Video File Size

I have a video file, (.mov), of 2.98 GB size. When I import it into iMovie and make a few small edits and then export it at full size and quality it comes out as a 22 GB file. How does it grow so much after being processed in iMovie. I would have expected it to not change at all, in fact be a little smaller seeing how I edited out some footage. Can someone educate me?

Uncompressed video takes up a LOT of space. HD footage runs at around 150MB per second, for example.

iMovie uncompressed the file when you edited it. The Quicktime app is just as bad.

You will now need to recompress the movie file, using a codec such as h264, which I think is one of the most common these days - offering good quality, but also good compression.

You could do this in iMovie (I think - I haven’t used it for years) or something like Handbrake, which is a free to download video tool.


OK, so iMovie uncompresses the video file. That explains the dramatic growth. So it is up to me to choose how much I want to recompress it for use/storage. Thanks for explaining that to me. I feel happier now I understand what is going on. Thanks.