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added CRC check of payload

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This commit is contained in:
Ahmet Inan 2021-06-10 09:33:26 +02:00
commit cc3e9cc10f
3 changed files with 36 additions and 16 deletions
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21
encode.cc
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@ -36,7 +36,8 @@ struct Encoder
static const int mls2_poly = 0b100101010001;
DSP::WritePCM<value> *pcm;
DSP::FastFourierTransform<symbol_len, cmplx, 1> bwd;
CODE::CRC<uint16_t> crc;
CODE::CRC<uint16_t> crc0;
CODE::CRC<uint32_t> crc1;
CODE::BoseChaudhuriHocquenghemEncoder<255, 71> bchenc;
cmplx fdom[symbol_len];
cmplx tdom[symbol_len];
@ -109,8 +110,8 @@ struct Encoder
uint8_t data[9] = { 0 }, parity[23] = { 0 };
for (int i = 0; i < 55; ++i)
CODE::set_be_bit(data, i, (md>>i)&1);
crc.reset();
uint16_t cs = crc(md << 9);
crc0.reset();
uint16_t cs = crc0(md << 9);
for (int i = 0; i < 16; ++i)
CODE::set_be_bit(data, i+55, (cs>>i)&1);
bchenc(data, parity);
@ -130,7 +131,7 @@ struct Encoder
symbol();
}
Encoder(DSP::WritePCM<value> *pcm, uint8_t *inp, int freq_off, uint64_t call_sign) :
pcm(pcm), crc(0xA8F4), bchenc({
pcm(pcm), crc0(0xA8F4), crc1(0xD419CC15), bchenc({
0b100011101, 0b101110111, 0b111110011, 0b101101001,
0b110111101, 0b111100111, 0b100101011, 0b111010111,
0b000010011, 0b101100101, 0b110001011, 0b101100011,
@ -146,6 +147,11 @@ struct Encoder
schmidl_cox();
meta_data((call_sign << 8) | 2);
pilot_block();
crc1.reset();
for (int i = 0; i < (data_bits-32)/8; ++i)
crc1(inp[i]);
for (int i = 0; i < 4; ++i)
inp[(data_bits-32)/8+i] = (crc1() >> (8*i)) & 255;
for (int j = 0; j < data_rows; ++j) {
for (int i = 0; i < data_cols; ++i) {
value tmp[Mod::BITS];
@ -225,9 +231,10 @@ int main(int argc, char **argv)
std::cerr << "Couldn't open file \"" << input_name << "\" for reading." << std::endl;
return 1;
}
const int length = 64800 / 8;
uint8_t *input_data = new uint8_t[length];
for (int i = 0; i < length; ++i)
const int code_len = 64800 / 8;
const int data_len = code_len - 32 / 8;
uint8_t *input_data = new uint8_t[code_len];
for (int i = 0; i < data_len; ++i)
input_data[i] = input_file.get();
DSP::WriteWAV<value> output_file(output_name, output_rate, output_bits, output_chan);