diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a7bdb3e32..0e4400f30 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -136,6 +136,7 @@ jobs:
         with:
           name: ${{ matrix.config.name }} - installer
           path: build/Aegisub-*.exe
+          if-no-files-found: error
       
       - name: Upload artifacts - portable.zip
         uses: actions/upload-artifact@v3
@@ -157,3 +158,4 @@ jobs:
         with:
           name: ${{ matrix.config.name }} - installer
           path: build/Aegisub-*.dmg
+          if-no-files-found: error
diff --git a/automation/vapoursynth/aegisub_vs.py b/automation/vapoursynth/aegisub_vs.py
index c3cc5876c..1eca5f5d3 100644
--- a/automation/vapoursynth/aegisub_vs.py
+++ b/automation/vapoursynth/aegisub_vs.py
@@ -1,14 +1,14 @@
 """
-Utility functions for loading video files into Aegisub using the Vapoursynth
+Utility functions for loading video files into Aegisub using the VapourSynth
 video provider.
 
 When encountering a file whose file extension is not .py or .vpy, the
-Vapoursynth audio and video providers will execute the respective default
+VapourSynth audio and video providers will execute the respective default
 script set in Aegisub's configuration, with the following string variables set:
 - filename: The path to the file that's being opened.
 - __aegi_data, __aegi_dictionary, __aegi_local, __aegi_script, __aegi_temp, __aegi_user:
   The values of ?data, ?dictionary, etc. respectively.
-- __aegi_vscache: The path to a directory where the Vapoursynth script can
+- __aegi_vscache: The path to a directory where the VapourSynth script can
   store cache files. This directory is cleaned by Aegisub when it gets too
   large (as defined by Aegisub's configuration).
 
@@ -34,6 +34,43 @@ from typing import Any, Dict, List, Tuple
 import vapoursynth as vs
 core = vs.core
 
+aegi_vscache: str = ""
+aegi_vsplugins: str = ""
+
+plugin_extension = ".dll" if os.name == "nt" else ".so"
+
+def set_paths(vars: dict):
+    """
+    Initialize the wrapper library with the given configuration directories.
+    Should usually be called at the start of the default script as
+        set_paths(globals())
+    """
+    global aegi_vscache
+    global aegi_vsplugins
+    aegi_vscache = vars["__aegi_vscache"]
+    aegi_vsplugins = vars["__aegi_vsplugins"]
+
+
+def ensure_plugin(name: str, loadname: str, errormsg: str):
+    """
+    Ensures that the VapourSynth plugin with the given name exists.
+    If it doesn't, it tries to load it from `loadname`.
+    If that fails, it raises an error with the given error message.
+    """
+    if hasattr(core, name):
+        return
+
+    if aegi_vsplugins and loadname:
+        try:
+            core.std.LoadPlugin(os.path.join(aegi_vsplugins, loadname + plugin_extension))
+            if hasattr(core, name):
+                return
+        except vs.Error:
+            pass
+
+    raise vs.Error(errormsg)
+
+
 def make_lwi_cache_filename(filename: str) -> str:
     """
     Given a path to a video, will return a file name like the one LWLibavSource
@@ -103,21 +140,23 @@ def info_from_lwindex(indexfile: str) -> Dict[str, List[int]]:
     }
 
 
-def wrap_lwlibavsource(filename: str, cachedir: str, **kwargs: Any) -> Tuple[vs.VideoNode, Dict[str, List[int]]]:
+def wrap_lwlibavsource(filename: str, cachedir: str | None = None, **kwargs: Any) -> Tuple[vs.VideoNode, Dict[str, List[int]]]:
     """
     Given a path to a video file and a directory to store index files in
     (usually __aegi_vscache), will open the video with LWLibavSource and read
     the generated .lwi file to obtain the timecodes and keyframes.
     Additional keyword arguments are passed on to LWLibavSource.
     """
+    if cachedir is None:
+        cachedir = aegi_vscache
+
     try:
         os.mkdir(cachedir)
     except FileExistsError:
         pass
     cachefile = os.path.join(cachedir, make_lwi_cache_filename(filename))
 
