I think these options directly map to the flags of the "swscale" library, i.e. the software scaling library used by FFmpeg:
from
swscale.h:
Code:
//internal chrominance subsampling info
#define SWS_FULL_CHR_H_INT 0x2000
//input subsampling info
#define SWS_FULL_CHR_H_INP 0x4000
To my understanding, this is about
chroma subsampling. So, the SWS_FULL_CHR_H_INP flag would indicate that the
input has "full" chroma resolution (YUV 4:4:4), whereas the absence of the flag would indicate chroma sub-sampling (e.g. YUV 4:2:2 or YUV 4:2:0). At the same time, the SWS_FULL_CHR_H_INT seems to indicate the chroma resolution that libswscale uses
internally.