libavcodec/dpx_parser.c

   1 /*
   2  * DPX parser
   3  * Copyright (c) 2013 Paul B Mahol
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 };