From a262e80aef98d57cc90a397629671124f4fa08f2 Mon Sep 17 00:00:00 2001 From: Felix Domke Date: Sun, 21 May 2006 21:24:20 +0000 Subject: [PATCH] some more work on teletext single-page parsing --- lib/dvb/teletext.cpp | 223 +++++++++++++++++++++++++++++++++++++++++-- lib/dvb/teletext.h | 39 ++++++++ 2 files changed, 255 insertions(+), 7 deletions(-) diff --git a/lib/dvb/teletext.cpp b/lib/dvb/teletext.cpp index e05891c4..17020bb3 100644 --- a/lib/dvb/teletext.cpp +++ b/lib/dvb/teletext.cpp @@ -1,33 +1,242 @@ #include #include #include +#include + +/* + This is a very simple en300 706 telext decoder. + + It can only decode a single page at a time, thus it's only used + for subtitles. + + */ DEFINE_REF(eDVBTeletextParser); + /* we asumme error free transmission! */ +static inline unsigned char decode_odd_parity(unsigned char *b) +{ + int i; + unsigned char res = 0; + for (i=0; i<7; ++i) + if (*b & (0x80 >> i)) + res |= 1<> 3) & 2; + res |= (*b >> 6) & 1; + return res; +} + +static inline unsigned long decode_hamming_2418(unsigned char *b) +{ + unsigned long h24 = b[0] | (b[1] << 8) | (b[2] << 16); + + return + ((h24 & 0x000004) >> 2) | + ((h24 & 0x000070) >> 3) | + ((h24 & 0x007f00) >> 4) | + ((h24 & 0x7f0000) >> 5); +} + eDVBTeletextParser::eDVBTeletextParser(iDVBDemux *demux) { - setStreamID(0xBD); // as per en 300 472 + setStreamID(0xBD); /* as per en 300 472 */ + + setPage(0x150); if (demux->createPESReader(eApp, m_pes_reader)) eDebug("failed to create PES reader!"); else m_pes_reader->connectRead(slot(*this, &eDVBTeletextParser::processData), m_read_connection); - +} + +eDVBTeletextParser::~eDVBTeletextParser() +{ } void eDVBTeletextParser::processPESPacket(__u8 *pkt, int len) { - eDebug("GOT TELETEXT PACKET:"); - int i; - for (i=0; i<16; ++i) - eDebugNoNewLine("%02x ", pkt[i]); - eDebug("<"); + unsigned char *p = pkt; + + p += 4; len -= 4; /* start code, already be verified by pes parser */ + p += 2; len -= 2; /* length, better use the argument */ + + p += 3; len -= 3; /* pes header */ + + p += 0x24; len -= 0x24; /* skip header */ + +// eDebug("data identifier: %02x", *p); + + p++; len--; + + while (len > 2) + { + unsigned char data_unit_id = *p++; + unsigned char data_unit_length = *p++; + len -= 2; + + if (len < data_unit_length) + { + eDebug("data_unit_length > len"); + break; + } + + if (data_unit_length != 44) + { + eDebug("illegal data unit length %d", data_unit_length); + break; + } + + unsigned char line_offset = *p++; len--; + unsigned char framing_code = *p++; len--; + + int magazine_and_packet_address = decode_hamming_84(p++); len--; + magazine_and_packet_address |= decode_hamming_84(p++)<<4; len--; + + unsigned char *data = p; p += 40; len -= 40; + + if (framing_code != 0xe4) /* no teletxt data */ + continue; + + m_M = magazine_and_packet_address & 7; + m_Y = magazine_and_packet_address >> 3; +// eDebug("line %d, framing code: %02x, M=%02x, Y=%02x", line_offset, framing_code, M, Y); + + if (m_Y == 0) /* page header */ + { + m_C = 0; + + m_S1 = decode_hamming_84(data + 2); /* S1 */ + int S2C4 = decode_hamming_84(data + 3); + + m_S2 = S2C4 & 7; + m_C |= (S2C4 & 8) ? (1<<4) : 0; + + m_S3 = decode_hamming_84(data + 4); + + int S4C5C6 = decode_hamming_84(data + 5); + + m_S4 = S4C5C6 & 3; + m_C |= (S4C5C6 & 0xC) << 3; + + m_C |= decode_hamming_84(data + 6) << 7; + m_C |= decode_hamming_84(data + 7) << 11; + + /* page