mp4,600,255]