Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / xsubdec.c
CommitLineData
2ba45a60
DM
1/*
2 * XSUB subtitle decoder
3 * Copyright (c) 2007 Reimar Döffinger
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/mathematics.h"
23#include "libavutil/imgutils.h"
24#include "avcodec.h"
25#include "get_bits.h"
26#include "bytestream.h"
27
28static av_cold int decode_init(AVCodecContext *avctx) {
29 avctx->pix_fmt = AV_PIX_FMT_PAL8;
30 return 0;
31}
32
33static const uint8_t tc_offsets[9] = { 0, 1, 3, 4, 6, 7, 9, 10, 11 };
34static const uint8_t tc_muls[9] = { 10, 6, 10, 6, 10, 10, 10, 10, 1 };
35
36static int64_t parse_timecode(const uint8_t *buf, int64_t packet_time) {
37 int i;
38 int64_t ms = 0;
39 if (buf[2] != ':' || buf[5] != ':' || buf[8] != '.')
40 return AV_NOPTS_VALUE;
41 for (i = 0; i < sizeof(tc_offsets); i++) {
42 uint8_t c = buf[tc_offsets[i]] - '0';
43 if (c > 9) return AV_NOPTS_VALUE;
44 ms = (ms + c) * tc_muls[i];
45 }
46 return ms - packet_time;
47}
48
49static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
50 AVPacket *avpkt) {
51 const uint8_t *buf = avpkt->data;
52 int buf_size = avpkt->size;
53 AVSubtitle *sub = data;
54 const uint8_t *buf_end = buf + buf_size;
55 uint8_t *bitmap;
56 int w, h, x, y, i;
57 int64_t packet_time = 0;
58 GetBitContext gb;
59 int has_alpha = avctx->codec_tag == MKTAG('D','X','S','A');
60
61 // check that at least header fits
62 if (buf_size < 27 + 7 * 2 + 4 * 3) {
63 av_log(avctx, AV_LOG_ERROR, "coded frame size %d too small\n", buf_size);
64 return -1;
65 }
66
67 // read start and end time
68 if (buf[0] != '[' || buf[13] != '-' || buf[26] != ']') {
69 av_log(avctx, AV_LOG_ERROR, "invalid time code\n");
70 return -1;
71 }
72 if (avpkt->pts != AV_NOPTS_VALUE)
73 packet_time = av_rescale_q(avpkt->pts, AV_TIME_BASE_Q, (AVRational){1, 1000});
74 sub->start_display_time = parse_timecode(buf + 1, packet_time);
75 sub->end_display_time = parse_timecode(buf + 14, packet_time);
76 buf += 27;
77
78 // read header
79 w = bytestream_get_le16(&buf);
80 h = bytestream_get_le16(&buf);
81 if (av_image_check_size(w, h, 0, avctx) < 0)
82 return -1;
83 x = bytestream_get_le16(&buf);
84 y = bytestream_get_le16(&buf);
85 // skip bottom right position, it gives no new information
86 bytestream_get_le16(&buf);
87 bytestream_get_le16(&buf);
88 // The following value is supposed to indicate the start offset
89 // (relative to the palette) of the data for the second field,
90 // however there are files in which it has a bogus value and thus
91 // we just ignore it
92 bytestream_get_le16(&buf);
93
94 // allocate sub and set values
95 sub->rects = av_mallocz(sizeof(*sub->rects));
96 sub->rects[0] = av_mallocz(sizeof(*sub->rects[0]));
97 sub->num_rects = 1;
98 sub->rects[0]->x = x; sub->rects[0]->y = y;
99 sub->rects[0]->w = w; sub->rects[0]->h = h;
100 sub->rects[0]->type = SUBTITLE_BITMAP;
101 sub->rects[0]->pict.linesize[0] = w;
102 sub->rects[0]->pict.data[0] = av_malloc(w * h);
103 sub->rects[0]->nb_colors = 4;
104 sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
105
106 // read palette
107 for (i = 0; i < sub->rects[0]->nb_colors; i++)
108 ((uint32_t*)sub->rects[0]->pict.data[1])[i] = bytestream_get_be24(&buf);
109 // make all except background (first entry) non-transparent
110 for (i = 0; i < sub->rects[0]->nb_colors; i++)
111 ((uint32_t*)sub->rects[0]->pict.data[1])[i] |= (has_alpha ? *buf++ : (i ? 0xff : 0)) << 24;
112
113 // process RLE-compressed data
114 init_get_bits(&gb, buf, (buf_end - buf) * 8);
115 bitmap = sub->rects[0]->pict.data[0];
116 for (y = 0; y < h; y++) {
117 // interlaced: do odd lines
118 if (y == (h + 1) / 2) bitmap = sub->rects[0]->pict.data[0] + w;
119 for (x = 0; x < w; ) {
120 int log2 = ff_log2_tab[show_bits(&gb, 8)];
121 int run = get_bits(&gb, 14 - 4 * (log2 >> 1));
122 int color = get_bits(&gb, 2);
123 run = FFMIN(run, w - x);
124 // run length 0 means till end of row
125 if (!run) run = w - x;
126 memset(bitmap, color, run);
127 bitmap += run;
128 x += run;
129 }
130 // interlaced, skip every second line
131 bitmap += w;
132 align_get_bits(&gb);
133 }
134 *data_size = 1;
135 return buf_size;
136}
137
138AVCodec ff_xsub_decoder = {
139 .name = "xsub",
140 .long_name = NULL_IF_CONFIG_SMALL("XSUB"),
141 .type = AVMEDIA_TYPE_SUBTITLE,
142 .id = AV_CODEC_ID_XSUB,
143 .init = decode_init,
144 .decode = decode_frame,
145};