[FFmpeg-user] ffmpeg Changing Video Levels

[Chris]

Is there a way for ffmpeg to encode video without altering the video levels?
I know about full- (0 - 255) and limited- (16 - 235) range video. I am working on a C program to modify video levels, using ffmpeg to read video frames into my program and to write them out. No matter what I do, ffmpeg modifies the output video levels to either 16 - 235 or 0 - 255 and this defeats what I'm trying to do. Is there any way to defeat this behavior in ffmpeg?

Ideally I would like to have an encoded video file with levels in a range other than 16 -235 or 0 - 255.
Thank you.