-    if not hasattr(core, "lsmas"):
-        raise vs.Error("To use Aegisub's LWLibavSource wrapper, the `lsmas` plugin for VapourSynth must be installed")
+    ensure_plugin("lsmas", "libvslsmashsource", "To use Aegisub's LWLibavSource wrapper, the `lsmas` plugin for VapourSynth must be installed")
 
     if b"-Dcachedir" not in core.lsmas.Version()["config"]: # type: ignore
         raise vs.Error("To use Aegisub's LWLibavSource wrapper, the `lsmas` plugin must support the `cachedir` option for LWLibavSource.")
@@ -128,7 +167,7 @@ def wrap_lwlibavsource(filename: str, cachedir: str, **kwargs: Any) -> Tuple[vs.
 
 
 def make_keyframes(clip: vs.VideoNode, use_scxvid: bool = False,
-                   resize_h: int = 360, resize_format: int = vs.YUV420P8,
+                   resize_h: int = 360, resize_format: int = vs.GRAY8,
                    **kwargs: Any) -> List[int]:
     """
     Generates a list of keyframes from a clip, using either WWXD or Scxvid.
@@ -142,12 +181,14 @@ def make_keyframes(clip: vs.VideoNode, use_scxvid: bool = False,
     The remaining keyword arguments are passed on to the respective filter.
     """
 
-    clip = core.resize.Bilinear(clip, width=resize_h * clip.width // clip.height, height=resize_h, format=resize_format);
-    try:
-        clip = core.scxvid.Scxvid(clip, **kwargs) if use_scxvid else core.wwxd.WWXD(clip, **kwargs)
-    except AttributeError:
-        raise vs.Error("To use the keyframe generation, the `{}` plugin for VapourSynth must be installed"
-                       .format("scxvid" if use_scxvid else "wwxd"))
+    clip = core.resize.Bilinear(clip, width=resize_h * clip.width // clip.height, height=resize_h, format=resize_format)
+
+    if use_scxvid:
+        ensure_plugin("scxvid", "libscxvid", "To use the keyframe generation, the scxvid plugin for VapourSynth must be installed")
+        clip = core.scxvid.Scxvid(clip, **kwargs)
+    else:
+        ensure_plugin("wwxd", "libwwxd64", "To use the keyframe generation, the wwxdplugin for VapourSynth must be installed")
+        clip = core.wwxd.WWXD(clip, **kwargs)
 
     keyframes = {}
     done = 0
@@ -175,6 +216,16 @@ def save_keyframes(filename: str, keyframes: List[int]):
         f.write("".join(f"{n}\n" for n in keyframes))
 
