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  1. /*
  2.  * DPX parser
  3.  * Copyright (c) 2013 Paul B Mahol
  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.  
  22. /**
  23.  * @file
  24.  * DPX parser
  25.  */
  26.  
  27. #include "libavutil/bswap.h"
  28. #include "libavutil/common.h"
  29.  
  30. #include "parser.h"
  31.  
  32. typedef struct DPXParseContext {
  33.     ParseContext pc;
  34.     uint32_t index;
  35.     uint32_t fsize;
  36.     uint32_t remaining_size;
  37.     int is_be;
  38. } DPXParseContext;
  39.  
  40. static int dpx_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  41.                      const uint8_t **poutbuf, int *poutbuf_size,
  42.                      const uint8_t *buf, int buf_size)
  43. {
  44.     DPXParseContext *d = s->priv_data;
  45.     uint32_t state = d->pc.state;
  46.     int next = END_NOT_FOUND;
  47.     int i = 0;
  48.  
  49.     s->pict_type = AV_PICTURE_TYPE_I;
  50.  
  51.     *poutbuf_size = 0;
  52.     if (buf_size == 0)
  53.         next = 0;
  54.  
  55.     if (!d->pc.frame_start_found) {
  56.         for (; i < buf_size; i++) {
  57.             state = (state << 8) | buf[i];
  58.             if (state == MKBETAG('S','D','P','X') ||
  59.                 state == MKTAG('S','D','P','X')) {
  60.                 d->pc.frame_start_found = 1;
  61.                 d->is_be = state == MKBETAG('S','D','P','X');
  62.                 d->index = 0;
  63.                 break;
  64.             }
  65.         }
  66.         d->pc.state = state;
  67.     } else {
  68.         if (d->remaining_size) {
  69.             i = FFMIN(d->remaining_size, buf_size);
  70.             d->remaining_size -= i;
  71.             if (d->remaining_size)
  72.                 goto flush;
  73.         }
  74.     }
  75.  
  76.     for (; d->pc.frame_start_found && i < buf_size; i++) {
  77.         d->pc.state = (d->pc.state << 8) | buf[i];
  78.         d->index++;
  79.         if (d->index == 17) {
  80.             d->fsize = d->is_be ? d->pc.state : av_bswap32(d->pc.state);
  81.             if (d->fsize <= 1664) {
  82.                 d->pc.frame_start_found = 0;
  83.                 goto flush;
  84.             }
  85.             if (d->fsize > buf_size - i + 19)
  86.                 d->remaining_size = d->fsize - buf_size + i - 19;
  87.             else
  88.                 i += d->fsize - 19;
  89.  
  90.             break;
  91.         } else if (d->index > 17) {
  92.             if (d->pc.state == MKBETAG('S','D','P','X') ||
  93.                 d->pc.state == MKTAG('S','D','P','X')) {
  94.                 next = i - 3;
  95.                 break;
  96.             }
  97.         }
  98.     }
  99.  
  100. flush:
  101.     if (ff_combine_frame(&d->pc, next, &buf, &buf_size) < 0)
  102.         return buf_size;
  103.  
  104.     d->pc.frame_start_found = 0;
  105.  
  106.     *poutbuf      = buf;
  107.     *poutbuf_size = buf_size;
  108.     return next;
  109. }
  110.  
  111. AVCodecParser ff_dpx_parser = {
  112.     .codec_ids      = { AV_CODEC_ID_DPX },
  113.     .priv_data_size = sizeof(DPXParseContext),
  114.     .parser_parse   = dpx_parse,
  115.     .parser_close   = ff_parse_close,
  116. };
  117.