Renders randomly gigantic in size

Hello, This is my first post here. I am editing a multicam clip with 3 4k angles. I am working with proxies. I have background rendering on. I am adjusting zoom and position on clips of generally the same length. Everything seems to work swiftly. The rendering takes a second or 2. It seems that after a while these same clips will start taking a very long time to render. When I view the rendered files in the library, there seems to be a huge difference in file size of what are, again, generally the same types of clips. I am identifying these by watching the times of the renders and comparing the ones that render fast to the slow ones. The fast ones average around 100MB and the slow ones can go up to 100GB. Again, these are basically the same types of clips being rendered.

So it doesn't seem to be a performance issue. It just appears that for some reason virtually the same type of clips render extremely larger than others at random times. Any suggestions as to what is happening?

Thanks

If you're working in Proxy mode you can most likely turn off background rendering. If everything plays fine you can then delete the render cache and recover a ton of disk space. If there are sections that do have trouble playing in real-time, you can always just render those sections.

thanks for reply. Im not having any playback issues. I am just curious why clips that generally have identical fx applied and lengths seem to be randomly rendered as gigantic files compared to most of the other same types of clips. In other words, a clip that is zoomed 150% that is 5 sec long will be 100MB render, and another clip that is the same will be 100GB, and thus takes much longer to render.

Without seeing your specific project settings and media info, I can't say why intermediate renders would be different. What I am saying is why bother even worrying about it? If you are not experiencing playback issues, turn off background rendering and save your drive space for final exports.

I'm curious how you're finding the sizes of the render files. Where are you seeing this?

Thanks. 

I am not really worried about it, just curious. I am checking the file sizes inside the library in the Render Files folder. I am sorting them by time and just checking the size of the newest file when there is render that takes a very long time (because it is very large).

It’s probably large because it’s a long, continuous render. Because there isn’t any real background rendering, files often get broken into smaller chunks when interrupted by any other process.

But they are all basically the same length clips. In other words, a 5 second clip one time will take a second or 2 to render and be about 100mb and then the next 5 second clip will take minutes and be 100gb. And it’s basically the same zoom and position fx applied to each. I’m more just curious as to why

Zibon wrote:

a 5 second clip one time will take a second or 2 to render and be about 100mb and then the next 5 second clip will take minutes and be 100gb.

I'm not sure what's going on, but this comment is definitely concerning.  There should be absolutely no way that a 5 second clip should produce a 100GB render file.  Even if you have an 8K or 16K multicam clip, 100GB for a 5 second piece seems improbable, unless you have 25 or 30 angles in that multicam.  10 or 12 streams of a 4K clip in a multicam of 5 seconds shouldn't create anywhere near that size of a render file.  Are you dealing with stabilization on any of these clips?  That size may be reporting incorrectly for some reason.