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
  24  * DNxHD/VC-3 parser
  25  */
  26
  27 #include "parser.h"
  28 #include "dnxhddata.h"
  29 #include "parser_internal.h"
  30
  31 typedef struct {
  32     ParseContext pc;
  33     int cur_byte;
  34     int remaining;
  35     int w, h;
  36 } DNXHDParserContext;
  37
  38 static int dnxhd_find_frame_end(DNXHDParserContext *dctx,
  39                                 const uint8_t *buf, int buf_size)
  40 {
  41     ParseContext *pc = &dctx->pc;
  42     uint64_t state = pc->state64;
  43     int pic_found = pc->frame_start_found;
  44     int i = 0;
  45
  46     if (!pic_found) {
  47         for (i = 0; i < buf_size; i++) {
  48             state = (state << 8) | buf[i];
  49             if (ff_dnxhd_check_header_prefix(state & 0xffffffffff00LL) != 0) {
  50                 i++;
  51                 pic_found = 1;
  52                 dctx->cur_byte = 0;
  53                 dctx->remaining = 0;
  54                 break;
  55             }
  56         }
  57     }
  58
  59     if (pic_found && !dctx->remaining) {
  60         if (!buf_size) /* EOF considered as end of frame */
  61             return 0;
  62         for (; i < buf_size; i++) {
  63             dctx->cur_byte++;
  64             state = (state << 8) | buf[i];
  65
  66             if (dctx->cur_byte == 24) {
  67                 dctx->h = (state >> 32) & 0xFFFF;
  68             } else if (dctx->cur_byte == 26) {
  69                 dctx->w = (state >> 32) & 0xFFFF;
  70             } else if (dctx->cur_byte == 42) {
  71                 int cid = (state >> 32) & 0xFFFFFFFF;
  72                 int remaining;
  73
  74                 if (cid <= 0)
  75                     continue;
  76
  77                 remaining = ff_dnxhd_get_frame_size(cid);
  78                 if (remaining <= 0) {
  79                     remaining = ff_dnxhd_get_hr_frame_size(cid, dctx->w, dctx->h);
  80                     if (remaining <= 0)
  81                         continue;
  82                 }
  83                 remaining += i - 47;
  84                 dctx->remaining = remaining;
  85                 if (buf_size >= dctx->remaining) {
  86                     pc->frame_start_found = 0;
  87                     pc->state64 = -1;
  88                     dctx->cur_byte = 0;
  89                     dctx->remaining = 0;
  90                     return remaining;
  91                 } else {
  92                     dctx->remaining -= buf_size;
  93                     // Update variables for correctness, they are currently not used beyond here
  94                     state = -1;
  95                     dctx->cur_byte += buf_size - i;
  96                     break;
  97                 }
  98             }
  99         }
 100     } else if (pic_found) {
 101         if (dctx->remaining > buf_size) {
 102             dctx->remaining -= buf_size;
 103         } else {
 104             int remaining = dctx->remaining;
 105
 106             pc->frame_start_found = 0;
 107             pc->state64 = -1;
 108             dctx->cur_byte = 0;
 109             dctx->remaining = 0;
 110             return remaining;
 111         }
 112     }
 113     pc->frame_start_found = pic_found;
 114     pc->state64 = state;
 115     return END_NOT_FOUND;
 116 }
 117
 118 static int dnxhd_parse(AVCodecParserContext *s,
 119                        AVCodecContext *avctx,
 120                        const uint8_t **poutbuf, int *poutbuf_size,
 121                        const uint8_t *buf, int buf_size)
 122 {
 123     DNXHDParserContext *dctx = s->priv_data;
 124     ParseContext *pc = &dctx->pc;
 125     int next;
 126
 127     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
 128         next = buf_size;
 129     } else {
 130         next = dnxhd_find_frame_end(dctx, buf, buf_size);
 131         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 132             *poutbuf      = NULL;
 133             *poutbuf_size = 0;
 134             return buf_size;
 135         }
 136     }
 137     *poutbuf      = buf;
 138     *poutbuf_size = buf_size;
 139     return next;
 140 }
 141
 142 const FFCodecParser ff_dnxhd_parser = {
 143     PARSER_CODEC_LIST(AV_CODEC_ID_DNXHD),
 144     .priv_data_size = sizeof(DNXHDParserContext),
 145     .parse          = dnxhd_parse,
 146     .close          = ff_parse_close,
 147 };