How do I reduce the size of a huge MP4 video?

You can try using something such as ffmpeg or mencoder to reencode it with a lower bitrate, e.g.: Calculate the bitrate you need by dividing your target size (in bits) by the video length (in seconds). For example for a target size of 1 GB (one gigabyte, which is 8 gigabits) and 10 000 seconds of video (2 h 46 min 40 s), use a bitrate of 800 000 bit/s (800 kbit/s): Additional options that might be worth considering is setting the Constant Rate Factor, which lowers the average bit rate, but reta…