xref: /third_party/ffmpeg/libavformat/mpl2dec.c (revision cabdff1a)
1/*
2 * Copyright (c) 2012 Clément Bœsch
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * MPL2 subtitles format demuxer
24 */
25
26#include "libavutil/intreadwrite.h"
27
28#include "avformat.h"
29#include "internal.h"
30#include "subtitles.h"
31
32typedef struct {
33    FFDemuxSubtitlesQueue q;
34} MPL2Context;
35
36static int mpl2_probe(const AVProbeData *p)
37{
38    int i;
39    char c;
40    int64_t start, end;
41    const unsigned char *ptr = p->buf;
42    const unsigned char *ptr_end = ptr + p->buf_size;
43
44    if (AV_RB24(ptr) == 0xefbbbf)
45        ptr += 3;
46
47    for (i = 0; i < 2; i++) {
48        if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
49            sscanf(ptr, "[%"SCNd64"][]%c",          &start,       &c) != 2)
50            return 0;
51        ptr += ff_subtitles_next_line(ptr);
52        if (ptr >= ptr_end)
53            return 0;
54    }
55    return AVPROBE_SCORE_MAX;
56}
57
58static int read_ts(char **line, int64_t *pts_start, int64_t *duration)
59{
60    char c;
61    int len;
62    int64_t end;
63
64    if (sscanf(*line, "[%"SCNd64"][]%c%n",
65               pts_start, &c, &len) >= 2) {
66        *duration = -1;
67        *line += len - 1;
68        return 0;
69    }
70    if (sscanf(*line, "[%"SCNd64"][%"SCNd64"]%c%n",
71               pts_start, &end, &c, &len) >= 3) {
72        if (end < *pts_start || end - (uint64_t)*pts_start > INT64_MAX) {
73            *duration = -1;
74        } else
75            *duration = end - *pts_start;
76        *line += len - 1;
77        return 0;
78    }
79    return -1;
80}
81
82static int mpl2_read_header(AVFormatContext *s)
83{
84    MPL2Context *mpl2 = s->priv_data;
85    AVStream *st = avformat_new_stream(s, NULL);
86
87    if (!st)
88        return AVERROR(ENOMEM);
89    avpriv_set_pts_info(st, 64, 1, 10);
90    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
91    st->codecpar->codec_id   = AV_CODEC_ID_MPL2;
92
93    if (avio_rb24(s->pb) != 0xefbbbf)
94        avio_seek(s->pb, -3, SEEK_CUR);
95
96    while (!avio_feof(s->pb)) {
97        char line[4096];
98        char *p = line;
99        const int64_t pos = avio_tell(s->pb);
100        int len = ff_get_line(s->pb, line, sizeof(line));
101        int64_t pts_start;
102        int64_t duration;
103
104        if (!len)
105            break;
106
107        line[strcspn(line, "\r\n")] = 0;
108
109        if (!read_ts(&p, &pts_start, &duration)) {
110            AVPacket *sub;
111
112            sub = ff_subtitles_queue_insert(&mpl2->q, p, strlen(p), 0);
113            if (!sub)
114                return AVERROR(ENOMEM);
115            sub->pos = pos;
116            sub->pts = pts_start;
117            sub->duration = duration;
118        }
119    }
120
121    ff_subtitles_queue_finalize(s, &mpl2->q);
122    return 0;
123}
124
125const AVInputFormat ff_mpl2_demuxer = {
126    .name           = "mpl2",
127    .long_name      = NULL_IF_CONFIG_SMALL("MPL2 subtitles"),
128    .priv_data_size = sizeof(MPL2Context),
129    .flags_internal = FF_FMT_INIT_CLEANUP,
130    .read_probe     = mpl2_probe,
131    .read_header    = mpl2_read_header,
132    .extensions     = "txt,mpl2",
133    .read_packet    = ff_subtitles_read_packet,
134    .read_seek2     = ff_subtitles_read_seek,
135    .read_close     = ff_subtitles_read_close,
136};
137