feat: load the user's mpv.conf

autotests/CMakeLists.txt

@@ -1,4 +1,9 @@
 ecm_add_test(subtitleparsertest.cpp
     TEST_NAME subtitleparsertest
-    LINK_LIBRARIES qtpotato_subtitles Qt6::Test
+    LINK_LIBRARIES qtpotato_core Qt6::Test
+)
+
+ecm_add_test(mpvuserconfigtest.cpp
+    TEST_NAME mpvuserconfigtest
+    LINK_LIBRARIES qtpotato_core Qt6::Test
 )

autotests/mpvuserconfigtest.cpp

@@ -0,0 +1,39 @@
+#include "mpvuserconfig.h"
+
+#include <QTest>
+
+using namespace Qt::Literals::StringLiterals;
+
+class MpvUserConfigTest : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void expandsConfigDirPaths()
+    {
+        const auto prepared = MpvUserConfig::prepare(u"glsl-shaders=\"~~/shaders/a.glsl\"\ninclude=~~home/extra.conf\n"_s, u"/home/me/.config/mpv"_s);
+        QCOMPARE(prepared.content, u"glsl-shaders=\"/home/me/.config/mpv/shaders/a.glsl\"\ninclude=/home/me/.config/mpv/extra.conf\n"_s);
+        QVERIFY(prepared.skippedOptions.isEmpty());
+    }
+
+    void skipsOptionsThatBreakEmbedding()
+    {
+        const QString conf = u"# comment\nvo=gpu-next\nhwdec=auto\n[big]\nno-fs\n--idle=no\n  vo = gpu\nvolume=50\n"_s;
+        const auto prepared = MpvUserConfig::prepare(conf, u"/c"_s);
+        QCOMPARE(prepared.skippedOptions, (QStringList{u"vo"_s, u"fs"_s, u"idle"_s}));
+        QCOMPARE(prepared.content,
+                 u"# comment\n# skipped by QtPotato: vo=gpu-next\nhwdec=auto\n[big]\n# skipped by QtPotato: no-fs\n"
+                 "# skipped by QtPotato: --idle=no\n# skipped by QtPotato:   vo = gpu\nvolume=50\n"_s);
+    }
+
+    void keepsSimilarlyNamedOptions()
+    {
+        // "vo" must not catch "volume" or "vo-..." style options.
+        const auto prepared = MpvUserConfig::prepare(u"volume=70\nvideo-sync=display-resample\nfs-screen=1\n"_s, u"/c"_s);
+        QVERIFY(prepared.skippedOptions.isEmpty());
+    }
+};
+
+QTEST_GUILESS_MAIN(MpvUserConfigTest)
+
+#include "mpvuserconfigtest.moc"

src/CMakeLists.txt

@@ -1,12 +1,15 @@
-# Subtitle parsing and extraction, kept apart from the app so autotests can link it.
-add_library(qtpotato_subtitles STATIC
+# Code without UI (subtitles, mpv.conf handling), kept apart from the app so autotests
+# can link it.
+add_library(qtpotato_core STATIC
+    mpv/mpvuserconfig.cpp
+    mpv/mpvuserconfig.h
     subtitles/subtitleparser.cpp
     subtitles/subtitleparser.h
     subtitles/subtitleextractor.cpp
     subtitles/subtitleextractor.h
 )
-target_include_directories(qtpotato_subtitles PUBLIC subtitles)
-target_link_libraries(qtpotato_subtitles PUBLIC
+target_include_directories(qtpotato_core PUBLIC mpv subtitles)
+target_link_libraries(qtpotato_core PUBLIC
     Qt6::Core
     KF6::I18n
     PRIVATE
@@ -52,7 +55,7 @@ target_include_directories(qtpotato PRIVATE mpv translate)
 target_compile_definitions(qtpotato PRIVATE QTPOTATO_VERSION_STRING="${PROJECT_VERSION}")
 
 target_link_libraries(qtpotato PRIVATE
-    qtpotato_subtitles
+    qtpotato_core
     Qt6::Gui
     Qt6::Qml
     Qt6::Quick

src/mpv/mpvitem.cpp

@@ -1,7 +1,14 @@
 #include "mpvitem.h"
 
+#include "mpvuserconfig.h"
+
 #include <MpvController>
 
+#include <QDir>
+#include <QFile>
+#include <QSaveFile>
+#include <QStandardPaths>
+
 #include <cmath>
 #include <utility>
 