 
+def try_get_keyframes(filename: str, default: str | List[int]) -> str | List[int]:
+    """
+    Checks if a keyframes file for the given filename is present and, if so,
+    returns it. Otherwise, returns the given list of keyframes.
+    """
+    kffilename = make_keyframes_filename(filename)
+
+    return kffilename if os.path.exists(kffilename) else default
+
+
 def get_keyframes(filename: str, clip: vs.VideoNode, **kwargs: Any) -> str:
     """
     When not already present, creates a keyframe file for the given clip next
@@ -199,6 +250,7 @@ def check_audio(filename: str, **kwargs: Any) -> bool:
     Additional keyword arguments are passed on to BestAudioSource.
     """
     try:
+        ensure_plugin("bas", "BestAudioSource", "")
         vs.core.bas.Source(source=filename, **kwargs)
         return True
     except AttributeError:
diff --git a/packages/win_installer/fragment_codecs.iss b/packages/win_installer/fragment_codecs.iss
index 06e73b037..f71f74b31 100644
--- a/packages/win_installer/fragment_codecs.iss
+++ b/packages/win_installer/fragment_codecs.iss
@@ -5,3 +5,8 @@ DestDir: {app}; Source: {#DEPS_DIR}\AvisynthPlus64\x64\AviSynth.dll; Flags: igno
 DestDir: {app}; Source: {#DEPS_DIR}\AvisynthPlus64\x64\plugins\DirectShowSource.dll; Flags: ignoreversion; Components: main
 ; VSFilter
 DestDir: {app}\csri; Source: {#DEPS_DIR}\VSFilter\x64\VSFilter.dll; Flags: ignoreversion; Components: main
+; VapourSynth
+DestDir: {app}\vapoursynth; Source: {#DEPS_DIR}\L-SMASH-Works\libvslsmashsource.dll; Flags: ignoreversion; Components: vapoursynth
+DestDir: {app}\vapoursynth; Source: {#DEPS_DIR}\bestaudiosource\win64\BestAudioSource.dll; Flags: ignoreversion; Components: vapoursynth
+DestDir: {app}\vapoursynth; Source: {#DEPS_DIR}\SCXVid\libscxvid.dll; Flags: ignoreversion; Components: vapoursynth
+DestDir: {app}\vapoursynth; Source: {#DEPS_DIR}\WWXD\libwwxd64.dll; Flags: ignoreversion; Components: vapoursynth
diff --git a/packages/win_installer/fragment_mainprogram.iss b/packages/win_installer/fragment_mainprogram.iss
index 7feeaf740..4337261b7 100644
--- a/packages/win_installer/fragment_mainprogram.iss
+++ b/packages/win_installer/fragment_mainprogram.iss
@@ -1,5 +1,6 @@
 [Components]
 Name: "main"; Description: "Main Files"; Types: full compact custom; Flags: fixed
+Name: "vapoursynth"; Description: "Bundled VapourSynth Plugins"; Types: full
 Name: "macros"; Description: "Automation Scripts"; Types: full
 Name: "macros\bundled"; Description: "Bundled macros"; Types: full
 Name: "macros\demos"; Description: "Example macros/Demos"; Types: full
diff --git a/packages/win_installer/fragment_spelling.iss b/packages/win_installer/fragment_spelling.iss
index 331f3eb29..8e4168727 100644
--- a/packages/win_installer/fragment_spelling.iss
+++ b/packages/win_installer/fragment_spelling.iss
@@ -1,5 +1,5 @@
 ; This file declares all installables related to spell checking and thesaurii in Aegisub
 
 [Files]
-Source: {#DEPS_DIR}\dictionaries\en_US.aff; DestDir: {app}\dictionaries; Flags: skipifsourcedoesntexist ignoreversion
-Source: {#DEPS_DIR}\dictionaries\en_US.dic; DestDir: {app}\dictionaries; Flags: skipifsourcedoesntexist ignoreversion
+Source: {#DEPS_DIR}\dictionaries\en_US.aff; DestDir: {app}\dictionaries; Flags: ignoreversion; Components: dictionaries/en_US
+Source: {#DEPS_DIR}\dictionaries\en_US.dic; DestDir: {app}\dictionaries; Flags: ignoreversion; Components: dictionaries/en_US
diff --git a/packages/win_installer/portable/create-portable.ps1 b/packages/win_installer/portable/create-portable.ps1
index 4f4717bfe..22dc88b15 100644
--- a/packages/win_installer/portable/create-portable.ps1
+++ b/packages/win_installer/portable/create-portable.ps1
@@ -51,11 +51,19 @@ Copy-New-Item $InstallerDir\bin\aegisub.exe  $PortableOutputDir
 
