I just rendered a video of approx 12 minutes with the default preset for internet HD 1080/50p. The estimated filesize shows was 47MB, but after about one hour of rendering I ended up with a file of more than a GB.
Any experience with this ? Something I can do wrong ?
There are many, many variations to be adjusted when rendering your video. First of all is codec, then resolution and bitrate. Before we can help you better, we need to know what preset you used for your render and to make suggestions, what is the final goal for viewing of your video.