libavcodec/flvdec.c

   1 /*
   2  * FLV decoding.
   3  * This file is part of Libav.
   4  *
   5  * Libav is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * Libav is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with Libav; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include "mpegvideo.h"
  21 #include "h263.h"
  22 #include "flv.h"
  23 #include "libavutil/imgutils.h"
  24
  25 void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last){
  26     int is11 = get_bits1(gb);
  27     *last = get_bits1(gb);
  28     *run = get_bits(gb, 6);
  29     if(is11){
  30         *level = get_sbits(gb, 11);
  31     } else {
  32         *level = get_sbits(gb, 7);
  33     }
  34 }
  35
  36 int ff_flv_decode_picture_header(MpegEncContext *s)
  37 {
  38     int format, width, height;
  39
  40     /* picture header */
  41     if (get_bits_long(&s->gb, 17) != 1) {
  42         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
  43         return -1;
  44     }
  45     format = get_bits(&s->gb, 5);
  46     if (format != 0 && format != 1) {
  47         av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
  48         return -1;
  49     }
  50     s->h263_flv = format+1;
  51     s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
  52     format = get_bits(&s->gb, 3);
  53     switch (format) {
  54     case 0:
  55         width = get_bits(&s->gb, 8);
  56         height = get_bits(&s->gb, 8);
  57         break;
  58     case 1:
  59         width = get_bits(&s->gb, 16);
  60         height = get_bits(&s->gb, 16);
  61         break;
  62     case 2:
  63         width = 352;
  64         height = 288;
  65         break;
  66     case 3:
  67         width = 176;
  68         height = 144;
  69         break;
  70     case 4:
  71         width = 128;
  72         height = 96;
  73         break;
  74     case 5:
  75         width = 320;
  76         height = 240;
  77         break;
  78     case 6:
  79         width = 160;
  80         height = 120;
  81         break;
  82     default:
  83         width = height = 0;
  84         break;
  85     }
  86     if(av_image_check_size(width, height, 0, s->avctx))
  87         return -1;
  88     s->width = width;
  89     s->height = height;
  90
  91     s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
  92     s->droppable = s->pict_type > AV_PICTURE_TYPE_P;
  93     if (s->droppable)
  94         s->pict_type = AV_PICTURE_TYPE_P;
  95
  96     skip_bits1(&s->gb); /* deblocking flag */
  97     s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
  98
  99     s->h263_plus = 0;
 100
 101     s->unrestricted_mv = 1;
 102     s->h263_long_vectors = 0;
 103
 104     /* PEI */
 105     while (get_bits1(&s->gb) != 0) {
 106         skip_bits(&s->gb, 8);
 107     }
 108     s->f_code = 1;
 109
 110     if(s->avctx->debug & FF_DEBUG_PICT_INFO){
 111         av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
 112                s->droppable ? 'D' : av_get_picture_type_char(s->pict_type),
 113                s->h263_flv - 1, s->qscale, s->picture_number);
 114     }
 115
 116     s->y_dc_scale_table=
 117     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
 118
 119     return 0;
 120 }
 121
 122 AVCodec ff_flv_decoder = {
 123     .name           = "flv",
 124     .type           = AVMEDIA_TYPE_VIDEO,
 125     .id             = AV_CODEC_ID_FLV1,
 126     .priv_data_size = sizeof(MpegEncContext),
 127     .init           = ff_h263_decode_init,
 128     .close          = ff_h263_decode_end,
 129     .decode         = ff_h263_decode_frame,
 130     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
 131     .long_name      = NULL_IF_CONFIG_SMALL("FLV / Sorenson Spark / Sorenson H.263 (Flash Video)"),
 132     .pix_fmts       = ff_pixfmt_list_420,
 133 };