I have a really big problem since a rather long period of time already.
I'm owning a music YouTube channel and I'm creating audio visualizers for it regularly. It's nothing really special; just some kind of audio visualizer with a logo and background wiggle, nothing more.
But still my After Effects program seems to have issues with it... every single time I'm rendering a project of this kind, it renders a REALLY big file, much too big! Like 80GB for a 3 min. video!!!
I'm using QuickTime (H.264) in the rendering settings, and that worked perfectly in Windows 7 (max. 100MB for a 3-4 min. video), but since I'm using Windows 10 it doesn't seem to work properly any more. AVI is no alternative because it's even worse in terms of file size.
Now, as a workaround, I render every project a 2nd time in another program called "Easy H.264" which renders the videos just perfectly fine, same as Windows 7 did in former times.
What could be the problem now? How can I manage to get the normal file size back? I'm still on After Effects 2014, should I upgrade to 2015?
I'm using QuickTime (H.264) in the rendering settings,
Don't. you should encode your file with an encoding software like Adobe Media Encoder.
Your problem is that you have not taken the time to learn about video formats or study up on rendering. You have two options. Use the Adobe Media encoder and the standard h.264 presets to render your projects or you should be creating a digital intermediate using a suitable production codec and then rendering your h.264 MP4 in the Adobe Media Encoder. Your frame sizes and frame rates should come from the presets in composition settings. You should NEVER use QuickTime (h.264) because Apple is no longer supporting that format and it never worked well. There are a bunch of articles and posts that make that point.
Spend a little time studying up on the proper way to render your projects and make sure you are using the standard frame size and frame rate (HDTV 1080 is the most common) for your composition settings. You cannot fiddle with the composition settings unless you know exactly what you are doing.