x265-1.8版本-encoder/bitcost.h注释

注：问号以及未注释部分 会在x265-1.9版本内更新

/***************************************************************************** * Copyright (C) 2013 x265 project * * Authors: Steve Borho <[e-mail]> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA. * * This program is also available under a commercial proprietary license. * For more information, contact us at license @ x265.com. *****************************************************************************/#ifndef X265_BITCOST_H#define X265_BITCOST_H#include "common.h"#include "threading.h"#include "mv.h"namespace X265_NS {// private x265 namespace//BitCost主要用于计算MVD-cost MVD = MV-MVP class BitCost //被MotionEstimate继承{public:    //初始化    BitCost() : m_cost_mvx(0), m_cost_mvy(0), m_cost(0), m_mvp(0) {}    /** 函数功能             ：建立当前qp下的MVD占用的cost：λ*bits = 2^(qp/6-2) * s_bitsizes[i]    * \参数 qp               ：当前ME下的qp大小    * \返回                  ：null * */    void setQP(unsigned int qp);    /** 函数功能             ：设置当前的MVP，并更新以当前MVP的MVD-cost表格：如当前MV=（3,6）MVP=(1,2),则MVD=(2,4) 期MVcost = m_cost_mvx[mv.x] + m_cost_mvy[mv.y] = m_cost_mvx[3] + m_cost_mvy[6]                                                                                                                      = m_cost[3-1] + m_cost[6-2] = m_cost[2] + m_cost[4]    * \参数 mvp              ：设置当前ME搜索时选用的MVP，以及计算MVD cost的表格    * \返回                  ：null * */    void setMVP(const MV& mvp)                      { m_mvp = mvp; m_cost_mvx = m_cost - mvp.x; m_cost_mvy = m_cost - mvp.y; }    // return bit cost of motion vector difference, multiplied by lambda    /** 函数功能             ：返回当前MV与MVP之间的差（MVD）占用的bits-cost    * \参数 mv               ：当前待计算的MV    * \返回                  ：null * */    inline uint16_t mvcost(const MV& mv) const      { return m_cost_mvx[mv.x] + m_cost_mvy[mv.y]; }    // return bit cost of motion vector difference, without lambda    /** 函数功能             ：返回当前MV与MVP之间的差（MVD）占用的bits，没有经过λ加权    * \参数 mv               ：当前待计算的MV    * \返回                  ：null * */    inline uint32_t bitcost(const MV& mv) const    {        return (uint32_t)(s_bitsizes[abs(mv.x - m_mvp.x)] +                          s_bitsizes[abs(mv.y - m_mvp.y)] + 0.5f);    }    /** 函数功能             ：返回当前MV与MVP之间的差（MVD）占用的bits，没有经过λ加权    * \参数 mv               ：当前待计算的MV    * \参数 mvp              ：当前待计算的MVP    * \返回                  ：null * */    static inline uint32_t bitcost(const MV& mv, const MV& mvp)    {        return (uint32_t)(s_bitsizes[abs(mv.x - mvp.x)] +                          s_bitsizes[abs(mv.y - mvp.y)] + 0.5f);    }    /** 函数功能   ： 释放空间内存    * \返回        ： null */    static void destroy();protected:    uint16_t *m_cost_mvx;//计算当前MVD x坐标占用的bits-cost    uint16_t *m_cost_mvy;//计算当前MVD y坐标占用的bits-cost    uint16_t *m_cost;   //当前qp下的MVD占用的cost：λ*bits = 2^(qp/6-2) * s_bitsizes[i]，在setQP()中进行初始化    MV        m_mvp;    //当前ME搜索时选用的MVP    BitCost& operator =(const BitCost&);private:    /* default log2_max_mv_length_horizontal and log2_max_mv_length_horizontal     * are 15, specified in quarter-pel luma sample units. making the maximum     * signaled ful-pel motion distance 4096, max qpel is 32768 */    //最大整像素运动矢量为4096 1/4像素 最大为32768    enum { BC_MAX_MV = (1 << 15) };    enum { BC_MAX_QP = 82 };    static float *s_bitsizes; //申请空间大小为 2*32768+1   MVD估计占用bits表格,例如：当前MV.x = 3 ,则其占用bits 为 s_bitsizes[3] 2*(log2(3+1))+e-1    /*    s_bitsizes[0] = e - 2   s_bitsizes[i]= 2*(log2(i+1))+e-1  log2 表示以2为底    s_bitsizes[1] = 2log2(2) + e -1    **/    static uint16_t *s_costs[BC_MAX_QP];//所有的me共有，每个qp只初始化一次    static Lock s_costCalcLock;         //多线程锁    /** 函数功能             ：建立MVD估计占用bits表格,例如：当前MV.x = 3 ,则其占用bits 为 s_bitsizes[3] 2*(log2(3+1))+e-1    * \返回                  ：null * */    static void CalculateLogs();};}#endif // ifndef X265_BITCOST_H