MythTV  master
teletextdecoder.cpp
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1 /* =============================================================
2  * File : vbidecoder.cpp
3  * Author: Frank Muenchow <beebof@gmx.de>
4  * Martin Barnasconi
5  * Date : 2005-10-25
6  *
7  * This program is free software; you can redistribute it
8  * and/or modify it under the terms of the GNU General
9  * Public License as published by the Free Software Foundation;
10  * either version 2, or (at your option)
11  * any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * ============================================================= */
19 #include <cctype>
20 #include <cstdint>
21 #include <cstring>
22 
23 extern "C" {
24 #include <cinttypes>
25 }
26 
29 #include "osd.h"
30 #include "vbilut.h"
31 
38 void TeletextDecoder::Decode(const unsigned char *buf, int vbimode)
39 {
40  int err = 0;
41  int latin1 = -1;
42  int pagenum = 0;
43  int subpagenum = 0;
44  int lang = 0;
45  int flags = 0;
46  uint magazine = 0;
47  uint packet = 0;
48  uint header = 0;
49 
50  if (!m_teletextReader)
51  return;
52 
54 
55  switch (vbimode)
56  {
57  case VBI_IVTV:
58  header = hamm16(buf, &err);
59 
60  if (err & 0xf000)
61  return; // error in data header
62 
63  magazine = header & 7;
64  packet = (header >> 3) & 0x1f;
65 
66  buf += 2;
67  break;
68 
69  case VBI_DVB:
70  case VBI_DVB_SUBTITLE:
71  // zahl1 = hamm84(buf,&err) * 16 + hamm84(buf+1,&err);
72 
73  magazine = 0;
74  if (buf[0] & 0x40)
75  magazine += 1;
76  if (buf[0] & 0x10)
77  magazine += 2;
78  if (buf[0] & 0x04)
79  magazine += 4;
80 
81  packet = 0;
82  if (buf[0] & 0x01)
83  packet += 1;
84  if (buf[1] & 0x40)
85  packet += 2;
86  if (buf[1] & 0x10)
87  packet += 4;
88  if (buf[1] & 0x04)
89  packet += 8;
90  if (buf[1] & 0x01)
91  packet += 16;
92 
93  if (err == 1)
94  return; // error in data header
95 
96  buf += 2;
97  break;
98 
99  default:
100  return; // error in vbimode
101  }
102 
103  int b1=0;
104  int b2=0;
105  int b3=0;
106  int b4=0;
107  switch (packet)
108  {
109  case 0: // Page Header
110  switch (vbimode)
111  {
112  case VBI_IVTV:
113  b1 = hamm16(buf, &err);// page number
114  b2 = hamm16(buf+2, &err);// subpage number + flags
115  b3 = hamm16(buf+4, &err);// subpage number + flags
116  b4 = hamm16(buf+6, &err);// language code + more flags
117  if (err & 0xf000)
118  return;
119 
120  break;
121 
122  case VBI_DVB:
123  case VBI_DVB_SUBTITLE:
124  b1 = hamm84(buf+1, &err)*16+hamm84(buf, &err);
125  b2 = hamm84(buf+3, &err)*16+hamm84(buf+2, &err);
126  b3 = hamm84(buf+5, &err)*16+hamm84(buf+4, &err);
127  b4 = hamm84(buf+7, &err)*16+hamm84(buf+6, &err);
128  if (err == 1)
129  return;
130 
131  break;
132 
133  default:
134  return; // error in vbimode
135  }
136 
137  subpagenum= (b2 + b3 * 256) & 0x3f7f;
138  pagenum = (magazine ? magazine : 8)*256 + b1;
139 
140  lang = "\0\4\2\6\1\5\3\7"[b4 >> 5] + (latin1 ? 0 : 8);
141  flags = b4 & 0x1F;
142  flags |= b3 & 0xC0;
143  flags |= (b2 & 0x80) >> 2;
144  m_teletextReader->AddPageHeader(pagenum, subpagenum, buf,
145  vbimode, lang, flags);
146 
147  break;
148 
149  default: // Page Data
150  m_teletextReader->AddTeletextData((magazine ? magazine : 8), packet,
151  buf, vbimode);
152  break;
153  }
154 }
hamm84
int hamm84(const uint8_t *p, int *err)
Definition: vbilut.cpp:333
TeletextDecoder::Decode
void Decode(const unsigned char *buf, int vbimode)
Decodes teletext data.
Definition: teletextdecoder.cpp:38
VBI_IVTV
@ VBI_IVTV
Definition: vbilut.h:23
osd.h
teletextreader.h
vbilut.h
VBI_DVB_SUBTITLE
@ VBI_DVB_SUBTITLE
< DVB packet
Definition: vbilut.h:25
VBI_DVB
@ VBI_DVB
< IVTV packet
Definition: vbilut.h:24
TeletextDecoder::m_teletextReader
TeletextReader * m_teletextReader
Definition: teletextdecoder.h:19
vbimode
vbimode
Definition: vbilut.h:21
TeletextReader::AddTeletextData
void AddTeletextData(int magazine, int row, const uint8_t *buf, int vbimode)
Definition: teletextreader.cpp:403
TeletextReader::AddPageHeader
void AddPageHeader(int page, int subpage, const uint8_t *buf, int vbimode, int lang, int flags)
Definition: teletextreader.cpp:305
hamm16
int hamm16(const uint8_t *p, int *err)
Definition: vbilut.cpp:343
uint
unsigned int uint
Definition: freesurround.h:24
TeletextDecoder::m_decoderType
int m_decoderType
Definition: teletextdecoder.h:20
teletextdecoder.h