summaryrefslogtreecommitdiffstats
path: root/libavcodec/srtdec.c
blob: ed3af95063b4f7fa46b448efe5321ddf89821215 (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
/*
 * SubRip subtitle decoder
 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
 *
 * 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 "libavutil/avstring.h"
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/parseutils.h"
#include "avcodec.h"
#include "ass.h"

static int html_color_parse(AVCodecContext *avctx, const char *str)
{
    uint8_t rgba[4];
    if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
        return -1;
    return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
}

enum {
    PARAM_UNKNOWN = -1,
    PARAM_SIZE,
    PARAM_COLOR,
    PARAM_FACE,
    PARAM_NUMBER
};

typedef struct SrtStack {
    char tag[128];
    char param[PARAM_NUMBER][128];
} SrtStack;

static void rstrip_spaces_buf(AVBPrint *buf)
{
    while (buf->len > 0 && buf->str[buf->len - 1] == ' ')
        buf->str[--buf->len] = 0;
}

static void srt_to_ass(AVCodecContext *avctx, AVBPrint *dst,
                       const char *in, int x1, int y1, int x2, int y2)
{
    char *param, buffer[128], tmp[128];
    int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
    SrtStack stack[16];

    stack[0].tag[0] = 0;
    strcpy(stack[0].param[PARAM_SIZE],  "{\\fs}");
    strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
    strcpy(stack[0].param[PARAM_FACE],  "{\\fn}");

    if (x1 >= 0 && y1 >= 0) {
        /* XXX: here we rescale coordinate assuming they are in DVD resolution
         * (720x480) since we don't have anything better */

        if (x2 >= 0 && y2 >= 0 && (x2 != x1 || y2 != y1) && x2 >= x1 && y2 >= y1) {
            /* text rectangle defined, write the text at the center of the rectangle */
            const int cx = x1 + (x2 - x1)/2;
            const int cy = y1 + (y2 - y1)/2;
            const int scaled_x = cx * ASS_DEFAULT_PLAYRESX / 720;
            const int scaled_y = cy * ASS_DEFAULT_PLAYRESY / 480;
            av_bprintf(dst, "{\\an5}{\\pos(%d,%d)}", scaled_x, scaled_y);
        } else {
            /* only the top left corner, assume the text starts in that corner */
            const int scaled_x = x1 * ASS_DEFAULT_PLAYRESX / 720;
            const int scaled_y = y1 * ASS_DEFAULT_PLAYRESY / 480;
            av_bprintf(dst, "{\\an1}{\\pos(%d,%d)}", scaled_x, scaled_y);
        }
    }

