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ffmpeg / libavcodec / dnxhd_parser.c @ 2912e87a

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/*
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 * DNxHD/VC-3 parser
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 * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * DNxHD/VC-3 parser
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 */
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#include "parser.h"
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#define DNXHD_HEADER_PREFIX 0x0000028001
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static int dnxhd_find_frame_end(ParseContext *pc,
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                                const uint8_t *buf, int buf_size)
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{
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    uint64_t state = pc->state64;
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    int pic_found = pc->frame_start_found;
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    int i = 0;
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    if (!pic_found) {
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        for (i = 0; i < buf_size; i++) {
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            state = (state<<8) | buf[i];
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            if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
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                i++;
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                pic_found = 1;
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                break;
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            }
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        }
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    }
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    if (pic_found) {
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        if (!buf_size) /* EOF considered as end of frame */
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            return 0;
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        for (; i < buf_size; i++) {
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            state = (state<<8) | buf[i];
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            if ((state & 0xffffffffffLL) == DNXHD_HEADER_PREFIX) {
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                pc->frame_start_found = 0;
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                pc->state64 = -1;
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                return i-4;
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            }
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        }
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    }
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    pc->frame_start_found = pic_found;
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    pc->state64 = state;
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    return END_NOT_FOUND;
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}
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static int dnxhd_parse(AVCodecParserContext *s,
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                       AVCodecContext *avctx,
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                       const uint8_t **poutbuf, int *poutbuf_size,
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                       const uint8_t *buf, int buf_size)
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{
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    ParseContext *pc = s->priv_data;
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    int next;
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    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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        next = buf_size;
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    } else {
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        next = dnxhd_find_frame_end(pc, buf, buf_size);
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        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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            *poutbuf = NULL;
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            *poutbuf_size = 0;
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            return buf_size;
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        }
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    }
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    *poutbuf = buf;
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    *poutbuf_size = buf_size;
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    return next;
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}
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AVCodecParser ff_dnxhd_parser = {
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    { CODEC_ID_DNXHD },
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    sizeof(ParseContext),
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    NULL,
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    dnxhd_parse,
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    ff_parse_close,
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};