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WIP offset estimation

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This commit is contained in:
Stepland 2023-07-06 01:11:16 +02:00
parent edbf362dd8
commit efe64cabaf
2 changed files with 58 additions and 18 deletions
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55
src/guess_tempo.cpp
View File

@ -24,12 +24,12 @@
#include "aubio_cpp.hpp"
#include "special_numeric_types.hpp"
std::vector<BPMCandidate> guess_tempo(const std::filesystem::path& audio) {
std::vector<TempoCandidate> guess_tempo(const std::filesystem::path& audio) {
feis::InputSoundFile music;
music.open_from_path(audio);
const auto onsets = detect_onsets(music);
estimate_bpm(onsets, music.getSampleRate());
// estimate offsets
const auto bpm_candidates = estimate_bpm(onsets, music.getSampleRate());
return estimate_offset(bpm_candidates, music);
}
std::set<std::size_t> detect_onsets(feis::InputSoundFile& music) {
@ -63,10 +63,11 @@ std::set<std::size_t> detect_onsets(feis::InputSoundFile& music) {
}
void estimate_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate) {
std::vector<BPMFitness> estimate_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate) {
const auto broad_fitness = broad_interval_test(onsets, sample_rate);
const auto corrected_fitness = correct_bias(broad_fitness);
const auto interval_candidates = narrow_interval_test(broad_fitness, corrected_fitness, onsets, sample_rate);
auto interval_candidates = narrow_interval_test(broad_fitness, corrected_fitness, onsets, sample_rate);
return select_bpm_candidates(interval_candidates, onsets, sample_rate);
}
const float min_tested_bpm = 89.f;
@ -130,7 +131,9 @@ std::vector<IntervalFitness> fitness_of_interval_range(const std::set<std::size_
const auto second_half_interval = tested_interval - first_half_interval;
confidence.head(first_half_interval) += evidence_cache.tail(first_half_interval) / 2;
confidence.tail(second_half_interval) += evidence_cache.head(second_half_interval) / 2;
fitness_values.push_back({tested_interval, confidence.maxCoeff()});
Eigen::Index max_index;
const auto fitness = confidence.maxCoeff(&max_index);
fitness_values.push_back({tested_interval, fitness, static_cast<std::size_t>(max_index)});
}
return fitness_values;
}
@ -228,8 +231,8 @@ std::vector<IntervalFitness> narrow_interval_test(
std::vector<BPMFitness> select_bpm_candidates(
std::vector<IntervalFitness>& interval_candidates,
const std::size_t sample_rate,
const std::set<std::size_t>& onsets
const std::set<std::size_t>& onsets,
const std::size_t sample_rate
) {
// Bram van de Wetering's original paper [BvdW] :
// "BPM candidates that differ by less than 0.1 from a multiple of a
@ -281,9 +284,10 @@ std::vector<BPMFitness> select_bpm_candidates(
}
if (diff < 0.05f) {
const auto rounded_bpm_fitness = fitness_of_bpm(onsets, sample_rate, rounded_bpm);
if (rounded_bpm_fitness > 0.99f * candidate.fitness) {
if (rounded_bpm_fitness.fitness > 0.99f * candidate.fitness) {
candidate.bpm = rounded_bpm;
candidate.fitness = rounded_bpm_fitness;
candidate.fitness = rounded_bpm_fitness.fitness;
candidate.max_onset = rounded_bpm_fitness.max_onset;
}
}
}
@ -305,7 +309,7 @@ std::vector<BPMFitness> select_bpm_candidates(
return bpm_candidates;
}
float fitness_of_bpm(
Fitness fitness_of_bpm(
const std::set<std::size_t>& onsets,
const std::size_t sample_rate,
const Fraction BPM
@ -330,5 +334,32 @@ float fitness_of_bpm(
const auto second_half_interval = rounded_interval - first_half_interval;
confidence.head(first_half_interval) += evidence_cache.tail(first_half_interval) / 2;
confidence.tail(second_half_interval) += evidence_cache.head(second_half_interval) / 2;
return confidence.maxCoeff();
Eigen::Index max_index;
const auto fitness = confidence.maxCoeff(&max_index);
return {fitness, static_cast<std::size_t>(max_index)};
}
std::vector<TempoCandidate> estimate_offset(const std::vector<BPMFitness>& bpm_candidates, feis::InputSoundFile& music) {
std::vector<TempoCandidate> result;
result.reserve(bpm_candidates.size());
music.seek(0);
const std::size_t mono_samples = music.getSampleCount() / music.getChannelCount();
std::vector<float> amplitude(mono_samples);
const std::size_t chunk_size = 4096 * music.getChannelCount();
std::size_t read;
std::vector<sf::Int16> buffer(chunk_size);
do {
read = music.read(buffer.data(), chunk_size);
for (std::size_t i = 0; i < read / music.getChannelCount(); i++) {
float downmixed_sample = 0;
for (std::size_t channel = 0; channel < music.getChannelCount(); channel++) {
downmixed_sample += buffer[i * music.getChannelCount() + channel];
}
amplitude[i] = downmixed_sample / channel_count;
}
} while ( read == chunk_size );
for (const auto& bpm_candidate : bpm_candidates) {
const Fraction initial_offset_estimate = Fraction{bpm_candidate.max_onset, music.getSampleRate()};
}
}

21
src/guess_tempo.hpp
View File

@ -14,24 +14,31 @@
struct IntervalFitness {
std::size_t interval;
float fitness;
std::size_t max_onset;
};
struct BPMFitness {
Fraction bpm;
float fitness;
std::size_t max_onset;
};
struct BPMCandidate {
struct Fitness {
float fitness;
std::size_t max_onset;
};
struct TempoCandidate {
Fraction bpm;
std::size_t offset;
float fitness;
};
std::vector<BPMCandidate> guess_tempo(const std::filesystem::path& audio);
std::vector<TempoCandidate> guess_tempo(const std::filesystem::path& audio);
std::set<std::size_t> detect_onsets(feis::InputSoundFile& music);
void estimate_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate);
std::vector<BPMFitness> estimate_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate);
std::vector<IntervalFitness> broad_interval_test(const std::set<std::size_t>& onsets, const std::size_t sample_rate);
std::vector<IntervalFitness> fitness_of_interval_range(
const std::set<std::size_t>& onsets,
@ -49,7 +56,9 @@ std::vector<IntervalFitness> narrow_interval_test(
);
std::vector<BPMFitness> select_bpm_candidates(
std::vector<IntervalFitness>& interval_candidates,
const std::size_t sample_rate,
const std::set<std::size_t>& onsets
const std::set<std::size_t>& onsets,
const std::size_t sample_rate
);
float fitness_of_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate, const Fraction BPM);
Fitness fitness_of_bpm(const std::set<std::size_t>& onsets, const std::size_t sample_rate, const Fraction BPM);
std::vector<TempoCandidate> estimate_offset(const std::vector<BPMFitness>& bpm_candidates, feis::InputSoundFile& music);