1/* 2 * XSUB subtitle decoder 3 * Copyright (c) 2007 Reimar D��ffinger 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#include "avcodec.h" 22#include "get_bits.h" 23#include "bytestream.h" 24 25static av_cold int decode_init(AVCodecContext *avctx) { 26 avctx->pix_fmt = PIX_FMT_PAL8; 27 return 0; 28} 29 30static const uint8_t tc_offsets[9] = { 0, 1, 3, 4, 6, 7, 9, 10, 11 }; 31static const uint8_t tc_muls[9] = { 10, 6, 10, 6, 10, 10, 10, 10, 1 }; 32 33static int64_t parse_timecode(const uint8_t *buf, int64_t packet_time) { 34 int i; 35 int64_t ms = 0; 36 if (buf[2] != ':' || buf[5] != ':' || buf[8] != '.') 37 return AV_NOPTS_VALUE; 38 for (i = 0; i < sizeof(tc_offsets); i++) { 39 uint8_t c = buf[tc_offsets[i]] - '0'; 40 if (c > 9) return AV_NOPTS_VALUE; 41 ms = (ms + c) * tc_muls[i]; 42 } 43 return ms - packet_time; 44} 45 46static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, 47 AVPacket *avpkt) { 48 const uint8_t *buf = avpkt->data; 49 int buf_size = avpkt->size; 50 AVSubtitle *sub = data; 51 const uint8_t *buf_end = buf + buf_size; 52 uint8_t *bitmap; 53 int w, h, x, y, rlelen, i; 54 int64_t packet_time = 0; 55 GetBitContext gb; 56 57 memset(sub, 0, sizeof(*sub)); 58 59 // check that at least header fits 60 if (buf_size < 27 + 7 * 2 + 4 * 3) { 61 av_log(avctx, AV_LOG_ERROR, "coded frame too small\n"); 62 return -1; 63 } 64 65 // read start and end time 66 if (buf[0] != '[' || buf[13] != '-' || buf[26] != ']') { 67 av_log(avctx, AV_LOG_ERROR, "invalid time code\n"); 68 return -1; 69 } 70 if (avpkt->pts != AV_NOPTS_VALUE) 71 packet_time = av_rescale_q(avpkt->pts, AV_TIME_BASE_Q, (AVRational){1, 1000}); 72 sub->start_display_time = parse_timecode(buf + 1, packet_time); 73 sub->end_display_time = parse_timecode(buf + 14, packet_time); 74 buf += 27; 75 76 // read header 77 w = bytestream_get_le16(&buf); 78 h = bytestream_get_le16(&buf); 79 if (avcodec_check_dimensions(avctx, w, h) < 0) 80 return -1; 81 x = bytestream_get_le16(&buf); 82 y = bytestream_get_le16(&buf); 83 // skip bottom right position, it gives no new information 84 bytestream_get_le16(&buf); 85 bytestream_get_le16(&buf); 86 rlelen = bytestream_get_le16(&buf); 87 88 // allocate sub and set values 89 sub->rects = av_mallocz(sizeof(*sub->rects)); 90 sub->rects[0] = av_mallocz(sizeof(*sub->rects[0])); 91 sub->num_rects = 1; 92 sub->rects[0]->x = x; sub->rects[0]->y = y; 93 sub->rects[0]->w = w; sub->rects[0]->h = h; 94 sub->rects[0]->type = SUBTITLE_BITMAP; 95 sub->rects[0]->pict.linesize[0] = w; 96 sub->rects[0]->pict.data[0] = av_malloc(w * h); 97 sub->rects[0]->nb_colors = 4; 98 sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); 99 100 // read palette 101 for (i = 0; i < sub->rects[0]->nb_colors; i++) 102 ((uint32_t*)sub->rects[0]->pict.data[1])[i] = bytestream_get_be24(&buf); 103 // make all except background (first entry) non-transparent 104 for (i = 1; i < sub->rects[0]->nb_colors; i++) 105 ((uint32_t*)sub->rects[0]->pict.data[1])[i] |= 0xff000000; 106 107 // process RLE-compressed data 108 rlelen = FFMIN(rlelen, buf_end - buf); 109 init_get_bits(&gb, buf, rlelen * 8); 110 bitmap = sub->rects[0]->pict.data[0]; 111 for (y = 0; y < h; y++) { 112 // interlaced: do odd lines 113 if (y == (h + 1) / 2) bitmap = sub->rects[0]->pict.data[0] + w; 114 for (x = 0; x < w; ) { 115 int log2 = ff_log2_tab[show_bits(&gb, 8)]; 116 int run = get_bits(&gb, 14 - 4 * (log2 >> 1)); 117 int color = get_bits(&gb, 2); 118 run = FFMIN(run, w - x); 119 // run length 0 means till end of row 120 if (!run) run = w - x; 121 memset(bitmap, color, run); 122 bitmap += run; 123 x += run; 124 } 125 // interlaced, skip every second line 126 bitmap += w; 127 align_get_bits(&gb); 128 } 129 *data_size = 1; 130 return buf_size; 131} 132 133AVCodec xsub_decoder = { 134 "xsub", 135 AVMEDIA_TYPE_SUBTITLE, 136 CODEC_ID_XSUB, 137 0, 138 decode_init, 139 NULL, 140 NULL, 141 decode_frame, 142 .long_name = NULL_IF_CONFIG_SMALL("XSUB"), 143}; 144