I made a 3 minute video and rendered it with quicktime format and h.264 codec which came out to be 1.8GB. The video consists of a 3 minute long mp3 (a song), 2 pictures, some light leaks, and a title.
I want to strongly mention that I have done a previous project of the same type with the same settings which was actually a longer video but it came out to be only 393 MB
I honestly do not know what the problem is. My 3 minute video shouldnt be even 500 MB yes its almost 2 GB.
Did you set a bitrate limit for the Quicktime H.264?
Or if you don't need the Quicktime .MOV wrapper just encode straight to H.264 .MP4 and choose an appropriate output format. Broadcast > H.264 > Match source - High bitrate > works really well for me. (~32Mbps)