 Write-Output 'Copying - translations'
 Copy-New-Items "$InstallerDir\share\locale\*"  "$PortableOutputDir\locale" -Recurse
+Write-Output 'Copying - dictionaries'
+Copy-New-Item $InstallerDepsDir\dictionaries\en_US.aff  $PortableOutputDir\dictionaries
+Copy-New-Item $InstallerDepsDir\dictionaries\en_US.dic  $PortableOutputDir\dictionaries
 Write-Output 'Copying - codecs'
 Write-Output 'Copying - codecs\Avisynth'
 Copy-New-Item $InstallerDepsDir\AvisynthPlus64\x64\system\DevIL.dll  $PortableOutputDir
 Copy-New-Item $InstallerDepsDir\AvisynthPlus64\x64\AviSynth.dll  $PortableOutputDir
 Copy-New-Item $InstallerDepsDir\AvisynthPlus64\x64\plugins\DirectShowSource.dll  $PortableOutputDir
+Write-Output 'Copying - codecs\VapourSynth'
+Copy-New-Item $InstallerDepsDir\L-SMASH-Works\libvslsmashsource.dll  $PortableOutputDir\vapoursynth
+Copy-New-Item $InstallerDepsDir\bestaudiosource\win64\BestAudioSource.dll  $PortableOutputDir\vapoursynth
+Copy-New-Item $InstallerDepsDir\SCXVid\libscxvid.dll  $PortableOutputDir\vapoursynth
+Copy-New-Item $InstallerDepsDir\WWXD\libwwxd64.dll  $PortableOutputDir\vapoursynth
 Write-Output 'Copying - codecs\VSFilter'
 Copy-New-Item $InstallerDepsDir\VSFilter\x64\VSFilter.dll  $PortableOutputDir\csri
 Write-Output 'Copying - runtimes\MS-CRT'
diff --git a/src/audio_provider_factory.cpp b/src/audio_provider_factory.cpp
index 71c34f66e..d2597cee4 100644
--- a/src/audio_provider_factory.cpp
+++ b/src/audio_provider_factory.cpp
@@ -32,7 +32,7 @@ using namespace agi;
 std::unique_ptr<AudioProvider> CreateAvisynthAudioProvider(fs::path const& filename, BackgroundRunner *);
 std::unique_ptr<AudioProvider> CreateFFmpegSourceAudioProvider(fs::path const& filename, BackgroundRunner *);
 std::unique_ptr<AudioProvider> CreateBSAudioProvider(fs::path const& filename, BackgroundRunner *);
-std::unique_ptr<AudioProvider> CreateVapoursynthAudioProvider(fs::path const& filename, BackgroundRunner *);
+std::unique_ptr<AudioProvider> CreateVapourSynthAudioProvider(fs::path const& filename, BackgroundRunner *);
 
 namespace {
 struct factory {
@@ -54,7 +54,7 @@ const factory providers[] = {
 	{"BestSource", CreateBSAudioProvider, false},
 #endif
 #ifdef WITH_VAPOURSYNTH
-	{"Vapoursynth", CreateVapoursynthAudioProvider, false},
+	{"VapourSynth", CreateVapourSynthAudioProvider, false},
 #endif
 };
 }
diff --git a/src/audio_provider_vs.cpp b/src/audio_provider_vs.cpp
index 1f42803be..2d81f06bb 100644
--- a/src/audio_provider_vs.cpp
+++ b/src/audio_provider_vs.cpp
@@ -15,7 +15,7 @@
 // Aegisub Project http://www.aegisub.org/
 
 /// @file audio_provider_vs.cpp
-/// @brief Vapoursynth-based audio provider
+/// @brief VapourSynth-based audio provider
 /// @ingroup audio_input
 ///
 
@@ -38,7 +38,7 @@
 #include "VSScript4.h"
 
 namespace {
-class VapoursynthAudioProvider final : public agi::AudioProvider {
+class VapourSynthAudioProvider final : public agi::AudioProvider {
 	VapourSynthWrapper vs;
 	VSScript *script = nullptr;
 	VSNode *node = nullptr;
@@ -47,36 +47,36 @@ class VapoursynthAudioProvider final : public agi::AudioProvider {
 	void FillBufferWithFrame(void *buf, int frame, int64_t start, int64_t count) const;
 	void FillBuffer(void *buf, int64_t start, int64_t count) const override;
 public:
-	VapoursynthAudioProvider(agi::fs::path const& filename);
-	~VapoursynthAudioProvider();
+	VapourSynthAudioProvider(agi::fs::path const& filename);
+	~VapourSynthAudioProvider();
 
 	bool NeedsCache() const override { return true; }
 };
 
-VapoursynthAudioProvider::VapoursynthAudioProvider(agi::fs::path const& filename) try {
+VapourSynthAudioProvider::VapourSynthAudioProvider(agi::fs::path const& filename) try {
 	std::lock_guard<std::mutex> lock(vs.GetMutex());
 
