I need a 4K H.264 MP4 that still looks good on a large TV, but the highest preset makes a huge file. How do I find the point where extra bitrate stops helping?
Make several short exports at increasing bitrates and compare the hardest scene. At some point the visual gain becomes tiny while file size continues to grow.
Codecs & export
If the playback target supports HEVC, it can reach similar quality at lower bitrate, but that trades compression efficiency against compatibility and decode requirements.
Judge moving footage, not only still frames. Water, smoke, confetti, foliage and pans reveal bitrate limits quickly.
I need H.264 for client-device compatibility, but I can still tune bitrate instead of automatically choosing the largest preset.