1 /* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 12 #include <stdlib.h> 13 #include "blockd.h" 14 15 16 void vp8_predict_dc(short *lastdc, short *thisdc, short quant, short *cons) 17 { 18 int diff; 19 int sign; 20 int last_dc = *lastdc; 21 int this_dc = *thisdc; 22 23 if (*cons > DCPREDCNTTHRESH) 24 { 25 this_dc += last_dc; 26 } 27 28 diff = abs(last_dc - this_dc); 29 sign = (last_dc >> 31) ^(this_dc >> 31); 30 sign |= (!last_dc | !this_dc); 31 32 if (sign) 33 { 34 *cons = 0; 35 } 36 else 37 { 38 if (diff <= DCPREDSIMTHRESH * quant) 39 (*cons)++ ; 40 } 41 42 *thisdc = this_dc; 43 *lastdc = this_dc; 44 } 45
