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libavcodec/dnxhd_parser.c

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00001 /*
00002  * DNxHD/VC-3 parser
00003  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #include "parser.h"
00028 
00029 #define DNXHD_HEADER_PREFIX 0x0000028001
00030 
00031 static int dnxhd_find_frame_end(ParseContext *pc,
00032                                 const uint8_t *buf, int buf_size)
00033 {
00034     uint64_t state = pc->state64;
00035     int pic_found = pc->frame_start_found;
00036     int i = 0;
00037 
00038     if (!pic_found) {
00039         for (i = 0; i < buf_size; i++) {
00040             state = (state<<8) | buf[i];
00041             if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
00042                 i++;
00043                 pic_found = 1;
00044                 break;
00045             }
00046         }
00047     }
00048 
00049     if (pic_found) {
00050         if (!buf_size) /* EOF considered as end of frame */
00051             return 0;
00052         for (; i < buf_size; i++) {
00053             state = (state<<8) | buf[i];
00054             if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
00055                 pc->frame_start_found = 0;
00056                 pc->state64 = -1;
00057                 return i-4;
00058             }
00059         }
00060     }
00061     pc->frame_start_found = pic_found;
00062     pc->state64 = state;
00063     return END_NOT_FOUND;
00064 }
00065 
00066 static int dnxhd_parse(AVCodecParserContext *s,
00067                        AVCodecContext *avctx,
00068                        const uint8_t **poutbuf, int *poutbuf_size,
00069                        const uint8_t *buf, int buf_size)
00070 {
00071     ParseContext *pc = s->priv_data;
00072     int next;
00073 
00074     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
00075         next = buf_size;
00076     } else {
00077         next = dnxhd_find_frame_end(pc, buf, buf_size);
00078         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
00079             *poutbuf = NULL;
00080             *poutbuf_size = 0;
00081             return buf_size;
00082         }
00083     }
00084     *poutbuf = buf;
00085     *poutbuf_size = buf_size;
00086     return next;
00087 }
00088 
00089 AVCodecParser dnxhd_parser = {
00090     { CODEC_ID_DNXHD },
00091     sizeof(ParseContext),
00092     NULL,
00093     dnxhd_parse,
00094     ff_parse_close,
00095 };

Generated on Fri Sep 16 2011 17:17:35 for FFmpeg by  doxygen 1.7.1