libavcodec/dnxhd_parser.c

   1 /*
   2  * DNxHD/VC-3 parser
   3  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
   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 libavcodec/dnxhd_parser.c
  24  * DNxHD/VC-3 parser
  25  */
  26
  27 #include "parser.h"
  28
  29 #define DNXHD_HEADER_PREFIX 0x0000028001
  30
  31 static int dnxhd_find_frame_end(ParseContext *pc,
  32                                 const uint8_t *buf, int buf_size)
  33 {
  34     uint64_t state = pc->state64;
  35     int pic_found = pc->frame_start_found;
  36     int i = 0;
  37
  38     if (!pic_found) {
  39         for (i = 0; i < buf_size; i++) {
  40             state = (state<<8) | buf[i];
  41             if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
  42                 i++;
  43                 pic_found = 1;
  44                 break;
  45             }
  46         }
  47     }
  48
  49     if (pic_found) {
  50         if (!buf_size) /* EOF considered as end of frame */
  51             return 0;
  52         for (; i < buf_size; i++) {
  53             state = (state<<8) | buf[i];
  54             if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
  55                 pc->frame_start_found = 0;
  56                 pc->state64 = -1;
  57                 return i-4;
  58             }
  59         }
  60     }
  61     pc->frame_start_found = pic_found;
  62     pc->state64 = state;
  63     return END_NOT_FOUND;
  64 }
  65
  66 static int dnxhd_parse(AVCodecParserContext *s,
  67                        AVCodecContext *avctx,
  68                        const uint8_t **poutbuf, int *poutbuf_size,
  69                        const uint8_t *buf, int buf_size)
  70 {
  71     ParseContext *pc = s->priv_data;
  72     int next;
  73
  74     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
  75         next = buf_size;
  76     } else {
  77         next = dnxhd_find_frame_end(pc, buf, buf_size);
  78         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
  79             *poutbuf = NULL;
  80             *poutbuf_size = 0;
  81             return buf_size;
  82         }
  83     }
  84     *poutbuf = buf;
  85     *poutbuf_size = buf_size;
  86     return next;
  87 }
  88
  89 AVCodecParser dnxhd_parser = {
  90     { CODEC_ID_DNXHD },
  91     sizeof(ParseContext),
  92     NULL,
  93     dnxhd_parse,
  94     ff_parse_close,
  95 };