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Commit e4b7b8e6 authored by Stefan Westerfeld's avatar Stefan Westerfeld
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Make long block decoder reliable for short clips. 

Signed-off-by: Stefan Westerfeld's avatarStefan Westerfeld <stefan@space.twc.de>
parent 1470b5d5
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Showing with 78 additions and 35 deletions
src/wmget.cc
View file @ e4b7b8e6
......@@ -250,10 +250,11 @@ private:
}
}
double
sync_decode (const WavData& wav_data, const size_t start_frame, const vector<float>& fft_out_db, ConvBlockType *block_type)
sync_decode (const WavData& wav_data, const size_t start_frame, const vector<float>& fft_out_db, ConvBlockType *block_type, int *len)
{
double sync_quality = 0;
int zbits = 0, lbits = 0;
size_t n_bands = Params::max_band - Params::min_band + 1;
for (int bit = 0; bit < Params::sync_bits; bit++)
{
......@@ -264,14 +265,26 @@ private:
const int index = (start_frame * wav_data.n_channels() + ch) * n_bands;
for (size_t i = 0; i < up[bit].size(); i++)
{
if (fft_out_db[index + up[bit][i]] < -90 && fft_out_db[index + down[bit][i]] < -90)
{
zbits++;
}
else
{
umag += fft_out_db[index + up[bit][i]];
dmag += fft_out_db[index + down[bit][i]];
lbits++;
}
}
}
/* convert avoiding bias, raw_bit < 0 => 0 bit received; raw_bit > 0 => 1 bit received */
double raw_bit;
if (umag < dmag)
if (umag == 0 || dmag == 0)
{
raw_bit = 0;
}
else if (umag < dmag)
{
raw_bit = 1 - umag / dmag;
}
......@@ -287,6 +300,7 @@ private:
sync_quality /= Params::sync_bits;
sync_quality = normalize_sync_quality (sync_quality);
*len = lbits;
if (sync_quality < 0)
{
*block_type = ConvBlockType::b;
......@@ -303,6 +317,7 @@ public:
size_t index;
double quality;
ConvBlockType block_type;
int len = 0;
};
vector<Score>
search (const WavData& wav_data, BlockLength block_length)
......@@ -341,9 +356,10 @@ public:
if ((start_frame + total_frame_count) * wav_data.n_channels() * n_bands < fft_db.size())
{
ConvBlockType block_type;
double quality = sync_decode (wav_data, start_frame, fft_db, &block_type);
int len;
double quality = sync_decode (wav_data, start_frame, fft_db, &block_type, &len);
// printf ("%zd %f\n", sync_index, quality);
sync_scores.emplace_back (Score { sync_index, quality, block_type });
sync_scores.emplace_back (Score { sync_index, quality, block_type, len });
}
}
}
......@@ -366,9 +382,37 @@ public:
const double strength = Params::water_delta * 1000;
const double sync_threshold1 = strength > 7.5 ? 0.4 : 0.5;
/* n-best-search */
struct NBest {
size_t i;
int len;
};
vector<NBest> n_best;
for (size_t i = 0; i < sync_scores.size(); i++)
{
// printf ("%zd %f\n", sync_scores[i].index, sync_scores[i].quality);
if (sync_scores[i].quality > sync_threshold1)
{
double q_last = -1;
double q_next = -1;
if (i > 0)
q_last = sync_scores[i - 1].quality;
if (i + 1 < sync_scores.size())
q_next = sync_scores[i + 1].quality;
if (sync_scores[i].quality > q_last && sync_scores[i].quality > q_next)
{
n_best.push_back ({ i, sync_scores[i].len });
}
}
}
std::sort (n_best.begin(), n_best.end(), [](NBest& nb1, NBest& nb2) { return nb1.len > nb2.len; });
if (n_best.size() > 5)
n_best.resize (5);
for (auto n : n_best)
{
size_t i = n.i;
//printf ("%d %zd %f %d\n", int (block_length), sync_scores[i].index, sync_scores[i].quality, sync_scores[i].len);
if (sync_scores[i].quality > sync_threshold1)
{
double q_last = -1;
......@@ -397,7 +441,8 @@ public:
if (fft_db.size())
{
ConvBlockType block_type;
double q = sync_decode (wav_data, 0, fft_db, &block_type);
int len;
double q = sync_decode (wav_data, 0, fft_db, &block_type, &len);
if (q > best_quality)
{
......@@ -479,7 +524,7 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern)
int match_count = 0, total_count = 0, sync_match = 0;
SyncFinder sync_finder;
vector<SyncFinder::Score> sync_scores = sync_finder.search (wav_data, SyncFinder::BlockLength::NORMAL);
vector<SyncFinder::Score> sync_scores; // FIXME = sync_finder.search (wav_data, SyncFinder::BlockLength::NORMAL);
auto report_pattern = [&] (SyncFinder::Score sync_score, const vector<int>& bit_vec, float decode_error)
{
......@@ -603,29 +648,6 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern)
report_pattern (score_all, bit_vec, decode_error);
}
if (!orig_pattern.empty())
{
printf ("match_count %d %d\n", match_count, total_count);
/* search sync markers at typical positions */
const int expect0 = Params::frames_pad_start * Params::frame_size;
const int expect_step = (mark_sync_frame_count() + mark_data_frame_count()) * Params::frame_size;
const int expect_end = frame_count (wav_data) * Params::frame_size;
for (int expect_index = expect0; expect_index + expect_step < expect_end; expect_index += expect_step)
{
for (auto sync_score : sync_scores)
{
if (abs (int (sync_score.index + Params::test_cut) - expect_index) < Params::frame_size / 2)
{
sync_match++;
break;
}
}
}
printf ("sync_match %d %zd\n", sync_match, sync_scores.size());
}
// L-blocks
SyncFinder sync_finder_l;
vector<SyncFinder::Score> sync_scores_l = sync_finder.search (wav_data, SyncFinder::BlockLength::LONG);
......@@ -643,8 +665,6 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern)
break;
}
const int seconds = sync_score.index / wav_data.sample_rate();
printf ("pattern %2d:%02d L:%s %.3f\n", seconds / 60, seconds % 60, block_str.c_str(), sync_score.quality);
const size_t count = mark_sync_frame_count() + mark_data_frame_count();
const size_t index = sync_score.index;
auto fft_range_out1 = fft_analyzer.fft_range (wav_data.samples(), index, count);
......@@ -672,8 +692,31 @@ decode_and_report (const WavData& wav_data, const string& orig_pattern)
float decode_error = 0;
vector<int> bit_vec = conv_decode_soft (ConvBlockType::ab, normalize_soft_bits (raw_bit_vec), &decode_error);
printf (" => %s %f\n", bit_vec_to_str (bit_vec).c_str(), decode_error);
printf ("LLL ");
report_pattern (sync_score, bit_vec, decode_error);
}
}
if (!orig_pattern.empty())
{
printf ("match_count %d %d\n", match_count, total_count);
/* search sync markers at typical positions */
const int expect0 = Params::frames_pad_start * Params::frame_size;
const int expect_step = (mark_sync_frame_count() + mark_data_frame_count()) * Params::frame_size;
const int expect_end = frame_count (wav_data) * Params::frame_size;
for (int expect_index = expect0; expect_index + expect_step < expect_end; expect_index += expect_step)
{
for (auto sync_score : sync_scores)
{
if (abs (int (sync_score.index + Params::test_cut) - expect_index) < Params::frame_size / 2)
{
sync_match++;
break;
}
}
}
printf ("sync_match %d %zd\n", sync_match, sync_scores.size());
}
return 0;
}
......
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