Probably some bug in ecoding AC coefficients as the reference frame calculated by FPGA seems fine: qi=25: http://www.elphel.com/downloads/fourteenth_q29.ogg http://www.elphel.com/downloads/fourteenth_q29.png qi=63 (maximal) http://www.elphel.com/downloads/fourteenth_q63.ogg http://www.elphel.com/downloads/fourteenth_q63.png