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M17 - LSF Encode (WIP); Initial FSN Bug Fix; Misc;

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lwvmobile
2024-03-05 22:23:08 -05:00
parent 16b950d5a0
commit 7754123e30
1 changed files with 179 additions and 20 deletions
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199
src/m17.c
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@@ -811,6 +811,124 @@ void processM17LSF(dsd_opts * opts, dsd_state * state)
} //end processM17LSF
// void processM17LSF_debug(dsd_opts * opts, dsd_state * state, uint8_t * m17_rnd_bits)
void processM17LSF_debug(dsd_opts * opts, dsd_state * state, uint8_t * m17_depunc)
{
//NOTE: Having run a full debug on all steps, I am convinced that the number of punctures
//renders the current convolutional decoder useless to fix the holes in an LSF frame
//Skipping to the deconvolution step renders the correct frame info and crc value
//We can still send the full LSF as intended over IP frame or RF without this step
//TODO: Switch to M17 Viterbi Decoder for better performance
int i, x; UNUSED(x);
uint8_t m17_int_bits[368]; //368 bits that are still interleaved
uint8_t m17_bits[368]; //368 bits that have been de-interleaved and de-scramble
// uint8_t m17_depunc[488]; //488 bits after depuncturing
memset (m17_int_bits, 0, sizeof(m17_int_bits));
memset (m17_bits, 0, sizeof(m17_bits));
// memset (m17_depunc, 0, sizeof(m17_depunc));
//descramble the frame
// for (i = 0; i < 368; i++)
// m17_int_bits[i] = (m17_rnd_bits[i] ^ m17_scramble[i]) & 1;
//deinterleave the bit array using Quadratic Permutation Polynomial
//function π(x) = (45x + 92x^2 ) mod 368
// for (i = 0; i < 368; i++)
// {
// x = ((45*i)+(92*i*i)) % 368;
// m17_bits[i] = m17_int_bits[x];
// }
//P1 Depuncture
// x = 0;
// for (i = 0; i < 488; i++)
// {
// if (p1[i%61] == 1)
// m17_depunc[i] = m17_bits[x++];
// else m17_depunc[i] = 0;
// }
//setup the convolutional decoder
uint8_t temp[488];
uint8_t s0;
uint8_t s1;
uint8_t m_data[30];
uint8_t trellis_buf[240]; //30*8 = 240
memset (trellis_buf, 0, sizeof(trellis_buf));
memset (temp, 0, sizeof (temp));
memset (m_data, 0, sizeof (m_data));
for (i = 0; i < 488; i++)
temp[i] = m17_depunc[i] << 1;
CNXDNConvolution_start();
for (i = 0; i < 244; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 240);
//244/8 = 30, last 4 (244-248) are trailing zeroes
for(i = 0; i < 30; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
memset (state->m17_lsf, 0, sizeof(state->m17_lsf));
memcpy (state->m17_lsf, trellis_buf, 240);
uint8_t lsf_packed[30];
memset (lsf_packed, 0, sizeof(lsf_packed));
//need to pack bytes for the sw5wwp variant of the crc (might as well, may be useful in the future)
for (i = 0; i < 30; i++)
lsf_packed[i] = (uint8_t)ConvertBitIntoBytes(&state->m17_lsf[i*8], 8);
uint16_t crc_cmp = crc16m17(lsf_packed, 28);
uint16_t crc_ext = (uint16_t)ConvertBitIntoBytes(&state->m17_lsf[224], 16);
int crc_err = 0;
if (crc_cmp != crc_ext) crc_err = 1;
if (crc_err == 0)
M17decodeLSF(state);
if (opts->payload == 1)
{
fprintf (stderr, "\n LSF: ");
for (i = 0; i < 30; i++)
{
if (i == 15) fprintf (stderr, "\n ");
fprintf (stderr, "[%02X]", lsf_packed[i]);
}
}
//debug
// fprintf (stderr, " E-%04X; C-%04X (CRC CHK)", crc_ext, crc_cmp);
if (crc_err == 1) fprintf (stderr, " CRC ERR");
//ending linebreak
// fprintf (stderr, "\n");
} //end processM17LSF_debug
//debug M17STR for the encoder to pass bits into
void processM17STR_debug(dsd_opts * opts, dsd_state * state, uint8_t * m17_rnd_bits)
{
@@ -976,8 +1094,10 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
