aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/microdvddec.c
blob: 001f1cec1583032b8d86e03afa5677c3ad984337 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/*
 * MicroDVD subtitle demuxer
 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
 * Copyright (c) 2012  Clément Bœsch <u pkh me>
 *
 * 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 "demux.h"
#include "internal.h"
#include "subtitles.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"

#define MAX_LINESIZE 2048


typedef struct {
    const AVClass *class;
    FFDemuxSubtitlesQueue q;
    AVRational frame_rate;
} MicroDVDContext;


static int microdvd_probe(const AVProbeData *p)
{
    unsigned char c;
    const uint8_t *ptr = p->buf;
    int i;

    if (AV_RB24(ptr) == 0xEFBBBF)
        ptr += 3;  /* skip UTF-8 BOM */

    for (i=0; i<3; i++) {
        if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
            sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
            sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
            return 0;
        ptr += ff_subtitles_next_line(ptr);
    }
    return AVPROBE_SCORE_MAX;
}

static int64_t get_pts(const char *buf)
{
    int frame;
    char c;

    if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
        return frame;
    return AV_NOPTS_VALUE;
}

static int64_t get_duration(const char *buf)
{
    int frame_start, frame_end;

    if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
        return frame_end - (int64_t)frame_start;
    return -1;
}

static const char *bom = "\xEF\xBB\xBF";

static int microdvd_read_header(AVFormatContext *s)
{
    AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */
    MicroDVDContext *microdvd = s->priv_data;
    AVStream *st = avformat_new_stream(s, NULL);
    int i = 0, ret;
    char line_buf[MAX_LINESIZE];
    int has_real_fps = 0;

    if (!st)
        return AVERROR(ENOMEM);

    while (!avio_feof(s->pb)) {
        char *p;
        AVPacket *sub;
        int64_t pos = avio_tell(s->pb);
        int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
        char *line = line_buf;
        int64_t pts;

        if (!strncmp(line, bom, 3))
            line += 3;
        p = line;

        if (!len)
            break;
        line[strcspn(line, "\r\n")] = 0;
        if (!*p)
            continue;
        if (i++ < 3) {
            int frame;
            double fps;
            char c;

            if ((sscanf(line, "{%d}{}%6lf",    &frame, &fps) == 2 ||
                 sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
                && frame <= 1 && fps > 3 && fps < 100) {
                pts_info = av_d2q(fps, 100000);
                has_real_fps = 1;
                continue;
            }
            if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
                int size = strlen(line + 11);
                ret = ff_alloc_extradata(st->codecpar, size);
                if (ret < 0)
                    return ret;
                memcpy(st->codecpar->extradata, line + 11, size);
                continue;
            }
        }
#define SKIP_FRAME_ID                                       \
    p = strchr(p, '}');                                     \
    if (!p) {                                               \
        av_log(s, AV_LOG_WARNING, "Invalid event \"%s\""    \
               " at line %d\n", line, i);                   \
        continue;                                           \
    }                                                       \
    p++
        SKIP_FRAME_ID;
        SKIP_FRAME_ID;
        if (!*p)
            continue;
        pts = get_pts(line);
        if (pts == AV_NOPTS_VALUE)
            continue;
        sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
        if (!sub)
            return AVERROR(ENOMEM);
        sub->pos = pos;
        sub->pts = pts;
        sub->duration = get_duration(line);
    }
    ff_subtitles_queue_finalize(s, &microdvd->q);
    if (has_real_fps) {
        /* export the FPS info only if set in the file */
        microdvd->frame_rate = pts_info;
    } else if (microdvd->frame_rate.num) {
        /* fallback on user specified frame rate */
        pts_info = microdvd->frame_rate;
    }
    avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
    st->codecpar->codec_id   = AV_CODEC_ID_MICRODVD;
    return 0;
}

static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    MicroDVDContext *microdvd = s->priv_data;
    return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
}

static int microdvd_read_seek(AVFormatContext *s, int stream_index,
                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
    MicroDVDContext *microdvd = s->priv_data;
    return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
                                   min_ts, ts, max_ts, flags);
}

static int microdvd_read_close(AVFormatContext *s)
{
    MicroDVDContext *microdvd = s->priv_data;
    ff_subtitles_queue_clean(&microdvd->q);
    return 0;
}


#define OFFSET(x) offsetof(MicroDVDContext, x)
#define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
static const AVOption microdvd_options[] = {
    { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
    { NULL }
};

static const AVClass microdvd_class = {
    .class_name = "microdvddec",
    .item_name  = av_default_item_name,
    .option     = microdvd_options,
    .version    = LIBAVUTIL_VERSION_INT,
};

const FFInputFormat ff_microdvd_demuxer = {
    .p.name         = "microdvd",
    .p.long_name    = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
    .p.priv_class   = &microdvd_class,
    .priv_data_size = sizeof(MicroDVDContext),
    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
    .read_probe     = microdvd_probe,
    .read_header    = microdvd_read_header,
    .read_packet    = microdvd_read_packet,
    .read_seek2     = microdvd_read_seek,
    .read_close     = microdvd_read_close,
};