@@ -58,6 +65,8 @@ MpvItem::MpvItem(QQuickItem *parent)
     // time; a file loaded before that plays without video. Hold it until ready() fires.
     connect(this, &MpvAbstractItem::ready, this, [this] {
         m_ready = true;
+        // Before the first file, so its options apply from the start.
+        applyUserConfig();
         if (m_pendingUrl.isValid()) {
             loadFile(std::exchange(m_pendingUrl, {}));
         }
@@ -208,6 +217,65 @@ void MpvItem::showText(const QString &text)
     commandAsync(QStringList{QStringLiteral("show-text"), text});
 }
 
+bool MpvItem::loadUserConfig() const
+{
+    return m_loadUserConfig;
+}
+
+void MpvItem::setLoadUserConfig(bool load)
+{
+    if (load != m_loadUserConfig) {
+        m_loadUserConfig = load;
+        Q_EMIT loadUserConfigChanged();
+    }
+}
+
+QString MpvItem::userConfigDir() const
+{
+    return MpvUserConfig::configDir();
+}
+
+QStringList MpvItem::loadedUserConfigFiles() const
+{
+    return m_loadedUserConfigFiles;
+}
+
+QStringList MpvItem::skippedUserOptions() const
+{
+    return m_skippedUserOptions;
+}
+
+void MpvItem::applyUserConfig()
+{
+    if (m_loadUserConfig) {
+        const QString cacheDir = QStandardPaths::writableLocation(QStandardPaths::CacheLocation) + QStringLiteral("/mpv");
+        QDir().mkpath(cacheDir);
+
+        const QStringList files = MpvUserConfig::configFiles();
+        for (qsizetype i = 0; i < files.size(); ++i) {
+            QFile source(files.at(i));
+            if (!source.open(QIODevice::ReadOnly)) {
+                continue;
+            }
+            const MpvUserConfig::Prepared prepared = MpvUserConfig::prepare(QString::fromUtf8(source.readAll()), MpvUserConfig::configDir());
+
+            // mpv only loads config from files, so the adapted copy goes to the cache.
+            QSaveFile copy(QStringLiteral("%1/mpv-%2.conf").arg(cacheDir).arg(i));
+            if (!copy.open(QIODevice::WriteOnly) || copy.write(prepared.content.toUtf8()) < 0 || !copy.commit()) {
+                continue;
+            }
+            commandAsync(QStringList{QStringLiteral("load-config-file"), copy.fileName()});
+            m_loadedUserConfigFiles.append(files.at(i));
+            for (const QString &option : prepared.skippedOptions) {
+                if (!m_skippedUserOptions.contains(option)) {
+                    m_skippedUserOptions.append(option);
+                }
+            }
+        }
+    }
+    Q_EMIT userConfigApplied();
+}
+
 void MpvItem::onPropertyChanged(const QString &property, const QVariant &value)
 {
     if (property == u"media-title") {

src/mpv/mpvitem.h

@@ -29,6 +29,13 @@ class MpvItem : public MpvAbstractItem
     // In seconds; applied to both subtitles so a translation stays in sync with its source.
     Q_PROPERTY(double subtitleDelay READ subtitleDelay WRITE setSubtitleDelay NOTIFY subtitleDelayChanged)
 
+    // Load the user's mpv.conf when mpv starts. Must be set before the item is shown.
+    Q_PROPERTY(bool loadUserConfig READ loadUserConfig WRITE setLoadUserConfig NOTIFY loadUserConfigChanged)
+    Q_PROPERTY(QString userConfigDir READ userConfigDir CONSTANT)
+    // The mpv.conf files that were loaded, and the options in them that were ignored.
+    Q_PROPERTY(QStringList loadedUserConfigFiles READ loadedUserConfigFiles NOTIFY userConfigApplied)
+    Q_PROPERTY(QStringList skippedUserOptions READ skippedUserOptions NOTIFY userConfigApplied)
+
 public:
     explicit MpvItem(QQuickItem *parent = nullptr);
     ~MpvItem() override = default;
@@ -48,6 +55,11 @@ public:
     void setSecondarySubtitleId(int id);
     double subtitleDelay() const;
     void setSubtitleDelay(double seconds);
+    bool loadUserConfig() const;
+    void setLoadUserConfig(bool load);
+    QString userConfigDir() const;
+    QStringList loadedUserConfigFiles() const;
+    QStringList skippedUserOptions() const;
 
