• Main Page
  • Related Pages
  • Modules
  • Data Structures
  • Files
  • File List
  • Globals

libavcodec/mpeg4video.c

Go to the documentation of this file.
00001 /*
00002  * MPEG4 decoder / encoder common code.
00003  * Copyright (c) 2000,2001 Fabrice Bellard
00004  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "mpegvideo.h"
00024 #include "mpeg4video.h"
00025 #include "mpeg4data.h"
00026 
00027 uint8_t ff_mpeg4_static_rl_table_store[3][2][2*MAX_RUN + MAX_LEVEL + 3];
00028 
00029 int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s){
00030     switch(s->pict_type){
00031         case FF_I_TYPE:
00032             return 16;
00033         case FF_P_TYPE:
00034         case FF_S_TYPE:
00035             return s->f_code+15;
00036         case FF_B_TYPE:
00037             return FFMAX3(s->f_code, s->b_code, 2) + 15;
00038         default:
00039             return -1;
00040     }
00041 }
00042 
00043 void ff_mpeg4_clean_buffers(MpegEncContext *s)
00044 {
00045     int c_wrap, c_xy, l_wrap, l_xy;
00046 
00047     l_wrap= s->b8_stride;
00048     l_xy= (2*s->mb_y-1)*l_wrap + s->mb_x*2 - 1;
00049     c_wrap= s->mb_stride;
00050     c_xy= (s->mb_y-1)*c_wrap + s->mb_x - 1;
00051 
00052 #if 0
00053     /* clean DC */
00054     memsetw(s->dc_val[0] + l_xy, 1024, l_wrap*2+1);
00055     memsetw(s->dc_val[1] + c_xy, 1024, c_wrap+1);
00056     memsetw(s->dc_val[2] + c_xy, 1024, c_wrap+1);
00057 #endif
00058 
00059     /* clean AC */
00060     memset(s->ac_val[0] + l_xy, 0, (l_wrap*2+1)*16*sizeof(int16_t));
00061     memset(s->ac_val[1] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
00062     memset(s->ac_val[2] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
00063 
00064     /* clean MV */
00065     // we can't clear the MVs as they might be needed by a b frame
00066 //    memset(s->motion_val + l_xy, 0, (l_wrap*2+1)*2*sizeof(int16_t));
00067 //    memset(s->motion_val, 0, 2*sizeof(int16_t)*(2 + s->mb_width*2)*(2 + s->mb_height*2));
00068     s->last_mv[0][0][0]=
00069     s->last_mv[0][0][1]=
00070     s->last_mv[1][0][0]=
00071     s->last_mv[1][0][1]= 0;
00072 }
00073 
00074 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
00075 #define tab_bias (tab_size/2)
00076 
00077 //used by mpeg4 and rv10 decoder
00078 void ff_mpeg4_init_direct_mv(MpegEncContext *s){
00079     int i;
00080     for(i=0; i<tab_size; i++){
00081         s->direct_scale_mv[0][i] = (i-tab_bias)*s->pb_time/s->pp_time;
00082         s->direct_scale_mv[1][i] = (i-tab_bias)*(s->pb_time-s->pp_time)/s->pp_time;
00083     }
00084 }
00085 
00086 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx, int my, int i){
00087     int xy= s->block_index[i];
00088     uint16_t time_pp= s->pp_time;
00089     uint16_t time_pb= s->pb_time;
00090     int p_mx, p_my;
00091 
00092     p_mx= s->next_picture.motion_val[0][xy][0];
00093     if((unsigned)(p_mx + tab_bias) < tab_size){
00094         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
00095         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
00096                             : s->direct_scale_mv[1][p_mx + tab_bias];
00097     }else{
00098         s->mv[0][i][0] = p_mx*time_pb/time_pp + mx;
00099         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
00100                             : p_mx*(time_pb - time_pp)/time_pp;
00101     }
00102     p_my= s->next_picture.motion_val[0][xy][1];
00103     if((unsigned)(p_my + tab_bias) < tab_size){
00104         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
00105         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
00106                             : s->direct_scale_mv[1][p_my + tab_bias];
00107     }else{
00108         s->mv[0][i][1] = p_my*time_pb/time_pp + my;
00109         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
00110                             : p_my*(time_pb - time_pp)/time_pp;
00111     }
00112 }
00113 
00114 #undef tab_size
00115 #undef tab_bias
00116 
00121 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my){
00122     const int mb_index= s->mb_x + s->mb_y*s->mb_stride;
00123     const int colocated_mb_type= s->next_picture.mb_type[mb_index];
00124     uint16_t time_pp;
00125     uint16_t time_pb;
00126     int i;
00127 
00128     //FIXME avoid divides
00129     // try special case with shifts for 1 and 3 B-frames?
00130 
00131     if(IS_8X8(colocated_mb_type)){
00132         s->mv_type = MV_TYPE_8X8;
00133         for(i=0; i<4; i++){
00134             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
00135         }
00136         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
00137     } else if(IS_INTERLACED(colocated_mb_type)){
00138         s->mv_type = MV_TYPE_FIELD;
00139         for(i=0; i<2; i++){
00140             int field_select= s->next_picture.ref_index[0][4*mb_index + 2*i];
00141             s->field_select[0][i]= field_select;
00142             s->field_select[1][i]= i;
00143             if(s->top_field_first){
00144                 time_pp= s->pp_field_time - field_select + i;
00145                 time_pb= s->pb_field_time - field_select + i;
00146             }else{
00147                 time_pp= s->pp_field_time + field_select - i;
00148                 time_pb= s->pb_field_time + field_select - i;
00149             }
00150             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0]*time_pb/time_pp + mx;
00151             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1]*time_pb/time_pp + my;
00152             s->mv[1][i][0] = mx ? s->mv[0][i][0] - s->p_field_mv_table[i][0][mb_index][0]
00153                                 : s->p_field_mv_table[i][0][mb_index][0]*(time_pb - time_pp)/time_pp;
00154             s->mv[1][i][1] = my ? s->mv[0][i][1] - s->p_field_mv_table[i][0][mb_index][1]
00155                                 : s->p_field_mv_table[i][0][mb_index][1]*(time_pb - time_pp)/time_pp;
00156         }
00157         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 | MB_TYPE_L0L1 | MB_TYPE_INTERLACED;
00158     }else{
00159         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
00160         s->mv[0][1][0] = s->mv[0][2][0] = s->mv[0][3][0] = s->mv[0][0][0];
00161         s->mv[0][1][1] = s->mv[0][2][1] = s->mv[0][3][1] = s->mv[0][0][1];
00162         s->mv[1][1][0] = s->mv[1][2][0] = s->mv[1][3][0] = s->mv[1][0][0];
00163         s->mv[1][1][1] = s->mv[1][2][1] = s->mv[1][3][1] = s->mv[1][0][1];
00164         if((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) || !s->quarter_sample)
00165             s->mv_type= MV_TYPE_16X16;
00166         else
00167             s->mv_type= MV_TYPE_8X8;
00168         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1; //Note see prev line
00169     }
00170 }
00171 

Generated on Fri Sep 16 2011 17:17:40 for FFmpeg by  doxygen 1.7.1