summaryrefslogtreecommitdiff
path: root/libavformat/subtitles.c
blob: fce2bf190bfbd09d83b400b728bffe6bf1a669a0 (plain)
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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
/*
 * Copyright (c) 2012-2013 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 "subtitles.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"

AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
                                    const uint8_t *event, int len, int merge)
{
    AVPacket *subs, *sub;

    if (merge && q->nb_subs > 0) {
        /* merge with previous event */

        int old_len;
        sub = &q->subs[q->nb_subs - 1];
        old_len = sub->size;
        if (av_grow_packet(sub, len) < 0)
            return NULL;
        memcpy(sub->data + old_len, event, len);
    } else {
        /* new event */

        if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
            return NULL;
        subs = av_fast_realloc(q->subs, &q->allocated_size,
                               (q->nb_subs + 1) * sizeof(*q->subs));
        if (!subs)
            return NULL;
        q->subs = subs;
        sub = &subs[q->nb_subs++];
        if (av_new_packet(sub, len) < 0)
            return NULL;
        sub->flags |= AV_PKT_FLAG_KEY;
        sub->pts = sub->dts = 0;
        memcpy(sub->data, event, len);
    }
    return sub;
}

static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
{
    const AVPacket *s1 = a;
    const AVPacket *s2 = b;
    if (s1->pts == s2->pts) {
        if (s1->pos == s2->pos)
            return 0;
        return s1->pos > s2->pos ? 1 : -1;
    }
    return s1->pts > s2->pts ? 1 : -1;
}

static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
{
    const AVPacket *s1 = a;
    const AVPacket *s2 = b;
    if (s1->pos == s2->pos) {
        if (s1->pts == s2->pts)
            return 0;
        return s1->pts > s2->pts ? 1 : -1;
    }
    return s1->pos > s2->pos ? 1 : -1;
}

void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
{
    int i;

    qsort(q->subs, q->nb_subs, sizeof(*q->subs),
          q->sort == SUB_SORT_TS_POS ? cmp_pkt_sub_ts_pos
                                     : cmp_pkt_sub_pos_ts);
    for (i = 0; i < q->nb_subs; i++)
        if (q->subs[i].duration == -1 && i < q->nb_subs - 1)
            q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
}

int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
{
    AVPacket *sub = q->subs + q->current_sub_idx;

    if (q->current_sub_idx == q->nb_subs)
        return AVERROR_EOF;
    if (av_copy_packet(pkt, sub) < 0) {
        return AVERROR(ENOMEM);
    }

    pkt->dts = pkt->pts;
    q->current_sub_idx++;
    return 0;
}

static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)
{
    int s1 = 0, s2 = q->nb_subs - 1;

    if (s2 < s1)
        return AVERROR(ERANGE);

    for (;;) {
        int mid;

        if (s1 == s2)
            return s1;
        if (s1 == s2 - 1)
            return q->subs[s1].pts <= q->subs[s2].pts ? s1 : s2;
        mid = (s1 + s2) / 2;
        if (q->subs[mid].pts <= ts)
            s1 = mid;
        else
            s2 = mid;
    }
}

int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
                            int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
    if (flags & AVSEEK_FLAG_BYTE) {
        return AVERROR(ENOSYS);
    } else if (flags & AVSEEK_FLAG_FRAME) {
        if (ts < 0 || ts >= q->nb_subs)
            return AVERROR(ERANGE);
        q->current_sub_idx = ts;
    } else {
        int i, idx = search_sub_ts(q, ts);
        int64_t ts_selected;

        if (idx < 0)
            return idx;
        for (i = idx; i < q->nb_subs && q->subs[i].pts < min_ts; i++)
            if (stream_index == -1 || q->subs[i].stream_index == stream_index)
                idx = i;
        for (i = idx; i > 0 && q->subs[i].pts > max_ts; i--)
            if (stream_index == -1 || q->subs[i].stream_index == stream_index)
                idx = i;

        ts_selected = q->subs[idx].pts;
        if (ts_selected < min_ts || ts_selected > max_ts)
            return AVERROR(ERANGE);

        /* look back in the latest subtitles for overlapping subtitles */
        for (i = idx - 1; i >= 0; i--) {
            int64_t pts = q->subs[i].pts;
            if (q->subs[i].duration <= 0 ||
                (stream_index != -1 && q->subs[i].stream_index != stream_index))
                continue;
            if (pts >= min_ts && pts > ts_selected - q->subs[i].duration)
                idx = i;
            else
                break;
        }

        /* If the queue is used to store multiple subtitles streams (like with
         * VobSub) and the stream index is not specified, we need to make sure
         * to focus on the smallest file position offset for a same timestamp;
         * queue is ordered by pts and then filepos, so we can take the first
         * entry for a given timestamp. */
        if (stream_index == -1)
            while (idx > 0 && q->subs[idx - 1].pts == q->subs[idx].pts)
                idx--;

        q->current_sub_idx = idx;
    }
    return 0;
}

void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
{
    int i;

    for (i = 0; i < q->nb_subs; i++)
        av_free_packet(&q->subs[i]);
    av_freep(&q->subs);
    q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
}

int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c)
{
    int i = 0;
    char end_chr;

    if (!*c) // cached char?
        *c = avio_r8(pb);
    if (!*c)
        return 0;

    end_chr = *c == '<' ? '>' : '<';
    do {
        av_bprint_chars(buf, *c, 1);
        *c = avio_r8(pb);
        i++;
    } while (*c != end_chr && *c);
    if (end_chr == '>') {
        av_bprint_chars(buf, '>', 1);
        *c = 0;
    }
    return i;
}

const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
{
    int in_quotes = 0;
    const int len = strlen(attr);

    while (*s) {
        while (*s) {
            if (!in_quotes && av_isspace(*s))
                break;
            in_quotes ^= *s == '"'; // XXX: support escaping?
            s++;
        }
        while (av_isspace(*s))
            s++;
        if (!av_strncasecmp(s, attr, len) && s[len] == '=')
            return s + len + 1 + (s[len + 1] == '"');
    }
    return NULL;
}

static inline int is_eol(char c)
{
    return c == '\r' || c == '\n';
}

void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
{
    char eol_buf[5], last_was_cr = 0;
    int n = 0, i = 0, nb_eol = 0;

    av_bprint_clear(buf);

    for (;;) {
        char c = avio_r8(pb);

        if (!c)
            break;

        /* ignore all initial line breaks */
        if (n == 0 && is_eol(c))
            continue;

        /* line break buffering: we don't want to add the trailing \r\n */
        if (is_eol(c)) {
            nb_eol += c == '\n' || last_was_cr;
            if (nb_eol == 2)
                break;
            eol_buf[i++] = c;
            if (i == sizeof(eol_buf) - 1)
                break;
            last_was_cr = c == '\r';
            continue;
        }

        /* only one line break followed by data: we flush the line breaks
         * buffer */
        if (i) {
            eol_buf[i] = 0;
            av_bprintf(buf, "%s", eol_buf);
            i = nb_eol = 0;
        }

        av_bprint_chars(buf, c, 1);
        n++;
    }
}