From 713c7585b5b4db7ca2cc4c8c50aa697512056e78 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Mon, 6 Dec 2021 10:26:32 +0100
Subject: [PATCH] pcm/MixRampAnalyzer: a MixRamp implementation
---
src/pcm/MixRampAnalyzer.cxx | 64 +++++++++++++++++++++++++++
src/pcm/MixRampAnalyzer.hxx | 86 +++++++++++++++++++++++++++++++++++++
src/pcm/meson.build | 1 +
test/RunMixRampAnalyzer.cxx | 85 ++++++++++++++++++++++++++++++++++++
test/meson.build | 11 +++++
5 files changed, 247 insertions(+)
create mode 100644 src/pcm/MixRampAnalyzer.cxx
create mode 100644 src/pcm/MixRampAnalyzer.hxx
create mode 100644 test/RunMixRampAnalyzer.cxx
diff --git a/src/pcm/MixRampAnalyzer.cxx b/src/pcm/MixRampAnalyzer.cxx
new file mode 100644
index 000000000..939d0dbe6
--- /dev/null
+++ b/src/pcm/MixRampAnalyzer.cxx
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2003-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "MixRampAnalyzer.hxx"
+#include "util/ConstBuffer.hxx"
+
+inline void
+MixRampData::Add(MixRampItem item) noexcept
+{
+ for (std::size_t i = 0; i < mixramp_volumes.size(); ++i) {
+ if (start[i].time < FloatDuration{} &&
+ item.volume >= mixramp_volumes[i])
+ start[i] = item;
+
+ if (item.volume >= mixramp_volumes[i])
+ end[i] = item;
+ }
+
+}
+
+void
+MixRampAnalyzer::Process(ConstBuffer<ReplayGainAnalyzer::Frame> src) noexcept
+{
+ while (!src.empty()) {
+ std::size_t chunk_remaining = chunk_frames - chunk_fill;
+ assert(chunk_remaining > 0);
+
+ if (chunk_remaining > src.size) {
+ gain_analyzer.Process(src);
+ chunk_fill += src.size;
+ return;
+ }
+
+ gain_analyzer.Process({src.data, chunk_remaining});
+ src.skip_front(chunk_remaining);
+
+ gain_analyzer.Flush();
+
+ const double gain = (double)gain_analyzer.GetGain();
+ const double volume = -gain;
+
+ result.Add({GetTime(), volume});
+
+ ++chunk_number;
+ chunk_fill = 0;
+ gain_analyzer = {};
+ }
+}
diff --git a/src/pcm/MixRampAnalyzer.hxx b/src/pcm/MixRampAnalyzer.hxx
new file mode 100644
index 000000000..779640d27
--- /dev/null
+++ b/src/pcm/MixRampAnalyzer.hxx
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2003-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#pragma once
+
+#include "ReplayGainAnalyzer.hxx"
+#include "Chrono.hxx"
+
+constexpr auto mixramp_volumes = std::array{
+ -90., -60., -40., -30., -24., -21., -18.,
+ -15., -12., -9., -6., -3., 0., 3., 6.,
+};
+
+struct MixRampItem {
+ FloatDuration time;
+ double volume;
+
+ constexpr bool operator==(const MixRampItem &other) const noexcept {
+ return time == other.time && volume == other.volume;
+ }
+
+ constexpr bool operator!=(const MixRampItem &other) const noexcept {
+ return !(*this == other);
+ }
+};
+
+using MixRampArray = std::array<MixRampItem, mixramp_volumes.size()>;
+
+struct MixRampData {
+ MixRampArray start, end;
+
+ constexpr MixRampData() noexcept:start{}, end{} {
+ for (std::size_t i = 0; i < mixramp_volumes.size(); ++i) {
+ start[i].time = end[i].time = FloatDuration{-1};
+ start[i].volume = end[i].volume = mixramp_volumes[i];
+ }
+ }
+
+ void Add(MixRampItem item) noexcept;
+};
+
+/**
+ * Analyze a 44.1 kHz / stereo / float32 audio stream and calculate
+ * MixRamp tags.
