ffmpeg – Setting transfer characteristics for overlaying multiple videos

I just wanna know whether I can set unique values of transfer characteristics/gamma for each videos while overlaying it on top of a single video.

For example :-

FFmpeg command : ffmpeg -f lavfi -i color=c=#ffffff:s=1920×1080:d=43 -i abc.mp4 -i def.mp4 -filter_complex “[1:v]setpts=PTS+0/TB[top1]; [2:v]setpts=PTS+12.9/TB[top2];[0:v][top1]overlay=-0.75:0:enable=”between(t,0,12.9)”[outv1]; [outv1][top2]overlay=-66:0:enable=”between(t,12.9,42.9)”[outv2];” -map “[outv2]” -c:v libx264 -preset ultrafast -c:a copy -strict experimental output.mp4 -y

In this command, abc.mp4 video has a transfer characteristics value of 1 and def.mp4 has the transfer characteristics value of 7. I’m trying to overlay both videos on top of a white background. By default, the white background has transfer characteristics value as 1. So def.mp4 video’s color gets dull. How can i handle this?