on the same magazine? end current page. */ + if ((m_M == m_page_M) && (m_page_open)) + { + handlePageEnd(); + m_page_open = 0; + } + + m_X = decode_hamming_84(data+1) * 0x10 + decode_hamming_84(data); + + /* correct page on correct magazine? open page. */ + if ((m_M == m_page_M) && (m_X == m_page_X)) + { + handlePageStart(); + m_page_open = 1; + handleLine(data + 8, 32); + } + } else + { + /* data for the selected page? */ + if ((m_M == m_page_M) && m_page_open) + handleLine(data, 40); + } + } } int eDVBTeletextParser::start(int pid) { + m_page_open = 0; + if (m_pes_reader) return m_pes_reader->start(pid); else return -1; } + +void eDVBTeletextParser::handlePageStart() +{ + if (m_C & (1<<4)) /* erase flag set */ + m_subtitle_page.clear(); +} + +void eDVBTeletextParser::handleLine(unsigned char *data, int len) +{ + if (!m_Y) /* first line is page header, we don't need that. */ + return; + + int last_was_white = 1, color = -1; + + std::string text; + + for (int i=0; i= 0x20)) + { + text += b; + last_was_white = b == ' '; + } + } + } + addSubtitleString(color, text); +} + +void eDVBTeletextParser::handlePageEnd() +{ + addSubtitleString(-1, ""); /* end last line */ + sendSubtitlePage(); /* send assembled subtitle page to display */ +} + +void eDVBTeletextParser::setPage(int page) +{ + m_page_M = (page >> 8) & 7; /* magazine to look for */ + m_page_X = page & 0xFF; /* page number */ +} + +void eDVBTeletextParser::addSubtitleString(int color, const std::string &string) +{ + if ((color != m_subtitle_color) && !m_subtitle_text.empty()) + { + m_subtitle_page.m_elements.push_back(eDVBTeletextSubtitlePageElement(gRGB(0, 0xff, 0), m_subtitle_text)); + m_subtitle_text = ""; + } else if (!m_subtitle_text.empty() && m_subtitle_text[m_subtitle_text.size()-1] != ' ') + m_subtitle_text += " "; + + m_subtitle_color = color; + m_subtitle_text += string; +} + +void eDVBTeletextParser::sendSubtitlePage() +{ + eDebug("subtitle page:"); + for (unsigned int i = 0; i < m_subtitle_page.m_elements.size(); ++i) + eDebug("%s", m_subtitle_page.m_elements[i].m_text.c_str()); +} diff --git a/lib/dvb/teletext.h b/lib/dvb/teletext.h index 9fa1e2ea..5b4a9703 100644 --- a/lib/dvb/teletext.h +++ b/lib/dvb/teletext.h @@ -4,19 +4,58 @@ #include #include #include +#include + +struct eDVBTeletextSubtitlePageElement +{ + gRGB m_color; + std::string m_text; + eDVBTeletextSubtitlePageElement(const gRGB &color, const std::string &text) + : m_color(color), m_text(text) + { + } +}; + +struct eDVBTeletextSubtitlePage +{ + pts_t m_pts; + int m_timeout; /* in pts */ + std::vector m_elements; + + void clear() { m_elements.clear(); } +}; class eDVBTeletextParser: public iObject, public ePESParser, public Object { DECLARE_REF(eDVBTeletextParser); public: eDVBTeletextParser(iDVBDemux *demux); + virtual ~eDVBTeletextParser(); int start(int pid); + void setPage(int page); private: void processPESPacket(__u8 *pkt, int len); ePtr m_pes_reader; ePtr m_read_connection; + + eDVBTeletextSubtitlePage m_subtitle_page; + + int m_M, m_Y, m_X, m_S1, m_S2, m_S3, m_S4, m_C; + + int m_page_M, m_page_X, m_page_open; + + void handlePageStart(); + void handleLine(unsigned char *line, int len); + void handlePageEnd(); + + std::string m_subtitle_text; + int m_subtitle_color; + + void addSubtitleString(int color, const std::string &string); + + void sendSubtitlePage(); }; #endif -- 2.30.2