/*
  * MPEG4 decoder / encoder common code.
  * Copyright (c) 2000,2001 Fabrice Bellard
  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "mpegvideo.h"
 #include "mpeg4video.h"
 #include "mpeg4data.h"
 
 uint8_t ff_mpeg4_static_rl_table_store[3][2][2*MAX_RUN + MAX_LEVEL + 3];
 
 int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s){
     switch(s->pict_type){

         case AV_PICTURE_TYPE_I:

             return 16;

         case AV_PICTURE_TYPE_P:
         case AV_PICTURE_TYPE_S:

             return s->f_code+15;

         case AV_PICTURE_TYPE_B:

             return FFMAX3(s->f_code, s->b_code, 2) + 15;
         default:
             return -1;
     }
 }
 
 void ff_mpeg4_clean_buffers(MpegEncContext *s)
 {
     int c_wrap, c_xy, l_wrap, l_xy;
 
     l_wrap= s->b8_stride;
     l_xy= (2*s->mb_y-1)*l_wrap + s->mb_x*2 - 1;
     c_wrap= s->mb_stride;
     c_xy= (s->mb_y-1)*c_wrap + s->mb_x - 1;
 
 #if 0
     /* clean DC */
     memsetw(s->dc_val[0] + l_xy, 1024, l_wrap*2+1);
     memsetw(s->dc_val[1] + c_xy, 1024, c_wrap+1);
     memsetw(s->dc_val[2] + c_xy, 1024, c_wrap+1);
 #endif
 
     /* clean AC */
     memset(s->ac_val[0] + l_xy, 0, (l_wrap*2+1)*16*sizeof(int16_t));
     memset(s->ac_val[1] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
     memset(s->ac_val[2] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
 
     /* clean MV */
     // we can't clear the MVs as they might be needed by a b frame
 //    memset(s->motion_val + l_xy, 0, (l_wrap*2+1)*2*sizeof(int16_t));
 //    memset(s->motion_val, 0, 2*sizeof(int16_t)*(2 + s->mb_width*2)*(2 + s->mb_height*2));
     s->last_mv[0][0][0]=
     s->last_mv[0][0][1]=
     s->last_mv[1][0][0]=
     s->last_mv[1][0][1]= 0;
 }

 
 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
 #define tab_bias (tab_size/2)
 
 //used by mpeg4 and rv10 decoder
 void ff_mpeg4_init_direct_mv(MpegEncContext *s){
     int i;
     for(i=0; i<tab_size; i++){
         s->direct_scale_mv[0][i] = (i-tab_bias)*s->pb_time/s->pp_time;
         s->direct_scale_mv[1][i] = (i-tab_bias)*(s->pb_time-s->pp_time)/s->pp_time;
     }
 }
 
 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx, int my, int i){
     int xy= s->block_index[i];
     uint16_t time_pp= s->pp_time;
     uint16_t time_pb= s->pb_time;
     int p_mx, p_my;
 

     p_mx = s->next_picture.f.motion_val[0][xy][0];

     if((unsigned)(p_mx + tab_bias) < tab_size){
         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
                             : s->direct_scale_mv[1][p_mx + tab_bias];
     }else{
         s->mv[0][i][0] = p_mx*time_pb/time_pp + mx;
         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
                             : p_mx*(time_pb - time_pp)/time_pp;
     }

     p_my = s->next_picture.f.motion_val[0][xy][1];

     if((unsigned)(p_my + tab_bias) < tab_size){
         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
                             : s->direct_scale_mv[1][p_my + tab_bias];
     }else{
         s->mv[0][i][1] = p_my*time_pb/time_pp + my;
         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
                             : p_my*(time_pb - time_pp)/time_pp;
     }
 }
 
 #undef tab_size
 #undef tab_bias
 
 /**
  *
  * @return the mb_type
  */
 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my){
     const int mb_index= s->mb_x + s->mb_y*s->mb_stride;

     const int colocated_mb_type = s->next_picture.f.mb_type[mb_index];

     uint16_t time_pp;
     uint16_t time_pb;
     int i;
 
     //FIXME avoid divides
     // try special case with shifts for 1 and 3 B-frames?
 
     if(IS_8X8(colocated_mb_type)){
         s->mv_type = MV_TYPE_8X8;
         for(i=0; i<4; i++){
             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
         }
         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
     } else if(IS_INTERLACED(colocated_mb_type)){
         s->mv_type = MV_TYPE_FIELD;
         for(i=0; i<2; i++){

             int field_select = s->next_picture.f.ref_index[0][4 * mb_index + 2 * i];

             s->field_select[0][i]= field_select;
             s->field_select[1][i]= i;
             if(s->top_field_first){
                 time_pp= s->pp_field_time - field_select + i;
                 time_pb= s->pb_field_time - field_select + i;
             }else{
                 time_pp= s->pp_field_time + field_select - i;
                 time_pb= s->pb_field_time + field_select - i;
             }
             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0]*time_pb/time_pp + mx;
             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1]*time_pb/time_pp + my;
             s->mv[1][i][0] = mx ? s->mv[0][i][0] - s->p_field_mv_table[i][0][mb_index][0]
                                 : s->p_field_mv_table[i][0][mb_index][0]*(time_pb - time_pp)/time_pp;
             s->mv[1][i][1] = my ? s->mv[0][i][1] - s->p_field_mv_table[i][0][mb_index][1]
                                 : s->p_field_mv_table[i][0][mb_index][1]*(time_pb - time_pp)/time_pp;
         }
         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 | MB_TYPE_L0L1 | MB_TYPE_INTERLACED;
     }else{
         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
         s->mv[0][1][0] = s->mv[0][2][0] = s->mv[0][3][0] = s->mv[0][0][0];
         s->mv[0][1][1] = s->mv[0][2][1] = s->mv[0][3][1] = s->mv[0][0][1];
         s->mv[1][1][0] = s->mv[1][2][0] = s->mv[1][3][0] = s->mv[1][0][0];
         s->mv[1][1][1] = s->mv[1][2][1] = s->mv[1][3][1] = s->mv[1][0][1];
         if((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) || !s->quarter_sample)
             s->mv_type= MV_TYPE_16X16;
         else
             s->mv_type= MV_TYPE_8X8;
         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1; //Note see prev line
     }
 }