1 #include <lib/base/eerror.h>
2 #include <lib/dvb/teletext.h>
3 #include <lib/dvb/idemux.h>
4 #include <lib/gdi/gpixmap.h>
7 This is a very simple en300 706 telext decoder.
9 It can only decode a single page at a time, thus it's only used
14 DEFINE_REF(eDVBTeletextParser);
16 /* we asumme error free transmission! */
17 static inline unsigned char decode_odd_parity(unsigned char *b)
20 unsigned char res = 0;
27 static inline unsigned char decode_hamming_84(unsigned char *b)
29 unsigned char res = 0;
37 static inline unsigned long decode_hamming_2418(unsigned char *b)
39 unsigned long h24 = b[0] | (b[1] << 8) | (b[2] << 16);
42 ((h24 & 0x000004) >> 2) |
43 ((h24 & 0x000070) >> 3) |
44 ((h24 & 0x007f00) >> 4) |
45 ((h24 & 0x7f0000) >> 5);
48 eDVBTeletextParser::eDVBTeletextParser(iDVBDemux *demux)
50 setStreamID(0xBD); /* as per en 300 472 */
54 if (demux->createPESReader(eApp, m_pes_reader))
55 eDebug("failed to create PES reader!");
57 m_pes_reader->connectRead(slot(*this, &eDVBTeletextParser::processData), m_read_connection);
60 eDVBTeletextParser::~eDVBTeletextParser()
64 void eDVBTeletextParser::processPESPacket(__u8 *pkt, int len)
66 unsigned char *p = pkt;
68 p += 4; len -= 4; /* start code, already be verified by pes parser */
69 p += 2; len -= 2; /* length, better use the argument */
71 p += 3; len -= 3; /* pes header */
73 p += 0x24; len -= 0x24; /* skip header */
75 // eDebug("data identifier: %02x", *p);
81 unsigned char data_unit_id = *p++;
82 unsigned char data_unit_length = *p++;
85 if (len < data_unit_length)
87 eDebug("data_unit_length > len");
91 if (data_unit_length != 44)
93 eDebug("illegal data unit length %d", data_unit_length);
97 unsigned char line_offset = *p++; len--;
98 unsigned char framing_code = *p++; len--;
100 int magazine_and_packet_address = decode_hamming_84(p++); len--;
101 magazine_and_packet_address |= decode_hamming_84(p++)<<4; len--;
103 unsigned char *data = p; p += 40; len -= 40;
105 if (framing_code != 0xe4) /* no teletxt data */
108 m_M = magazine_and_packet_address & 7;
109 m_Y = magazine_and_packet_address >> 3;
110 // eDebug("line %d, framing code: %02x, M=%02x, Y=%02x", line_offset, framing_code, M, Y);
112 if (m_Y == 0) /* page header */
116 m_S1 = decode_hamming_84(data + 2); /* S1 */
117 int S2C4 = decode_hamming_84(data + 3);
120 m_C |= (S2C4 & 8) ? (1<<4) : 0;
122 m_S3 = decode_hamming_84(data + 4);
124 int S4C5C6 = decode_hamming_84(data + 5);
127 m_C |= (S4C5C6 & 0xC) << 3;
129 m_C |= decode_hamming_84(data + 6) << 7;
130 m_C |= decode_hamming_84(data + 7) << 11;
132 /* page on the same magazine? end current page. */
133 if ((m_M == m_page_M) && (m_page_open))
139 m_X = decode_hamming_84(data+1) * 0x10 + decode_hamming_84(data);
141 /* correct page on correct magazine? open page. */
142 if ((m_M == m_page_M) && (m_X == m_page_X))
146 handleLine(data + 8, 32);
150 /* data for the selected page? */
151 if ((m_M == m_page_M) && m_page_open)
152 handleLine(data, 40);
157 int eDVBTeletextParser::start(int pid)
162 return m_pes_reader->start(pid);
167 void eDVBTeletextParser::handlePageStart()
169 if (m_C & (1<<4)) /* erase flag set */
170 m_subtitle_page.clear();
173 void eDVBTeletextParser::handleLine(unsigned char *data, int len)
175 if (!m_Y) /* first line is page header, we don't need that. */
178 int last_was_white = 1, color = -1;
182 for (int i=0; i<len; ++i)
184 unsigned char b = decode_odd_parity(data + i);
186 if (b < 0x10) /* spacing attribute */
188 if (b < 8) /* colors */
190 if (b != color) /* new color is split into a new string */
193 addSubtitleString(color, text);
198 /* ignore other attributes */
201 /* no more than one whitespace, only printable chars */
202 if (((!last_was_white) || (b != ' ')) && (b >= 0x20))
205 last_was_white = b == ' ';
209 addSubtitleString(color, text);
212 void eDVBTeletextParser::handlePageEnd()
214 addSubtitleString(-1, ""); /* end last line */
215 sendSubtitlePage(); /* send assembled subtitle page to display */
218 void eDVBTeletextParser::setPage(int page)
220 m_page_M = (page >> 8) & 7; /* magazine to look for */
221 m_page_X = page & 0xFF; /* page number */
224 void eDVBTeletextParser::addSubtitleString(int color, const std::string &string)
226 if ((color != m_subtitle_color) && !m_subtitle_text.empty())
228 m_subtitle_page.m_elements.push_back(eDVBTeletextSubtitlePageElement(gRGB(0, 0xff, 0), m_subtitle_text));
229 m_subtitle_text = "";
230 } else if (!m_subtitle_text.empty() && m_subtitle_text[m_subtitle_text.size()-1] != ' ')
231 m_subtitle_text += " ";
233 m_subtitle_color = color;
234 m_subtitle_text += string;
237 void eDVBTeletextParser::sendSubtitlePage()
239 eDebug("subtitle page:");
240 for (unsigned int i = 0; i < m_subtitle_page.m_elements.size(); ++i)
241 eDebug("%s", m_subtitle_page.m_elements[i].m_text.c_str());