参数含义:bframes
最大连续b帧个数
b_bias:B帧插入强度,越大,b帧越多,
参数解析:
OPT("b-bias")
p->i_bframe_bias = atoi(value);//B帧强度
OPT("bframes")
p->i_bframe = atoi(value);
代码逻辑:
i_score = fenc->i_cost_est[b-p0][p1-b];
if( b != p1 )
i_score = (uint64_t)i_score * 100 / (120 + h->param.i_bframe_bias);//如果是B帧,相当于cost要打折
if( pict_type != 'b' )
rce->kept_as_ref = 1;
switch( pict_type )
{
case 'I':
rce->frame_type = X264_TYPE_IDR;
rce->pict_type = SLICE_TYPE_I;
break;
case 'i':
rce->frame_type = X264_TYPE_I;
rce->pict_type = SLICE_TYPE_I;
break;
case 'P':
rce->frame_type = X264_TYPE_P;
rce->pict_type = SLICE_TYPE_P;
break;
case 'B':
rce->frame_type = X264_TYPE_BREF;
rce->pict_type = SLICE_TYPE_B;
break;
case 'b':
rce->frame_type = X264_TYPE_B;
rce->pict_type = SLICE_TYPE_B;
break;
default: e = -1; break;
}
x264_slicetype_path()
-->x264_slicetype_path_cost()
最大连续b帧个数
b_bias:B帧插入强度,越大,b帧越多,
参数解析:
OPT("b-bias")
p->i_bframe_bias = atoi(value);//B帧强度
OPT("bframes")
p->i_bframe = atoi(value);
代码逻辑:
i_score = fenc->i_cost_est[b-p0][p1-b];
if( b != p1 )
i_score = (uint64_t)i_score * 100 / (120 + h->param.i_bframe_bias);//如果是B帧,相当于cost要打折
if( pict_type != 'b' )
rce->kept_as_ref = 1;
switch( pict_type )
{
case 'I':
rce->frame_type = X264_TYPE_IDR;
rce->pict_type = SLICE_TYPE_I;
break;
case 'i':
rce->frame_type = X264_TYPE_I;
rce->pict_type = SLICE_TYPE_I;
break;
case 'P':
rce->frame_type = X264_TYPE_P;
rce->pict_type = SLICE_TYPE_P;
break;
case 'B':
rce->frame_type = X264_TYPE_BREF;
rce->pict_type = SLICE_TYPE_B;
break;
case 'b':
rce->frame_type = X264_TYPE_B;
rce->pict_type = SLICE_TYPE_B;
break;
default: e = -1; break;
}
x264_slicetype_path()
-->x264_slicetype_path_cost()
-->x264_slicetype_frame_cost()设置帧类型,每一帧的类型用一个字幕代替如P,I,B
b-pyramid
默认:normal
说明:允许B帧作为参照帧。如果关闭,那么只有I帧和P帧才能作为参照帧。可以作为参照帧的B帧的量化参数会介于P帧和普通B帧之间。只在–b-frames设置大于等于2时此选项才生效。如果是在为蓝光光盘编码,请使用none或者strict。
none —— 不允许B帧作为参照帧;
strict —— 一个图像组内只允许一个B帧参照帧,这是蓝光编码强制要求的标准;
normal —— 任意使用B帧参照帧;