aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/assdec.c
blob: ccbf4c00cd6d2bc081bde042d0e722a28a0641de (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
/*
 * SSA/ASS demuxer
 * Copyright (c) 2008 Michael Niedermayer
 * Copyright (c) 2014 Clément Bœsch
 *
 * 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 <stdint.h>

#include "avformat.h"
#include "internal.h"
#include "subtitles.h"
#include "libavcodec/internal.h"
#include "libavutil/bprint.h"

typedef struct ASSContext {
    FFDemuxSubtitlesQueue q;
    unsigned readorder;
} ASSContext;

static int ass_probe(AVProbeData *p)
{
    char buf[13];
    FFTextReader tr;
    ff_text_init_buf(&tr, p->buf, p->buf_size);

    ff_text_read(&tr, buf, sizeof(buf));

    if (!memcmp(buf, "[Script Info]", 13))
        return AVPROBE_SCORE_MAX;

    return 0;
}

static int ass_read_close(AVFormatContext *s)
{
    ASSContext *ass = s->priv_data;
    ff_subtitles_queue_clean(&ass->q);
    return 0;
}

static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
                         int64_t *start, int *duration)
{
    int pos = 0;
    int64_t end;
    int hh1, mm1, ss1, ms1;
    int hh2, mm2, ss2, ms2;

    if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
               &hh1, &mm1, &ss1, &ms1,
               &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {

        /* This is not part of the sscanf itself in order to handle an actual
         * number (which would be the Layer) or the form "Marked=N" (which is
         * the old SSA field, now replaced by Layer, and will lead to Layer
         * being 0 here). */
        const int layer = atoi(p + 10);

        end    = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
        *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
        *duration = end - *start;

        av_bprint_clear(dst);
        av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);

        /* right strip the buffer */
        while (dst->len > 0 &&
               dst->str[dst->len - 1] == '\r' ||
               dst->str[dst->len - 1] == '\n')
            dst->str[--dst->len] = 0;
        return 0;
    }
    return -1;
}

static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
{
    int64_t pos = ff_text_pos(tr);

    av_bprint_clear(buf);
    for (;;) {
        char c = ff_text_r8(tr);
        if (!c)
            break;
        av_bprint_chars(buf, c, 1);
        if (c == '\n')
            break;
    }
    return pos;
}

static int ass_read_header(AVFormatContext *s)
{
    ASSContext *ass = s->priv_data;
    AVBPrint header, line, rline;
    int res = 0;
    AVStream *st;
    FFTextReader tr;
    ff_text_init_avio(&tr, s->pb);

    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);
    avpriv_set_pts_info(st, 64, 1, 100);
    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
    st->codec->codec_id   = AV_CODEC_ID_ASS;

    av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
    av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);
    av_bprint_init(&rline,  0, AV_BPRINT_SIZE_UNLIMITED);

    for (;;) {
        int64_t pos = get_line(&line, &tr);
        int64_t ts_start = AV_NOPTS_VALUE;
        int duration = -1;
        AVPacket *sub;

        if (!line.str[0]) // EOF
            break;

        if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
            av_bprintf(&header, "%s", line.str);
            continue;
        }
        sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
        if (!sub) {
            res = AVERROR(ENOMEM);
            goto end;
        }
        sub->pos = pos;
        sub->pts = ts_start;
        sub->duration = duration;
    }

    res = avpriv_bprint_to_extradata(st->codec, &header);
    if (res < 0)
        goto end;

    ff_subtitles_queue_finalize(&ass->q);

end:
    av_bprint_finalize(&header, NULL);
    av_bprint_finalize(&line,   NULL);
    av_bprint_finalize(&rline,  NULL);
    return res;
}

static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    ASSContext *ass = s->priv_data;
    return ff_subtitles_queue_read_packet(&ass->q, pkt);
}

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

AVInputFormat ff_ass_demuxer = {
    .name           = "ass",
    .long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
    .priv_data_size = sizeof(ASSContext),
    .read_probe     = ass_probe,
    .read_header    = ass_read_header,
    .read_packet    = ass_read_packet,
    .read_close     = ass_read_close,
    .read_seek2     = ass_read_seek,
};