2 Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include "exceptions.h"
23 #include "film_state.h"
26 using namespace boost;
28 Subtitle::Subtitle (AVSubtitle const & sub)
30 /* subtitle PTS in seconds */
31 float const packet_time = (sub.pts / AV_TIME_BASE) + float (sub.pts % AV_TIME_BASE) / 1e6;
33 /* hence start time for this sub */
34 _from = packet_time + (double (sub.start_display_time) / 1e3);
35 _to = packet_time + (double (sub.end_display_time) / 1e3);
37 for (unsigned int i = 0; i < sub.num_rects; ++i) {
38 _images.push_back (shared_ptr<SubtitleImage> (new SubtitleImage (sub.rects[i])));
42 /** @param t Time in seconds from the start of the film */
44 Subtitle::displayed_at (double t)
46 return t >= _from && t <= _to;
49 SubtitleImage::SubtitleImage (AVSubtitleRect const * rect)
50 : _position (rect->x, rect->y)
51 , _image (new SimpleImage (PIX_FMT_RGBA, Size (rect->w, rect->h)))
53 if (rect->type != SUBTITLE_BITMAP) {
54 throw DecodeError ("non-bitmap subtitles not yet supported");
57 /* Start of the first line in the subtitle */
58 uint8_t* sub_p = rect->pict.data[0];
59 /* sub_p looks up into a RGB palette which is here */
60 uint32_t const * palette = (uint32_t *) rect->pict.data[1];
61 /* Start of the output data */
62 uint32_t* out_p = (uint32_t *) _image->data()[0];
64 for (int y = 0; y < rect->h; ++y) {
65 uint8_t* sub_line_p = sub_p;
66 for (int x = 0; x < rect->w; ++x) {
67 *out_p++ = palette[*sub_line_p++];
69 sub_p += rect->pict.linesize[0];
74 transformed_subtitle_area (
75 float target_x_scale, float target_y_scale,
76 Rectangle sub_area, int subtitle_offset, float subtitle_scale
81 sub_area.y += subtitle_offset;
83 /* We will scale the subtitle by the same amount as the video frame, and also by the additional
86 tx.w = sub_area.w * target_x_scale * subtitle_scale;
87 tx.h = sub_area.h * target_y_scale * subtitle_scale;
89 /* Then we need a corrective translation, consisting of two parts:
91 * 1. that which is the result of the scaling of the subtitle by target_x_scale and target_y_scale; this will be
92 * sub_area.x * target_x_scale and sub_area.y * target_y_scale.
94 * 2. that to shift the origin of the scale by subtitle_scale to the centre of the subtitle; this will be
95 * (width_before_subtitle_scale * (1 - subtitle_scale) / 2) and
96 * (height_before_subtitle_scale * (1 - subtitle_scale) / 2).
98 * Combining these two translations gives these expressions.
101 tx.x = target_x_scale * (sub_area.x + (sub_area.w * (1 - subtitle_scale) / 2));
102 tx.y = target_y_scale * (sub_area.y + (sub_area.h * (1 - subtitle_scale) / 2));
108 SubtitleImage::area () const
110 return Rectangle (_position.x, _position.y, _image->size().width, _image->size().height);