 	VSCleanCache();
 
 	script = vs.GetScriptAPI()->createScript(nullptr);
 	if (script == nullptr) {
-		throw VapoursynthError("Error creating script API");
+		throw VapourSynthError("Error creating script API");
 	}
 	vs.GetScriptAPI()->evalSetWorkingDir(script, 1);
 	if (OpenScriptOrVideo(vs.GetAPI(), vs.GetScriptAPI(), script, filename, OPT_GET("Provider/Audio/VapourSynth/Default Script")->GetString())) {
 		std::string msg = agi::format("Error executing VapourSynth script: %s", vs.GetScriptAPI()->getError(script));
 		vs.GetScriptAPI()->freeScript(script);
-		throw VapoursynthError(msg);
+		throw VapourSynthError(msg);
 	}
 	node = vs.GetScriptAPI()->getOutputNode(script, 0);
 	if (node == nullptr) {
 		vs.GetScriptAPI()->freeScript(script);
-		throw VapoursynthError("No output node set");
+		throw VapourSynthError("No output node set");
 	}
 	if (vs.GetAPI()->getNodeType(node) != mtAudio) {
 		vs.GetAPI()->freeNode(node);
 		vs.GetScriptAPI()->freeScript(script);
-		throw VapoursynthError("Output node isn't an audio node");
+		throw VapourSynthError("Output node isn't an audio node");
 	}
 	vi = vs.GetAPI()->getAudioInfo(node);
 	float_samples = vi->format.sampleType == stFloat;
@@ -85,10 +85,10 @@ VapoursynthAudioProvider::VapoursynthAudioProvider(agi::fs::path const& filename
 	channels = vi->format.numChannels;
 	num_samples = vi->numSamples;
 }
-catch (VapoursynthError const& err) {
+catch (VapourSynthError const& err) {
 	// Unlike the video provider manager, the audio provider factory catches AudioProviderErrors and picks whichever source doesn't throw one.
 	// So just rethrow the Error here with an extra label so the user will see the error message and know the audio wasn't loaded with VS
-	throw VapoursynthError(agi::format("Vapoursynth error: %s", err.GetMessage()));
+	throw VapourSynthError(agi::format("VapourSynth error: %s", err.GetMessage()));
 }
 
 template<typename T>
@@ -102,19 +102,19 @@ static void PackChannels(const uint8_t **Src, void *Dst, size_t Length, size_t C
 	}
 }
 
-void VapoursynthAudioProvider::FillBufferWithFrame(void *buf, int n, int64_t start, int64_t count) const {
+void VapourSynthAudioProvider::FillBufferWithFrame(void *buf, int n, int64_t start, int64_t count) const {
 	char errorMsg[1024];
 	const VSFrame *frame = vs.GetAPI()->getFrame(n, node, errorMsg, sizeof(errorMsg));
 	if (frame == nullptr) {
-		throw VapoursynthError(agi::format("Error getting frame: %s", errorMsg));
+		throw VapourSynthError(agi::format("Error getting frame: %s", errorMsg));
 	}
 	if (vs.GetAPI()->getFrameLength(frame) < count) {
 		vs.GetAPI()->freeFrame(frame);
-		throw VapoursynthError("Audio frame too short");
+		throw VapourSynthError("Audio frame too short");
 	}
 	if (vs.GetAPI()->getAudioFrameFormat(frame)->numChannels != channels || vs.GetAPI()->getAudioFrameFormat(frame)->bytesPerSample != bytes_per_sample) {
 		vs.GetAPI()->freeFrame(frame);
-		throw VapoursynthError("Audio format is not constant");
+		throw VapourSynthError("Audio format is not constant");
 	}
 
 	std::vector<const uint8_t *> planes(channels);
@@ -122,7 +122,7 @@ void VapoursynthAudioProvider::FillBufferWithFrame(void *buf, int n, int64_t sta
 		planes[c] = vs.GetAPI()->getReadPtr(frame, c) + bytes_per_sample * start;
 		if (planes[c] == nullptr) {
 			vs.GetAPI()->freeFrame(frame);
-			throw VapoursynthError("Failed to read audio channel");
+			throw VapourSynthError("Failed to read audio channel");
 		}
 	}
 
@@ -138,7 +138,7 @@ void VapoursynthAudioProvider::FillBufferWithFrame(void *buf, int n, int64_t sta
 	vs.GetAPI()->freeFrame(frame);
 }
 