    for (; !end && *in; in++) {
        switch (*in) {
        case '\r':
            break;
        case '\n':
            if (line_start) {
                end = 1;
                break;
            }
            rstrip_spaces_buf(dst);
            av_bprintf(dst, "\\N");
            line_start = 1;
            break;
        case ' ':
            if (!line_start)
                av_bprint_chars(dst, *in, 1);
            break;
        case '{':    /* skip all {\xxx} substrings except for {\an%d}
                        and all microdvd like styles such as {Y:xxx} */
            len = 0;
            an += sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0;
            if ((an != 1 && (len = 0, sscanf(in, "{\\%*[^}]}%n", &len) >= 0 && len > 0)) ||
                (len = 0, sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n", &len) >= 0 && len > 0)) {
                in += len - 1;
            } else
                av_bprint_chars(dst, *in, 1);
            break;
        case '<':
            tag_close = in[1] == '/';
            len = 0;
            if (sscanf(in+tag_close+1, "%127[^>]>%n", buffer, &len) >= 1 && len > 0) {
                if ((param = strchr(buffer, ' ')))
                    *param++ = 0;
                if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
                    ( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
                    int i, j, unknown = 0;
                    in += len + tag_close;
                    if (!tag_close)
                        memset(stack+sptr, 0, sizeof(*stack));
                    if (!strcmp(buffer, "font")) {
                        if (tag_close) {
                            for (i=PARAM_NUMBER-1; i>=0; i--)
                                if (stack[sptr-1].param[i][0])
                                    for (j=sptr-2; j>=0; j--)
                                        if (stack[j].param[i][0]) {
                                            av_bprintf(dst, "%s", stack[j].param[i]);
                                            break;
                                        }
                        } else {
                            while (param) {
                                if (!strncmp(param, "size=", 5)) {
                                    unsigned font_size;
                                    param += 5 + (param[5] == '"');
                                    if (sscanf(param, "%u", &font_size) == 1) {
                                        snprintf(stack[sptr].param[PARAM_SIZE],
                                             sizeof(stack[0].param[PARAM_SIZE]),
                                             "{\\fs%u}", font_size);
                                    }
                                } else if (!strncmp(param, "color=", 6)) {
                                    param += 6 + (param[6] == '"');
                                    snprintf(stack[sptr].param[PARAM_COLOR],
                                         sizeof(stack[0].param[PARAM_COLOR]),
                                         "{\\c&H%X&}",
                                         html_color_parse(avctx, param));
                                } else if (!strncmp(param, "face=", 5)) {
                                    param += 5 + (param[5] == '"');
                                    len = strcspn(param,
                                                  param[-1] == '"' ? "\"" :" ");
                                    av_strlcpy(tmp, param,
                                               FFMIN(sizeof(tmp), len+1));
                                    param += len;
                                    snprintf(stack[sptr].param[PARAM_FACE],
                                             sizeof(stack[0].param[PARAM_FACE]),
                                             "{\\fn%s}", tmp);
                                }
                                if ((param = strchr(param, ' ')))
                                    param++;
                            }
                            for (i=0; i<PARAM_NUMBER; i++)
                                if (stack[sptr].param[i][0])
                                    av_bprintf(dst, "%s", stack[sptr].param[i]);
                        }
                    } else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
                        av_bprintf(dst, "{\\%c%d}", buffer[0], !tag_close);
                    } else {
                        unknown = 1;
                        snprintf(tmp, sizeof(tmp), "</%s>", buffer);
                    }
                    if (tag_close) {
                        sptr--;
                    } else if (unknown && !strstr(in, tmp)) {
                        in -= len + tag_close;
                        av_bprint_chars(dst, *in, 1);
                    } else
                        av_strlcpy(stack[sptr++].tag, buffer,
                                   sizeof(stack[0].tag));
                    break;
                }
            }
        default:
            av_bprint_chars(dst, *in, 1);
            break;
        }
        if (*in != ' ' && *in != '\r' && *in != '\n')
            line_start = 0;
    }

    while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2))
        dst->len -= 2;
    dst->str[dst->len] = 0;
    rstrip_spaces_buf(dst);
}

static int srt_decode_frame(AVCodecContext *avctx,
                            void *data, int *got_sub_ptr, AVPacket *avpkt)
{
    AVSubtitle *sub = data;
    AVBPrint buffer;
    int ts_start, ts_end, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
    int size, ret;
    const uint8_t *p = av_packet_get_side_data(avpkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);

    if (p && size == 16) {
        x1 = AV_RL32(p     );
        y1 = AV_RL32(p +  4);
        x2 = AV_RL32(p +  8);
        y2 = AV_RL32(p + 12);
    }

    if (avpkt->size <= 0)
        return avpkt->size;

    av_bprint_init(&buffer, 0, AV_BPRINT_SIZE_UNLIMITED);

        // TODO: reindent
            // Do final divide-by-10 outside rescale to force rounding down.
            ts_start = av_rescale_q(avpkt->pts,
                                    avctx->time_base,
                                    (AVRational){1,100});
            ts_end   = av_rescale_q(avpkt->pts + avpkt->duration,
                                    avctx->time_base,
                                    (AVRational){1,100});

    srt_to_ass(avctx, &buffer, avpkt->data, x1, y1, x2, y2);
    ret = ff_ass_add_rect_bprint(sub, &buffer, ts_start, ts_end-ts_start);
    av_bprint_finalize(&buffer, NULL);
    if (ret < 0)
        return ret;

    *got_sub_ptr = sub->num_rects > 0;
    return avpkt->size;
}

#if CONFIG_SRT_DECODER
/* deprecated decoder */
AVCodec ff_srt_decoder = {
    .name         = "srt",
    .long_name    = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
    .type         = AVMEDIA_TYPE_SUBTITLE,
    .id           = AV_CODEC_ID_SUBRIP,
    .init         = ff_ass_subtitle_header_default,
    .decode       = srt_decode_frame,
};
#endif

#if CONFIG_SUBRIP_DECODER
AVCodec ff_subrip_decoder = {
    .name         = "subrip",
    .long_name    = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
    .type         = AVMEDIA_TYPE_SUBTITLE,
    .id           = AV_CODEC_ID_SUBRIP,
    .init         = ff_ass_subtitle_header_default,
    .decode       = srt_decode_frame,
};
#endif
OpenPOWER on IntegriCloud