/*
  * H.263i decoder
  *
  * 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 "h263.h"

 
 /* don't understand why they choose a different header ! */
 int ff_intel_h263_decode_picture_header(MpegEncContext *s)
 {
     int format;
 
     /* picture header */
     if (get_bits_long(&s->gb, 22) != 0x20) {
         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
         return -1;
     }
     s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
 
     if (get_bits1(&s->gb) != 1) {
         av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
         return -1;      /* marker */
     }
     if (get_bits1(&s->gb) != 0) {
         av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
         return -1;      /* h263 id */
     }
     skip_bits1(&s->gb);         /* split screen off */
     skip_bits1(&s->gb);         /* camera  off */
     skip_bits1(&s->gb);         /* freeze picture release off */
 
     format = get_bits(&s->gb, 3);

     if (format == 0 || format == 6) {

         av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");
         return -1;
     }
     s->h263_plus = 0;
 

     s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);

 
     s->unrestricted_mv = get_bits1(&s->gb);
     s->h263_long_vectors = s->unrestricted_mv;
 
     if (get_bits1(&s->gb) != 0) {
         av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
         return -1;      /* SAC: off */
     }
     s->obmc= get_bits1(&s->gb);
     s->pb_frame = get_bits1(&s->gb);
 

     if (format < 6) {

         s->width = ff_h263_format[format][0];
         s->height = ff_h263_format[format][1];

         s->avctx->sample_aspect_ratio.num = 12;
         s->avctx->sample_aspect_ratio.den = 11;

     } else {

         format = get_bits(&s->gb, 3);
         if(format == 0 || format == 7){
             av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");
             return -1;
         }
         if(get_bits(&s->gb, 2))
             av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
         s->loop_filter = get_bits1(&s->gb);
         if(get_bits1(&s->gb))
             av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
         if(get_bits1(&s->gb))
             s->pb_frame = 2;
         if(get_bits(&s->gb, 5))
             av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
         if(get_bits(&s->gb, 5) != 1)
             av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
     }
     if(format == 6){
         int ar = get_bits(&s->gb, 4);
         skip_bits(&s->gb, 9); // display width
         skip_bits1(&s->gb);
         skip_bits(&s->gb, 9); // display height
         if(ar == 15){

             s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
             s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height

         } else {

             s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
         }

         if (s->avctx->sample_aspect_ratio.num == 0)
             av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");

     }
 
     s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
     skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
 
     if(s->pb_frame){
         skip_bits(&s->gb, 3); //temporal reference for B-frame
         skip_bits(&s->gb, 2); //dbquant
     }
 
     /* PEI */
     while (get_bits1(&s->gb) != 0) {
         skip_bits(&s->gb, 8);
     }
     s->f_code = 1;
 
     s->y_dc_scale_table=
     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
 

     ff_h263_show_pict_info(s);

 
     return 0;
 }
 

 AVCodec ff_h263i_decoder = {

     .name           = "h263i",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_H263I,
     .priv_data_size = sizeof(MpegEncContext),
     .init           = ff_h263_decode_init,
     .close          = ff_h263_decode_end,
     .decode         = ff_h263_decode_frame,
     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("Intel H.263"),
     .pix_fmts       = ff_pixfmt_list_420,

 };