73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#pragma once
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#include "ReplayGainAnalyzer.hxx"
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#include "Chrono.hxx"
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#include <span>
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constexpr auto mixramp_volumes = std::array{
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-90., -60., -40., -30., -24., -21., -18.,
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-15., -12., -9., -6., -3., 0., 3., 6.,
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};
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struct MixRampItem {
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FloatDuration time;
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double volume;
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constexpr bool operator==(const MixRampItem &other) const noexcept {
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return time == other.time && volume == other.volume;
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}
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constexpr bool operator!=(const MixRampItem &other) const noexcept {
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return !(*this == other);
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}
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};
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using MixRampArray = std::array<MixRampItem, mixramp_volumes.size()>;
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struct MixRampData {
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MixRampArray start, end;
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constexpr MixRampData() noexcept:start{}, end{} {
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for (std::size_t i = 0; i < mixramp_volumes.size(); ++i) {
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start[i].time = end[i].time = FloatDuration{-1};
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start[i].volume = end[i].volume = mixramp_volumes[i];
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}
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}
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void Add(MixRampItem item) noexcept;
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};
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/**
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* Analyze a 44.1 kHz / stereo / float32 audio stream and calculate
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* MixRamp tags.
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*/
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class MixRampAnalyzer {
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static constexpr std::size_t chunk_duration_fraction = 10;
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static constexpr std::size_t chunk_frames =
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ReplayGainAnalyzer::SAMPLE_RATE / chunk_duration_fraction;
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static constexpr FloatDuration chunk_duration{1.0 / chunk_duration_fraction};
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WindowReplayGainAnalyzer gain_analyzer;
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MixRampData result;
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std::size_t chunk_number = 0;
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std::size_t chunk_fill = 0;
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public:
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void Process(std::span<const ReplayGainAnalyzer::Frame> src) noexcept;
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FloatDuration GetTime() const noexcept {
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return chunk_number * chunk_duration;
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}
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const auto &GetResult() const noexcept {
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return result;
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}
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};
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