modules/codec/stl.c

   1 /*****************************************************************************
   2  * stl.c: EBU STL decoder
   3  *****************************************************************************
   4  * Copyright (C) 2010 Laurent Aimar
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30 #include <assert.h>
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_codec.h>
  35 #include <vlc_memory.h>
  36 #include <vlc_charset.h>
  37
  38 /*****************************************************************************
  39  * Module descriptor
  40  *****************************************************************************/
  41 static int  Open (vlc_object_t *);
  42 static void Close(vlc_object_t *);
  43
  44 vlc_module_begin()
  45     set_description(N_("EBU STL subtitles decoder"))
  46     set_category(CAT_INPUT)
  47     set_subcategory(SUBCAT_INPUT_SCODEC)
  48     set_capability("decoder", 10)
  49     set_callbacks(Open, Close)
  50 vlc_module_end()
  51
  52 /*****************************************************************************
  53  * Local definitions/prototypes
  54  *****************************************************************************/
  55 #define GSI_BLOCK_SIZE 1024
  56
  57 typedef enum {
  58     CCT_ISO_6937_2 = 0x3030, CCT_BEGIN = CCT_ISO_6937_2,
  59     CCT_ISO_8859_5 = 0x3031,
  60     CCT_ISO_8859_6 = 0x3032,
  61     CCT_ISO_8859_7 = 0x3033,
  62     CCT_ISO_8859_8 = 0x3034, CCT_END = CCT_ISO_8859_8
  63 } cct_number_value_t;
  64
  65 typedef struct {
  66     cct_number_value_t value;
  67     const char *str;
  68 } cct_number_t;
  69
  70 struct decoder_sys_t {
  71     cct_number_value_t cct;
  72 };
  73
  74 static cct_number_t cct_nums[] = { {CCT_ISO_6937_2, "ISO_6937-2"},
  75                                    {CCT_ISO_8859_5, "ISO_8859-5"},
  76                                    {CCT_ISO_8859_6, "ISO_8859-6"},
  77                                    {CCT_ISO_8859_7, "ISO_8859-7"},
  78                                    {CCT_ISO_8859_8, "ISO_8859-8"} };
  79
  80
  81 static char *ParseText(const uint8_t *data, size_t size, const char *charset)
  82 {
  83     char *text = malloc(size);
  84     if (text == NULL)
  85         return NULL;
  86
  87     size_t text_size = 0;
  88
  89     for (size_t i = 0; i < size; i++) {
  90         uint8_t code = data[i];
  91
  92         if (code == 0x8f)
  93             break;
  94         if (code == 0x7f)
  95             continue;
  96         /* TODO: italics begin/end 0x80/0x81, underline being/end 0x82/0x83 */
  97         if (code & 0x60)
  98             text[text_size++] = code;
  99         if (code == 0x8a)
 100             text[text_size++] = '\n';
 101     }
 102
 103     char *u8 = FromCharset(charset, text, text_size);
 104     free(text);
 105     return u8;
 106 }
 107
 108 static subpicture_t *Decode(decoder_t *dec, block_t **block)
 109 {
 110     if (block == NULL || *block == NULL)
 111         return NULL;
 112
 113     subpicture_t *sub = NULL;
 114
 115     block_t *b = *block; *block = NULL;
 116     if (b->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED))
 117         goto exit;
 118     if (b->i_buffer < 128)
 119         goto exit;
 120
 121     int     payload_size = (b->i_buffer / 128) * 112;
 122     uint8_t *payload = malloc(payload_size);
 123     if (!payload)
 124         goto exit;
 125     for (unsigned i = 0; i < b->i_buffer / 128; i++)
 126         memcpy(&payload[112 * i], &b->p_buffer[128 * i + 16], 112);
 127
 128     sub = decoder_NewSubpicture(dec, NULL);
 129     if (!sub) {
 130         free(payload);
 131         goto exit;
 132     }
 133     sub->i_start    = b->i_pts;
 134     sub->i_stop     = b->i_pts + b->i_length;
 135     sub->b_ephemer  = b->i_length == 0;
 136     sub->b_absolute = false;
 137     //sub->i_original_picture_width  = 0;
 138     //sub->i_original_picture_height = 0;
 139
 140     video_format_t fmt;
 141     video_format_Init(&fmt, VLC_CODEC_TEXT);
 142     sub->p_region = subpicture_region_New(&fmt);
 143     video_format_Clean(&fmt);
 144
 145     if (sub->p_region) {
 146         sub->p_region->p_text = text_segment_New( ParseText(payload,
 147                                             payload_size,
 148                                             cct_nums[dec->p_sys->cct - CCT_BEGIN].str) );
 149         sub->p_region->i_align = SUBPICTURE_ALIGN_BOTTOM;
 150     }
 151
 152     free(payload);
 153
 154 exit:
 155     block_Release(b);
 156     return sub;
 157 }
 158
 159 static int ExtractCCT(const decoder_t *dec, cct_number_value_t *cct_number)
 160 {
 161     uint8_t *header = dec->fmt_in.p_extra;
 162     if (!header) {
 163         msg_Err(dec, "NULL EBU header (GSI block)\n");
 164         return VLC_EGENERIC;
 165     }
 166
 167     if (GSI_BLOCK_SIZE != dec->fmt_in.i_extra) {
 168         msg_Err(dec, "EBU header is not in expected size (%d)\n", dec->fmt_in.i_extra);
 169         return VLC_EGENERIC;
 170     }
 171
 172     int cct = (header[12] << 8) | header[13];
 173     if (CCT_BEGIN > cct || CCT_END < cct) {
 174         msg_Err(dec, "EBU header contains illegal CCT (0x%x)\n", cct);
 175         return VLC_EGENERIC;
 176     }
 177
 178     *cct_number = cct;
 179
 180     return VLC_SUCCESS;
 181 }
 182
 183 static int Open(vlc_object_t *object)
 184 {
 185     decoder_t *dec = (decoder_t*)object;
 186
 187     if (dec->fmt_in.i_codec != VLC_CODEC_EBU_STL)
 188         return VLC_EGENERIC;
 189
 190     cct_number_value_t cct;
 191     int rc = ExtractCCT(dec, &cct);
 192     if (VLC_SUCCESS != rc)
 193         return rc;
 194
 195     msg_Dbg(dec, "CCT=0x%x", cct);
 196
 197     decoder_sys_t *sys = malloc(sizeof(*sys));
 198     if (!sys)
 199         return VLC_ENOMEM;
 200
 201     sys->cct = cct;
 202
 203     dec->p_sys = sys;
 204     dec->pf_decode_sub = Decode;
 205     dec->fmt_out.i_cat = SPU_ES;
 206     dec->fmt_out.i_codec = 0;
 207     return VLC_SUCCESS;
 208 }
 209
 210 static void Close(vlc_object_t *object)
 211 {
 212     decoder_t *dec = (decoder_t*)object;
 213     decoder_sys_t *sys = dec->p_sys;
 214
 215     free(sys);
 216 }