short voice1[nsam]; //read in xxx ms of audio from input source
short voice2[nsam]; //read in xxx ms of audio from input source
int fsn, eot = 0; //frame sequence number and eot bit
int lich_cnt = 0; //lich frame number counter
//frame sequence number and eot bit (fixes initial FSN of 17152)
uint8_t fsn = 0;
uint8_t eot = 0;
uint8_t lich_cnt = 0; //lich frame number counter
uint8_t lsf_chunk[6][48]; //40 bit chunks of link information spread across 6 frames
uint8_t m17_lsf[240]; //the complete LSF
@@ -1003,30 +1123,30 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
//Only if not already set as numerical value
if (dst == 0)
{
for(i = strlen((const char*)d40)-1; i >= 0; i--)
{
for(j = 0; j < 40; j++)
for(i = strlen((const char*)d40)-1; i >= 0; i--)
{
if(d40[i]==b40[j])
for(j = 0; j < 40; j++)
{
dst=dst*40+j;
break;
}
if(d40[i]==b40[j])
{
dst=dst*40+j;
break;
}
}
}
}
if (src == 0)
{
for(i = strlen((const char*)s40)-1; i >= 0; i--)
{
for(j = 0; j < 40; j++)
for(i = strlen((const char*)s40)-1; i >= 0; i--)
{
if(s40[i]==b40[j])
for(j = 0; j < 40; j++)
{
src=src*40+j;
break;
}
if(s40[i]==b40[j])
{
src=src*40+j;
break;
}
}
}
}
@@ -1060,7 +1180,47 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
//attach the crc16 bits to the end of the LSF data
for (i = 0; i < 16; i++) m17_lsf[224+i] = (crc_cmp >> 15-i) & 1;
//WIP: Craft and Send Initial LSF frame to be decoded
//LSF w/ convolutional encoding (double check array sizes)
uint8_t m17_lsfc[488]; memset (m17_lsfc, 0, sizeof(m17_lsfc)); UNUSED(m17_lsfc);
//LSF w/ P1 Puncturing
uint8_t m17_lsfp[368]; memset (m17_lsfp, 0, sizeof(m17_lsfp)); UNUSED(m17_lsfp);
//LSF w/ Interleave
uint8_t m17_lsfi[368]; memset (m17_lsfi, 0, sizeof(m17_lsfi)); UNUSED(m17_lsfi);
//LSF w/ Scrambling
uint8_t m17_lsfs[368]; memset (m17_lsfs, 0, sizeof(m17_lsfs)); UNUSED(m17_lsfs);
//Use the convolutional encoder to encode the voice / data stream
simple_conv_encoder (m17_lsf, m17_lsfc, 244);
//P1 puncture
x = 0;
for (i = 0; i < 488; i++)
{
if (p1[i%61] == 1)
m17_lsfp[x++] = m17_lsfc[i];
}
//interleave the bit array using Quadratic Permutation Polynomial
//function π(x) = (45x + 92x^2 ) mod 368
for (i = 0; i < 368; i++)
{
x = ((45*i)+(92*i*i)) % 368;
m17_lsfi[x] = m17_lsfp[i];
}
//scramble/randomize the frame
for (i = 0; i < 368; i++)
m17_lsfs[i] = (m17_lsfi[i] ^ m17_scramble[i]) & 1;
fprintf (stderr, "\n M17 Stream (ENCODER): ");
processM17LSF_debug(opts, state, m17_lsfc);
while (!exitflag) //while the software is running
{
//read some audio samples from source and load them into an audio buffer
@@ -1352,7 +1512,7 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
//Start working on converting the bitsream to an audio stream
//convert to symbols @ 4800 bps
int output_symbols[192]; memset (output_symbols, 0, sizeof(output_symbols));
int output_symbols[192]; memset (output_symbols, 0, sizeof(output_symbols)); UNUSED(output_symbols);
for (i = 0; i < 192; i++)
output_symbols[i] = symbol_map[output_dibits[i]];
@@ -1363,7 +1523,6 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
// if (i%24 == 0) fprintf (stderr, "\n");
// fprintf (stderr, " %d", output_symbols[i]);
// }
UNUSED(output_symbols);
//TODO: symbols to audio
@@ -1482,7 +1641,6 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
nonce[12] = rand() & 0xFF;
nonce[13] = rand() & 0xFF;
//load the nonce from packed bytes to a bitwise iv array
memset(iv, 0, sizeof(iv));
k = 0;
@@ -1491,6 +1649,7 @@ void encodeM17STR(dsd_opts * opts, dsd_state * state)
for (i = 0; i < 8; i++)
iv[k++] = (nonce[j] >> 7-i)&1;
}
//if AES enc employed, insert the iv into LSF
if (lsf_et == 2)
{