+ */
+class MixRampAnalyzer {
+ static constexpr std::size_t chunk_duration_fraction = 10;
+ static constexpr std::size_t chunk_frames =
+ ReplayGainAnalyzer::SAMPLE_RATE / chunk_duration_fraction;
+ static constexpr FloatDuration chunk_duration{1.0 / chunk_duration_fraction};
+
+ WindowReplayGainAnalyzer gain_analyzer;
+
+ MixRampData result;
+
+ std::size_t chunk_number = 0;
+
+ std::size_t chunk_fill = 0;
+
+public:
+ void Process(ConstBuffer<ReplayGainAnalyzer::Frame> src) noexcept;
+
+ FloatDuration GetTime() const noexcept {
+ return chunk_number * chunk_duration;
+ }
+
+ const auto &GetResult() const noexcept {
+ return result;
+ }
+};
diff --git a/src/pcm/meson.build b/src/pcm/meson.build
index 6fa0d6bc0..04860df9f 100644
--- a/src/pcm/meson.build
+++ b/src/pcm/meson.build
@@ -48,6 +48,7 @@ pcm_sources = [
'ConfiguredResampler.cxx',
'AudioCompress/compress.c',
'ReplayGainAnalyzer.cxx',
+ 'MixRampAnalyzer.cxx',
]
libsamplerate_dep = dependency('samplerate', version: '>= 0.1.3', required: get_option('libsamplerate'))
diff --git a/test/RunMixRampAnalyzer.cxx b/test/RunMixRampAnalyzer.cxx
new file mode 100644
index 000000000..652ba98f2
--- /dev/null
+++ b/test/RunMixRampAnalyzer.cxx
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2003-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "ReadFrames.hxx"
+#include "pcm/MixRampAnalyzer.hxx"
+#include "io/FileDescriptor.hxx"
+#include "util/ConstBuffer.hxx"
+#include "util/PrintException.hxx"
+
+#include <array>
+#include <memory>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main(int, char **) noexcept
+try {
+ constexpr std::size_t frame_size = sizeof(ReplayGainAnalyzer::Frame);
+
+ const FileDescriptor input_fd(STDIN_FILENO);
+
+ MixRampAnalyzer a;
+
+ while (true) {
+ std::array<ReplayGainAnalyzer::Frame, 4096> buffer;
+
+ size_t nbytes = ReadFrames(input_fd,
+ buffer.data(), sizeof(buffer),
+ frame_size);
+ if (nbytes == 0)
+ break;
+
+ const std::size_t n_frames = nbytes / frame_size;
+ a.Process({buffer.data(), n_frames});
+ }
+
+ const auto data = a.GetResult();
+
+ const auto total_time = a.GetTime();
+
+ printf("MIXRAMP_START=");
+
+ MixRampItem last{};
+
+ for (const auto &i : data.start) {
+ if (i.time >= FloatDuration{} && i != last) {
+ printf("%.2f %.2f;", i.volume, i.time.count());
+ last = i;
+ }
+ }
+
+ printf("\n");
+
+ printf("MIXRAMP_END=");
+ last = {};
+ for (const auto &i : data.end) {
+ if (i.time >= FloatDuration{} && i != last) {
+ printf("%.2f %.2f;", i.volume, (total_time - i.time).count());
+ last = i;
+ }
+ }
+ printf("\n");
+
+ return EXIT_SUCCESS;
+} catch (...) {
+ PrintException(std::current_exception());
+ return EXIT_FAILURE;
+}
diff --git a/test/meson.build b/test/meson.build
index 01bcfd0ba..1701396df 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -567,6 +567,17 @@ executable(
],
)
+executable(
+ 'RunMixRampAnalyzer',
+ 'RunMixRampAnalyzer.cxx',
+ 'ReadFrames.cxx',
+ include_directories: inc,
+ dependencies: [
+ pcm_dep,
+ io_dep,
+ ],
+)
+
#
# Encoder
#