PeerStreamer

/*

 * SubRip subtitle demuxer

 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * 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.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * 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

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "avformat.h"

#include "internal.h"

#include "libavutil/intreadwrite.h"

static int srt_probe(AVProbeData *p)

{

    unsigned char *ptr = p->buf;

    int i, v, num = 0;

    if (AV_RB24(ptr) == 0xEFBBBF)

        ptr += 3;  /* skip UTF-8 BOM */

    for (i=0; i<2; i++) {

        if (num == i && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)

            return AVPROBE_SCORE_MAX;

        num = atoi(ptr);

        ptr += strcspn(ptr, "\n") + 1;

    }

    return 0;

}

static int srt_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    AVStream *st = av_new_stream(s, 0);

    if (!st)

        return -1;

    av_set_pts_info(st, 64, 1, 1000);

    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

    st->codec->codec_id   = CODEC_ID_SRT;

    return 0;

}

static int64_t get_pts(const char *buf)

{

    int i, v, hour, min, sec, hsec;

    for (i=0; i<2; i++) {

        if (sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %*d:%*2d:%*2d%*1[,.]%3d",

                   &hour, &min, &sec, &hsec, &v) == 5) {

            min += 60*hour;

            sec += 60*min;

            return sec*1000+hsec;

        }

        buf += strcspn(buf, "\n") + 1;

    }

    return AV_NOPTS_VALUE;

}

static inline int is_eol(char c)

{

    return c == '\r' || c == '\n';

}

static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    char buffer[2048], *ptr = buffer, *ptr2;

    int64_t pos = avio_tell(s->pb);

    int res = AVERROR_EOF;

    do {

        ptr2 = ptr;

        ptr += ff_get_line(s->pb, ptr, sizeof(buffer)+buffer-ptr);

    } while (!is_eol(*ptr2) && !url_feof(s->pb) && ptr-buffer<sizeof(buffer)-1);

    if (buffer[0] && !(res = av_new_packet(pkt, ptr-buffer))) {

        memcpy(pkt->data, buffer, pkt->size);

        pkt->flags |= AV_PKT_FLAG_KEY;

        pkt->pos = pos;

        pkt->pts = pkt->dts = get_pts(pkt->data);

    }

    return res;

}

AVInputFormat ff_srt_demuxer = {

    .name        = "srt",

    .long_name   = NULL_IF_CONFIG_SMALL("SubRip subtitle format"),

    .read_probe  = srt_probe,

    .read_header = srt_read_header,

    .read_packet = srt_read_packet,

    .flags       = AVFMT_GENERIC_INDEX,

};