static void change_qscale(MpegEncContext * s, int dquant) { s->qscale += dquant; if (s->qscale < 1) s->qscale = 1; else if (s->qscale > 31) s->qscale = 31; s->y_dc_scale= s->y_dc_scale_table[ s->qscale ]; s->c_dc_scale= s->c_dc_scale_table[ s->qscale ]; }