libavcodec/dvdsub_parser.c

   1 /*
   2  * DVD subtitle decoding for ffmpeg
   3  * Copyright (c) 2005 Fabrice Bellard.
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21 #include "avcodec.h"
  22
  23 /* parser definition */
  24 typedef struct DVDSubParseContext {
  25     uint8_t *packet;
  26     int packet_len;
  27     int packet_index;
  28 } DVDSubParseContext;
  29
  30 static int dvdsub_parse_init(AVCodecParserContext *s)
  31 {
  32     return 0;
  33 }
  34
  35 static int dvdsub_parse(AVCodecParserContext *s,
  36                         AVCodecContext *avctx,
  37                         const uint8_t **poutbuf, int *poutbuf_size,
  38                         const uint8_t *buf, int buf_size)
  39 {
  40     DVDSubParseContext *pc = s->priv_data;
  41
  42     if (pc->packet_index == 0) {
  43         if (buf_size < 2)
  44             return 0;
  45         pc->packet_len = AV_RB16(buf);
  46         if (pc->packet_len == 0) /* HD-DVD subpicture packet */
  47             pc->packet_len = AV_RB32(buf+2);
  48         av_freep(&pc->packet);
  49         pc->packet = av_malloc(pc->packet_len);
  50     }
  51     if (pc->packet) {
  52         if (pc->packet_index + buf_size <= pc->packet_len) {
  53             memcpy(pc->packet + pc->packet_index, buf, buf_size);
  54             pc->packet_index += buf_size;
  55             if (pc->packet_index >= pc->packet_len) {
  56                 *poutbuf = pc->packet;
  57                 *poutbuf_size = pc->packet_len;
  58                 pc->packet_index = 0;
  59                 return buf_size;
  60             }
  61         } else {
  62             /* erroneous size */
  63             pc->packet_index = 0;
  64         }
  65     }
  66     *poutbuf = NULL;
  67     *poutbuf_size = 0;
  68     return buf_size;
  69 }
  70
  71 static void dvdsub_parse_close(AVCodecParserContext *s)
  72 {
  73     DVDSubParseContext *pc = s->priv_data;
  74     av_freep(&pc->packet);
  75 }
  76
  77 AVCodecParser dvdsub_parser = {
  78     { CODEC_ID_DVD_SUBTITLE },
  79     sizeof(DVDSubParseContext),
  80     dvdsub_parse_init,
  81     dvdsub_parse,
  82     dvdsub_parse_close,
  83 };