104 lines
2.7 KiB
C++
104 lines
2.7 KiB
C++
/***
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Oak - Non-Linear Video Editor
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Copyright (C) 2026 Oak Team
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "audiolevelmeter.h"
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#include <algorithm>
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#include <cmath>
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#include "common/decibel.h"
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namespace olive
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{
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AudioLevelMeter::Stats
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AudioLevelMeter::AnalyzeSampleBuffer(const core::SampleBuffer &samples)
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{
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Stats stats;
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const int channel_count = samples.channel_count();
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const size_t sample_count = samples.sample_count();
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stats.channels.resize(channel_count);
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if (!channel_count || !sample_count) {
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return stats;
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}
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double total_square = 0.0;
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size_t total_samples = 0;
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for (int channel = 0; channel < channel_count; channel++) {
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const float *channel_data = samples.data(channel);
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double peak = 0.0;
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double square_sum = 0.0;
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for (size_t sample = 0; sample < sample_count; sample++) {
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const double value = channel_data[sample];
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const double abs_value = std::abs(value);
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peak = std::max(peak, abs_value);
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square_sum += value * value;
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}
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const double mean_square = square_sum / static_cast<double>(sample_count);
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const double rms = std::sqrt(mean_square);
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ChannelStats channel_stats;
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channel_stats.peak_linear = peak;
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channel_stats.peak_db = LinearToDb(peak);
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channel_stats.rms_linear = rms;
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channel_stats.rms_db = LinearToDb(rms);
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channel_stats.vu_db = channel_stats.rms_db;
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stats.channels[channel] = channel_stats;
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stats.max_peak_linear = std::max(stats.max_peak_linear, peak);
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total_square += square_sum;
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total_samples += sample_count;
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}
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stats.silence = qFuzzyIsNull(stats.max_peak_linear);
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stats.integrated_lufs = PowerToLufs(
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total_square / static_cast<double>(total_samples));
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return stats;
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}
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double AudioLevelMeter::LinearToDb(double linear)
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{
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if (linear <= 0.0) {
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return Decibel::MINIMUM;
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}
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return Decibel::fromLinear(linear);
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}
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double AudioLevelMeter::PowerToLufs(double mean_square)
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{
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if (mean_square <= 0.0) {
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return Decibel::MINIMUM;
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}
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// BS.1770 loudness uses K-weighted mean square. This first pass stores the
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// compatible unit and can be extended with K-weighting without changing UI.
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return -0.691 + 10.0 * std::log10(mean_square);
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}
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}
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