     Q_INVOKABLE void loadFile(const QUrl &url);
     Q_INVOKABLE void togglePause();
@@ -69,11 +81,15 @@ Q_SIGNALS:
     void fileLoadedChanged();
     void subtitleTracksChanged();
     void subtitleDelayChanged();
+    void loadUserConfigChanged();
+    // mpv.conf was queued for loading; options set after this take precedence over it.
+    void userConfigApplied();
 
 private:
     void onPropertyChanged(const QString &property, const QVariant &value);
     void setFileLoaded(bool loaded);
     void updateTracks(const QVariantList &trackList);
+    void applyUserConfig();
 
     bool m_ready = false;
     QUrl m_pendingUrl;
@@ -89,4 +105,7 @@ private:
     double m_subtitleDelay = 0.0;
     // File added by showSecondarySubtitleFile() that should become secondary once mpv lists it.
     QString m_pendingSecondaryPath;
+    bool m_loadUserConfig = false;
+    QStringList m_loadedUserConfigFiles;
+    QStringList m_skippedUserOptions;
 };

src/mpv/mpvuserconfig.cpp

@@ -0,0 +1,95 @@
+#include "mpvuserconfig.h"
+
+#include <QDir>
+#include <QFileInfo>
+#include <QStandardPaths>
+
+using namespace Qt::Literals::StringLiterals;
+
+namespace
+{
+// vo must stay libmpv to render inside the window; idle=no would shut mpv down after
+// a file ends; the rest belong to a standalone mpv window.
+const QStringList SkippedOptions{
+    u"vo"_s,
+    u"idle"_s,
+    u"wid"_s,
+    u"fs"_s,
+    u"fullscreen"_s,
+    u"force-window"_s,
+    u"gpu-api"_s,
+    u"gpu-context"_s,
+    u"config"_s,
+    u"config-dir"_s,
+    u"player-operation-mode"_s,
+};
+
+// "--no-fs=yes" -> "fs"
+QString optionName(QStringView line)
+{
+    QStringView name = line;
+    if (name.startsWith(u"--")) {
+        name = name.mid(2);
+    }
+    const qsizetype end = name.indexOf(u'=');
+    if (end >= 0) {
+        name = name.left(end);
+    }
+    name = name.trimmed();
+    if (name.startsWith(u"no-")) {
+        name = name.mid(3);
+    }
+    return name.toString();
+}
+}
+
+namespace MpvUserConfig
+{
+QString configDir()
+{
+    if (const QString home = qEnvironmentVariable("MPV_HOME"); !home.isEmpty()) {
+        return QDir::cleanPath(home);
+    }
+    return QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + u"/mpv"_s;
+}
+
+QStringList configFiles()
+{
+    QStringList files;
+    for (const QString &path : QStringList{u"/etc/mpv/mpv.conf"_s, configDir() + u"/mpv.conf"_s}) {
+        if (QFileInfo(path).isFile()) {
+            files.append(path);
+        }
+    }
+    return files;
+}
+
+Prepared prepare(const QString &content, const QString &configDir)
+{
+    Prepared result;
+    QStringList lines;
+    const QString dir = configDir.endsWith(u'/') ? configDir : configDir + u'/';
+
+    for (QString line : QString(content).remove(u'\r').split(u'\n')) {
+        const QString trimmed = line.trimmed();
+        if (trimmed.isEmpty() || trimmed.startsWith(u'#') || trimmed.startsWith(u'[')) {
+            lines.append(line);
+            continue;
+        }
+
+        const QString name = optionName(trimmed);
+        if (SkippedOptions.contains(name)) {
+            if (!result.skippedOptions.contains(name)) {
+                result.skippedOptions.append(name);
+            }
+            lines.append(u"# skipped by QtPotato: "_s + line);
+            continue;
+        }
+
+        line.replace(u"~~home/"_s, dir).replace(u"~~/"_s, dir);
+        lines.append(line);
+    }
+    result.content = lines.join(u'\n');
+    return result;
+}
+}

