mirror of
https://github.com/FFmpeg/FFmpeg.git
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130 lines
3.9 KiB
C
130 lines
3.9 KiB
C
/*
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* MicroDVD subtitle demuxer
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* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#include "avformat.h"
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#include "internal.h"
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#include "libavutil/intreadwrite.h"
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#define MAX_LINESIZE 2048
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typedef struct {
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uint8_t lines[3][MAX_LINESIZE];
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int64_t pos[3];
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} MicroDVDContext;
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static int microdvd_probe(AVProbeData *p)
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{
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unsigned char c, *ptr = p->buf;
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int i;
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if (AV_RB24(ptr) == 0xEFBBBF)
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ptr += 3; /* skip UTF-8 BOM */
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for (i=0; i<3; i++) {
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if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
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sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
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sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
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return 0;
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ptr += strcspn(ptr, "\n") + 1;
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}
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return AVPROBE_SCORE_MAX;
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}
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static int microdvd_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
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MicroDVDContext *microdvd = s->priv_data;
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AVStream *st = av_new_stream(s, 0);
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int i, frame;
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double fps;
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char c;
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if (!st)
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return -1;
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for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
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microdvd->pos[i] = avio_tell(s->pb);
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ff_get_line(s->pb, microdvd->lines[i], sizeof(microdvd->lines[i]));
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if ((sscanf(microdvd->lines[i], "{%d}{}%6lf", &frame, &fps) == 2 ||
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sscanf(microdvd->lines[i], "{%d}{%*d}%6lf", &frame, &fps) == 2)
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&& frame <= 1 && fps > 3 && fps < 100)
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pts_info = av_d2q(fps, 100000);
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if (sscanf(microdvd->lines[i], "{DEFAULT}{}%c", &c) == 1) {
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st->codec->extradata = av_strdup(microdvd->lines[i] + 11);
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st->codec->extradata_size = strlen(st->codec->extradata);
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i--;
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}
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}
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av_set_pts_info(st, 64, pts_info.den, pts_info.num);
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st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codec->codec_id = CODEC_ID_MICRODVD;
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return 0;
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}
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static int64_t get_pts(const char *buf)
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{
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int frame;
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char c;
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if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
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return frame;
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return AV_NOPTS_VALUE;
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}
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static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MicroDVDContext *microdvd = s->priv_data;
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char buffer[MAX_LINESIZE];
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int64_t pos = avio_tell(s->pb);
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int i, len = 0, res = AVERROR_EOF;
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for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
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if (microdvd->lines[i][0]) {
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strcpy(buffer, microdvd->lines[i]);
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pos = microdvd->pos[i];
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len = strlen(buffer);
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microdvd->lines[i][0] = 0;
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break;
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}
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}
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if (!len)
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len = ff_get_line(s->pb, buffer, sizeof(buffer));
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if (buffer[0] && !(res = av_new_packet(pkt, len))) {
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memcpy(pkt->data, buffer, len);
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pkt->flags |= AV_PKT_FLAG_KEY;
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pkt->pos = pos;
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pkt->pts = pkt->dts = get_pts(buffer);
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}
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return res;
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}
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AVInputFormat ff_microdvd_demuxer = {
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.name = "microdvd",
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.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
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.priv_data_size = sizeof(MicroDVDContext),
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.read_probe = microdvd_probe,
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.read_header = microdvd_read_header,
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.read_packet = microdvd_read_packet,
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.flags = AVFMT_GENERIC_INDEX,
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};
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