I need some help with interpolation videos, lots of detail in post

[bradwiggo]

Originally Posted by johnmeyer

Mediainfo often reports strange numbers. You can find all sorts of posts about this. As already advised, ignore the numbers for this video.

What would be the expected file size increase when interpolating from 24 to 60? Would it be 2.5 times as big, as there are 2.5 times as many frames, or would it be even bigger? As at the moment I have a 3.1 times increase in file size.

[Sparktank]

It's the settings that matter.

You can use 2-pass, or you can use lower settings, etc.

Just use a CRF of 18 with a preset of veryslow, and you'll do fine.

[lansing]

From my experience, bobbing a tv-series from 30fps to 60fps only adds about 15%-20% in file size.

[johnmeyer]

Originally Posted by bradwiggo

What would be the expected file size increase when interpolating from 24 to 60? Would it be 2.5 times as big, as there are 2.5 times as many frames, or would it be even bigger? As at the moment I have a 3.1 times increase in file size.

The only thing that determines file size is bitrate. Neither frame rate nor resolution has anything to do with it.

People get confused, however, because some video encoders have a "CQ" (Constant Quality) interface that alters the bitrate for you, "behind the curtains," without you explicitly setting it. With those encoders, the number of bits per second is increased or decreased in order to maintain the encoder's idea of a given level of quality. So, when using this type of encoder, the file size will increase as you change resolution or frame rate. However, as stated above, the only thing which determines file size is bitrate.

BTW, even with these encoders, increasing the frame rate may or may not change the file size much. The reason for this is that as you increase the frame rate there are certainly more frames to encode, but with almost all delivery video codecs, the video is encoded by encoding the differences between most frames. Since the differences decrease as the frame rate increases, the information needed to store the differences becomes smaller. I've already mentioned a similar thing about motion estimation, namely that it does a better and better job, the higher the frame rate you use, because it doesn't have to track much movement from one frame to the next.