gusucode.com > 一个可以在局域网进行视频聊天的源代码 > 一个可以在局域网进行视频聊天的源代码/VoIP/encoder/quant.cpp
//////////////////////////////////////////////////////////////////////////// // // // Project : VideoNet version 1.1. // Description : Peer to Peer Video Conferencing over the LAN. // Author : Nagareshwar Y Talekar ( nsry2002@yahoo.co.in) // Date : 15-6-2004. // // I have converted origional fast h.263 encoder library from C to C++ // so that it can be integrated into any windows application easily. // I have removed some of unnecessary codes/files from the // fast h263 library.Also moved definitions and declarations // in their proper .h and .cpp files. // // File description : // Name : quant.cpp // // ///////////////////////////////////////////////////////////////////////////// /************************************************* * libr263: fast H.263 encoder library * * Copyright (C) 1996, Roalt Aalmoes, Twente University * SPA multimedia group * * Based on Telenor TMN 1.6 encoder (Copyright (C) 1995, Telenor R&D) * created by Karl Lillevold * * Author encoder: Roalt Aalmoes, <aalmoes@huygens.nl> * * Date: 31-07-96 **************************************************/ #include "quant.h" /* For q=8, a "speedy" version is integrated */ int QuantAndFindCBP(int *coeff, int *qcoeff, int QP, int Mode, int CBP_Mask) { int i; int level; int tempje; int CBP = 0; if (Mode == MODE_INTRA) { /* Intra */ qcoeff[0] = mmax(1,mmin(254,coeff[0] >> 3)); /* was: /8 */ if(QP == 8) { for(i = 1; i < 64; i++) { level = (abs(coeff[i])) >> 4; qcoeff[i] = mmin(127, mmax(-127,sign(coeff[i]) * level)); if(qcoeff[i]) CBP = CBP_Mask; } } else { /* QP != 8 */ for(i = 1; i < 64; i++) { level = (abs(coeff[i])) / (2*QP); qcoeff[i] = mmin(127,mmax(-127,sign(coeff[i]) * level)); if(qcoeff[i]) CBP = CBP_Mask; } } /* End QP == 8 */ } else { /* non Intra */ if(QP == 8) { for(i = 0; i < 64; i++) { tempje = abs(coeff[i]) - 4; if(tempje < 0) { *(qcoeff++) = 0; } else { level = tempje >> 4; /* Note 2*QP == 2*8 = 2^4 == ">>4" */ if((*(qcoeff++) = mmin(127,mmax(-127,(sign(coeff[i]) > 0) ? level : -level))) != 0) CBP = CBP_Mask; } } } else { /* QP != 8 */ for (i = 0; i < 64; i++) { level = (abs(coeff[i])-QP/2) / (2*QP); if((*(qcoeff++) = mmin(127,mmax(-127,sign(coeff[i]) * level)))!= 0) CBP = CBP_Mask; } } /* End QP == 8 */ } return CBP; } void Dequant(int *qcoeff, int *rcoeff, int QP, int Mode) { int i; if (QP) { for (i = 0; i < 64; i++) { if (qcoeff[i]) { if ((QP % 2) == 1) rcoeff[i] = QP * (2*abs(qcoeff[i]) + 1); else rcoeff[i] = QP * (2*abs(qcoeff[i]) + 1) - 1; rcoeff[i] = sign(qcoeff[i]) * rcoeff[i]; } else rcoeff[i] = 0; } if (Mode == MODE_INTRA) { /* Intra */ rcoeff[0] = qcoeff[0]*8; } } else { /* No quantizing at all */ for (i = 0; i < 64; i++) { rcoeff[i] = qcoeff[i]; } } return; }