-void VapoursynthAudioProvider::FillBuffer(void *buf, int64_t start, int64_t count) const {
+void VapourSynthAudioProvider::FillBuffer(void *buf, int64_t start, int64_t count) const {
 	int end = start + count; 	// exclusive
 	int startframe = start / VS_AUDIO_FRAME_SAMPLES;
 	int endframe = (end - 1) / VS_AUDIO_FRAME_SAMPLES;
@@ -154,7 +154,7 @@ void VapoursynthAudioProvider::FillBuffer(void *buf, int64_t start, int64_t coun
 	}
 }
 
-VapoursynthAudioProvider::~VapoursynthAudioProvider() {
+VapourSynthAudioProvider::~VapourSynthAudioProvider() {
 	if (node != nullptr) {
 		vs.GetAPI()->freeNode(node);
 	}
@@ -164,7 +164,7 @@ VapoursynthAudioProvider::~VapoursynthAudioProvider() {
 }
 }
 
-std::unique_ptr<agi::AudioProvider> CreateVapoursynthAudioProvider(agi::fs::path const& file, agi::BackgroundRunner *) {
-	return agi::make_unique<VapoursynthAudioProvider>(file);
+std::unique_ptr<agi::AudioProvider> CreateVapourSynthAudioProvider(agi::fs::path const& file, agi::BackgroundRunner *) {
+	return agi::make_unique<VapourSynthAudioProvider>(file);
 }
 #endif
diff --git a/src/libresrc/default_config.json b/src/libresrc/default_config.json
index e6c8d088d..c83002c31 100644
--- a/src/libresrc/default_config.json
+++ b/src/libresrc/default_config.json
@@ -351,7 +351,7 @@
 				"Aegisub Cache" : true
 			},
 			"VapourSynth" : {
-				"Default Script" : "# This default script will load an audio file using BestAudioSource.\n# It requires the `bas` plugin.\n\nimport vapoursynth as vs\ntry:\n    vs.core.bas.Source(source=filename).set_output()\nexcept AttributeError:\n   raise vs.Error(\"To use Aegisub's default audio loader, the `bas` plugin for VapourSynth must be installed\")"
+				"Default Script" : "# This default script will load an audio file using BestAudioSource.\n# It requires the `bas` plugin.\n\nimport vapoursynth as vs\nimport aegisub_vs as a\na.set_paths(locals())\n\na.ensure_plugin(\"bas\", \"BestAudioSource\", \"To use Aegisub's default audio loader, the `bas` plugin for VapourSynth must be installed\")\nvs.core.bas.Source(source=filename).set_output()"
 			}
 		},
 		"Avisynth" : {
@@ -392,7 +392,7 @@
 			},
 			"VapourSynth" : {
 				"Log Level": "Information",
-				"Default Script" : "# This default script will load a video file using LWLibavSource.\n# It requires the `lsmas` plugin.\n# See ?data/automation/vapoursynth/aegisub_vs.py for more information.\n\nimport aegisub_vs as a\nimport vapoursynth as vs\n\nclip, videoinfo = a.wrap_lwlibavsource(filename, __aegi_vscache)\nclip.set_output()\n__aegi_timecodes = videoinfo[\"timecodes\"]\n__aegi_keyframes = videoinfo[\"keyframes\"]\n# Uncomment this to automatically generate keyframes at scene changes.\n#__aegi_keyframes = a.get_keyframes(filename, clip)\n\n# Check if the file has an audio track. This requires the `bas` plugin.\n__aegi_hasaudio = 1 if a.check_audio(filename) else 0"
+				"Default Script" : "# This default script will load a video file using LWLibavSource.\n# It requires the `lsmas` plugin.\n# See ?data/automation/vapoursynth/aegisub_vs.py for more information.\n\nimport vapoursynth as vs\nimport time\nimport aegisub_vs as a\na.set_paths(locals())\n\nclip, videoinfo = a.wrap_lwlibavsource(filename)\nclip.set_output()\n__aegi_timecodes = videoinfo[\"timecodes\"]\n__aegi_keyframes = videoinfo[\"keyframes\"]\n\n# Uncomment the first following line to read keyframes from a file when present.\n#__aegi_keyframes = a.try_get_keyframes(filename, __aegi_keyframes)\n\n# Uncomment the following line to automatically generate keyframes at scene changes. This will take some time when first loading a video.\n__aegi_keyframes = a.get_keyframes(filename, clip)\n\n# Check if the file has an audio track. This requires the `bas` plugin.\n__aegi_hasaudio = 1 if a.check_audio(filename) else 0"
