diff options
| -rw-r--r-- | etisnoop.cpp | 121 |
1 files changed, 117 insertions, 4 deletions
diff --git a/etisnoop.cpp b/etisnoop.cpp index ce69746..9d79a45 100644 --- a/etisnoop.cpp +++ b/etisnoop.cpp @@ -49,6 +49,68 @@ struct FIG int len; }; +class WatermarkDecoder +{ + public: + void push_confind_bit(bool confind) + { + // The ConfInd of FIG 0/10 contains the CRC-DABMUX and ODR-DabMux watermark + m_confind_bits.push_back(confind); + } + + std::string calculate_watermark() + { + // First try to find the 0x55 0x55 sync in the waternark data + size_t bit_ix; + int alternance_count = 0; + bool last_bit = 1; + for (bit_ix = 0; bit_ix < m_confind_bits.size(); bit_ix++) { + if (alternance_count == 16) { + break; + } + else { + if (last_bit != m_confind_bits[bit_ix]) { + last_bit = m_confind_bits[bit_ix]; + alternance_count++; + } + else { + alternance_count = 0; + last_bit = 1; + } + } + + } + + printf("Found SYNC at offset %zu out of %zu\n", bit_ix - alternance_count, m_confind_bits.size()); + + std::stringstream watermark_ss; + + uint8_t b = 0; + size_t i = 0; + while (bit_ix < m_confind_bits.size()) { + + b |= m_confind_bits[bit_ix] << (7 - i); + + if (i == 7) { + watermark_ss << (char)b; + + b = 0; + i = 0; + } + else { + i++; + } + + bit_ix += 2; + } + + return watermark_ss.str(); + } + + private: + std::vector<bool> m_confind_bits; +}; + class FIGalyser { public: @@ -146,6 +208,7 @@ struct eti_analyse_config_t { bool ignore_error; std::map<int, DabPlusSnoop> streams_to_decode; bool analyse_fic_carousel; + bool decode_watermark; }; // Globals @@ -163,6 +226,7 @@ void printbuf(string header, string desc=""); void decodeFIG(FIGalyser &figs, + WatermarkDecoder &wm_decoder, unsigned char* figdata, unsigned char figlen, unsigned short int figtype, @@ -208,7 +272,8 @@ void usage(void) "\n" " -v increase verbosity (can be given more than once)\n" " -d N decode subchannel N into .dabp, .aac and .wav files\n" - " -f analyse FIC carousel\n"); + " -f analyse FIC carousel\n" + " -w decode CRC-DABMUX and ODR-DabMux watermark.\n"); } int main(int argc, char *argv[]) @@ -221,9 +286,10 @@ int main(int argc, char *argv[]) verbosity = 0; bool ignore_error = false; bool analyse_fic_carousel = false; + bool decode_watermark = false; while(ch != -1) { - ch = getopt_long(argc, argv, "d:efhvi:", longopts, &index); + ch = getopt_long(argc, argv, "d:efhvwi:", longopts, &index); switch (ch) { case 'd': { @@ -244,6 +310,9 @@ int main(int argc, char *argv[]) case 'v': verbosity++; break; + case 'w': + decode_watermark = true; + break; case 'h': usage(); return 1; @@ -269,7 +338,8 @@ int main(int argc, char *argv[]) .etifd = etifd, .ignore_error = ignore_error, .streams_to_decode = streams_to_decode, - .analyse_fic_carousel = analyse_fic_carousel + .analyse_fic_carousel = analyse_fic_carousel, + .decode_watermark = decode_watermark }; eti_analyse(config); fclose(etifd); @@ -307,6 +377,8 @@ int eti_analyse(eti_analyse_config_t& config) printf("?\n"); } + WatermarkDecoder wm_decoder; + while (running) { int ret = get_eti_frame(config.etifd, stream_type, p); @@ -557,7 +629,7 @@ int eti_analyse(eti_analyse_config_t& config) figlen = fig[0] & 0x1F; sprintf(sdesc, "FIG %d [%d bytes]", figtype, figlen); printbuf(sdesc, 3, fig+1, figlen); - decodeFIG(figs, fig+1, figlen, figtype, 4); + decodeFIG(figs, wm_decoder, fig+1, figlen, figtype, 4); fig += figlen + 1; figcount += figlen + 1; if (figcount >= 29) @@ -650,10 +722,16 @@ int eti_analyse(eti_analyse_config_t& config) it->second.close(); } + if (config.decode_watermark) { + std::string watermark(wm_decoder.calculate_watermark()); + printf("Watermark:\n %s\n", watermark.c_str()); + } + return 0; } void decodeFIG(FIGalyser &figs, + WatermarkDecoder &wm_decoder, unsigned char* f, unsigned char figlen, unsigned short int figtype, @@ -874,6 +952,41 @@ void decodeFIG(FIGalyser &figs, } } break; + case 10: // FIG 0/10 + { + /* TODO verify and convert from MJD representation + uint32_t MJD = ((f[1] & 0x7) << 10) | + ((uint32_t)(f[2]) << 2) | + (f[3] >> 6); + */ + + //bool RFU = f[1] >> 7; + + bool LSI = f[3] & 0x20; + bool ConfInd = f[3] & 0x10; + wm_decoder.push_confind_bit(ConfInd); + bool UTC = f[3] & 0x8; + + uint8_t hours = ((f[3] & 0x7) << 2) | + ( f[4] >> 6); + + uint8_t minutes = f[4] & 0x3f; + + if (UTC) { + uint8_t seconds = f[5] >> 2; + uint16_t milliseconds = ((uint16_t)(f[5] & 0x2) << 8) | f[6]; + + sprintf(desc, "FIG %d/%d(long): LSI %u, ConfInd %u, UTC Time: %02d:%02d:%02d.%d", + figtype, ext, LSI, ConfInd, hours, minutes, seconds, milliseconds); + printbuf(desc, indent+1, NULL, 0); + } + else { + sprintf(desc, "FIG %d/%d(short): LSI %u, ConfInd %u, UTC Time: %02d:%02d", + figtype, ext, LSI, ConfInd, hours, minutes); + printbuf(desc, indent+1, NULL, 0); + } + } + break; case 13: // FIG 0/13 { uint32_t SId; |