Quantization parameter is the denominator of element-wise division. http://en.wikipedia.org/wiki/Quantization_%28image_processing%29#Quantization_matrices. So increasing QP will increase a number of lost bits of information about a picture and therefore lower image quality.
2013/9/2 theateist84 <[email protected]>: > Maybe my questions doesn't make sense due to not understanding but please > explain me what I miss because I did read posts and wiki and still it's not > clear to me. > > As I understand setting low value for qmax will improve the quality by > increasing the bitrate. Maybe I didn't understood something but isn't lowing > the Q(quantization) will decrease the quantization levels and thus the > bitrate which means degradation in quality? Or in ffmpeg lowing Q means > increasing the quantization levels? If the last is true so it make sense > that lower qmax improves the quality. > > If the above is true, so increasing qmax will decrease the quantization > levels which means less bits for coding a quantization level. So, if number > of bits for a level is lower, so total bits per frame will be lower, so how > the encoder manage to get to the desired bitrate? > > > > -- > View this message in context: > http://libav-users.943685.n4.nabble.com/Why-low-qmax-value-improve-video-quality-tp4658441.html > Sent from the libav-users mailing list archive at Nabble.com. > _______________________________________________ > Libav-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/libav-user _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
