[x265] Can we use binary search for q in clipQscale

[chen]

In the RateControl::clipQscale(),  the Q just correlation to predictSize(x, Q, y).
In here, x and y is constant, so we can use other algorithm to get estimate value of Q faster than search.


btw: below code also constant in every iteration


int type = curFrame->m_lowres.plannedType[j];
type = IS_X265_TYPE_I(type) ? I_SLICE : IS_X265_TYPE_B(type) ? B_SLICE : P_SLICE;
int predType = getPredictorType(curFrame->m_lowres.plannedType[j], type);





At 2015-10-09 17:24:14,"Ximing Cheng" <chengximing1989 at gmail.com> wrote:


In RateControl::clipQscale(Frame* curFrame, RateControlEntry* rce, double q)



for (int iterations = 0; iterations < 1000 && loopTerminate != 3; iterations++)



to find a valid q which makes the buffer at least 50% filled but no more than 80% fulled, the code use a iteration for at most 1000 times.


Is it suitable here to use binary search for q to reduce the iterations?
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