s->i_quant_factor=0.8;
s->i_quant_factor=-0.8;
void avcodec_get_context_defaults(AVCodecContext *s){    s->bit_rate= 800*1000;    s->bit_rate_tolerance= s->bit_rate*10;    s->qmin= 2;    s->qmax= 31;    s->rc_eq= "tex^qComp";    s->qcompress= 0.5;    s->max_qdiff= 3;    s->b_quant_factor=1.25;    s->b_quant_offset=1.25;    s->i_quant_factor=0.8;    s->i_quant_offset=0.0;}