src/mpv/mpvuserconfig.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <QStringList>
+
+// The user's mpv.conf, adapted for libmpv. MpvQt initializes mpv with config loading
+// off, so the files are loaded afterwards with "load-config-file". In that mode mpv
+// can't resolve "~~/" paths, and a few options would break the embedded player.
+namespace MpvUserConfig
+{
+// $MPV_HOME, else $XDG_CONFIG_HOME/mpv, else ~/.config/mpv.
+QString configDir();
+
+// Existing mpv.conf files in the order mpv reads them: system-wide, then the user's.
+QStringList configFiles();
+
+struct Prepared {
+    QString content;
+    // Option names that were dropped, in file order without duplicates.
+    QStringList skippedOptions;
+};
+
+// Expands "~~/" and "~~home/" to \a configDir and drops options that would take the
+// video out of the window or stop the player.
+Prepared prepare(const QString &content, const QString &configDir);
+}

src/qml/Main.qml

@@ -33,6 +33,7 @@ Kirigami.ApplicationWindow {
         id: settingsPage
         SettingsPage {
             translator: player.translator
+            mpvItem: player.mpvItem
         }
     }
 

src/qml/PlayerPage.qml

@@ -14,6 +14,7 @@ Kirigami.Page {
     property bool fullScreen: false
     readonly property alias mediaTitle: mpv.mediaTitle
     readonly property alias translator: translator
+    readonly property MpvItem mpvItem: mpv
 
     signal aboutRequested()
     signal settingsRequested()
@@ -175,6 +176,9 @@ Kirigami.Page {
 
         MpvItem {
             id: mpv
+            loadUserConfig: QtPotatoSettings.loadMpvConfig
+            // QtPotato's own subtitle settings win over mpv.conf.
+            onUserConfigApplied: page.applySubtitleStyle()
             anchors {
                 left: parent.left
                 right: parent.right

src/qml/SettingsPage.qml

@@ -9,6 +9,7 @@ FormCard.FormCardPage {
     id: page
 
     required property TranslationService translator
+    required property MpvItem mpvItem
 
     title: KI18n.i18nc("@title", "Settings")
 
@@ -27,6 +28,32 @@ FormCard.FormCardPage {
         onVisibleChanged: if (!visible) page.translator.clearError()
     }
 
+    FormCard.FormHeader {
+        title: KI18n.i18nc("@title:group", "Player")
+    }
+
+    FormCard.FormCard {
+        FormCard.FormSwitchDelegate {
+            text: KI18n.i18nc("@option:check", "Use mpv.conf")
+            description: KI18n.i18nc("@info", "Reads mpv.conf from %1, like the mpv player does. Changes apply the next time QtPotato starts. Subtitle text size and outline set below take precedence.", page.mpvItem.userConfigDir)
+            checked: QtPotatoSettings.loadMpvConfig
+            onToggled: QtPotatoSettings.loadMpvConfig = checked
+        }
+
+        FormCard.FormDelegateSeparator {}
+
+        FormCard.FormTextDelegate {
+            text: page.mpvItem.loadedUserConfigFiles.length > 0
+                ? KI18n.i18nc("@info", "Loaded: %1", page.mpvItem.loadedUserConfigFiles.join(", "))
+                : (QtPotatoSettings.loadMpvConfig
+                    ? KI18n.i18nc("@info", "No mpv.conf found")
+                    : KI18n.i18nc("@info", "mpv.conf is not used"))
+            description: page.mpvItem.skippedUserOptions.length > 0
+                ? KI18n.i18nc("@info", "Ignored because they would break the built-in player: %1", page.mpvItem.skippedUserOptions.join(", "))
+                : ""
+        }
+    }
+
     FormCard.FormHeader {
         title: KI18n.i18nc("@title:group", "Subtitles")
     }

src/settings/qtpotatosettings.kcfg

@@ -3,6 +3,12 @@
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.kde.org/standards/kcfg/1.0 http://www.kde.org/standards/kcfg/1.0/kcfg.xsd">
   <kcfgfile name="qtpotatorc"/>
+  <group name="Player">
+    <entry name="LoadMpvConfig" type="Bool">
+      <label>Load the user's mpv.conf when the player starts</label>
+      <default>true</default>
+    </entry>
+  </group>
   <group name="Subtitles">
     <entry name="SubtitleFontSize" type="Int">
       <label>Font size of plain-text and translated subtitles, in mpv's scaled pixels (mpv's own default is 38)</label>