dvdsub_parser.c 2.66 KB
Newer Older
1
/*
2
 * DVD subtitle decoding
3
 * Copyright (c) 2005 Fabrice Bellard
4
 *
5
 * This file is part of Libav.
6
 *
7
 * Libav is free software; you can redistribute it and/or
8 9 10 11
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
12
 * Libav is distributed in the hope that it will be useful,
13 14 15 16 17
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * 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 20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
21

22 23
#include <string.h>

24
#include "libavutil/intreadwrite.h"
25
#include "libavutil/mem.h"
26 27 28 29 30 31 32 33 34
#include "avcodec.h"

/* parser definition */
typedef struct DVDSubParseContext {
    uint8_t *packet;
    int packet_len;
    int packet_index;
} DVDSubParseContext;

35
static av_cold int dvdsub_parse_init(AVCodecParserContext *s)
36 37 38 39 40 41
{
    return 0;
}

static int dvdsub_parse(AVCodecParserContext *s,
                        AVCodecContext *avctx,
42
                        const uint8_t **poutbuf, int *poutbuf_size,
43 44 45 46 47 48 49 50
                        const uint8_t *buf, int buf_size)
{
    DVDSubParseContext *pc = s->priv_data;

    if (pc->packet_index == 0) {
        if (buf_size < 2)
            return 0;
        pc->packet_len = AV_RB16(buf);
51 52
        if (pc->packet_len == 0) /* HD-DVD subpicture packet */
            pc->packet_len = AV_RB32(buf+2);
53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
        av_freep(&pc->packet);
        pc->packet = av_malloc(pc->packet_len);
    }
    if (pc->packet) {
        if (pc->packet_index + buf_size <= pc->packet_len) {
            memcpy(pc->packet + pc->packet_index, buf, buf_size);
            pc->packet_index += buf_size;
            if (pc->packet_index >= pc->packet_len) {
                *poutbuf = pc->packet;
                *poutbuf_size = pc->packet_len;
                pc->packet_index = 0;
                return buf_size;
            }
        } else {
            /* erroneous size */
            pc->packet_index = 0;
        }
    }
    *poutbuf = NULL;
    *poutbuf_size = 0;
    return buf_size;
}

76
static av_cold void dvdsub_parse_close(AVCodecParserContext *s)
77 78 79 80 81
{
    DVDSubParseContext *pc = s->priv_data;
    av_freep(&pc->packet);
}

82
AVCodecParser ff_dvdsub_parser = {
83
    .codec_ids      = { AV_CODEC_ID_DVD_SUBTITLE },
84 85 86 87
    .priv_data_size = sizeof(DVDSubParseContext),
    .parser_init    = dvdsub_parse_init,
    .parser_parse   = dvdsub_parse,
    .parser_close   = dvdsub_parse_close,
88
};