 			}
 		}
 	},
diff --git a/src/libresrc/osx/default_config.json b/src/libresrc/osx/default_config.json
index 38e58a404..8bb115f54 100644
--- a/src/libresrc/osx/default_config.json
+++ b/src/libresrc/osx/default_config.json
@@ -351,7 +351,7 @@
 				"Aegisub Cache" : true
 			},
 			"VapourSynth" : {
-				"Default Script" : "# This default script will load an audio file using BestAudioSource.\n# It requires the `bas` plugin.\n\nimport vapoursynth as vs\ntry:\n    vs.core.bas.Source(source=filename).set_output()\nexcept AttributeError:\n   raise vs.Error(\"To use Aegisub's default audio loader, the `bas` plugin for VapourSynth must be installed\")"
+				"Default Script" : "# This default script will load an audio file using BestAudioSource.\n# It requires the `bas` plugin.\n\nimport vapoursynth as vs\nimport aegisub_vs as a\na.set_paths(globals())\n\na.ensure_plugin(\"bas\", \"BestAudioSource\", \"To use Aegisub's default audio loader, the `bas` plugin for VapourSynth must be installed\")\nvs.core.bas.Source(source=filename).set_output()"
 			}
 		},
 		"Avisynth" : {
@@ -392,7 +392,7 @@
 			},
 			"VapourSynth" : {
 				"Log Level": "Information",
-				"Default Script" : "# This default script will load a video file using LWLibavSource.\n# It requires the `lsmas` plugin.\n# See ?data/automation/vapoursynth/aegisub_vs.py for more information.\n\nimport aegisub_vs as a\nimport vapoursynth as vs\n\nclip, videoinfo = a.wrap_lwlibavsource(filename, __aegi_vscache)\nclip.set_output()\n__aegi_timecodes = videoinfo[\"timecodes\"]\n__aegi_keyframes = videoinfo[\"keyframes\"]\n# Uncomment this to automatically generate keyframes at scene changes.\n#__aegi_keyframes = a.get_keyframes(filename, clip)\n\n# Check if the file has an audio track. This requires the `bas` plugin.\n__aegi_hasaudio = 1 if a.check_audio(filename) else 0"
+				"Default Script" : "# This default script will load a video file using LWLibavSource.\n# It requires the `lsmas` plugin.\n# See ?data/automation/vapoursynth/aegisub_vs.py for more information.\n\nimport vapoursynth as vs\nimport time\nimport aegisub_vs as a\na.set_paths(locals())\n\nclip, videoinfo = a.wrap_lwlibavsource(filename)\nclip.set_output()\n__aegi_timecodes = videoinfo[\"timecodes\"]\n__aegi_keyframes = videoinfo[\"keyframes\"]\n\n# Uncomment the first following line to read keyframes from a file when present.\n#__aegi_keyframes = a.try_get_keyframes(filename, __aegi_keyframes)\n\n# Uncomment the following line to automatically generate keyframes at scene changes. This will take some time when first loading a video.\n__aegi_keyframes = a.get_keyframes(filename, clip)\n\n# Check if the file has an audio track. This requires the `bas` plugin.\n__aegi_hasaudio = 1 if a.check_audio(filename) else 0"
 			}
 		}
 	},
diff --git a/src/vapoursynth_common.cpp b/src/vapoursynth_common.cpp
index b360c6144..e5346f6bc 100644
--- a/src/vapoursynth_common.cpp
+++ b/src/vapoursynth_common.cpp
@@ -28,7 +28,7 @@
 
 void SetStringVar(const VSAPI *api, VSMap *map, std::string variable, std::string value) {
 	if (api->mapSetData(map, variable.c_str(), value.c_str(), -1, dtUtf8, 1))
-		throw VapoursynthError("Failed to set VSMap entry");
+		throw VapourSynthError("Failed to set VSMap entry");
 }
 
 int OpenScriptOrVideo(const VSAPI *api, const VSSCRIPTAPI *sapi, VSScript *script, agi::fs::path const& filename, std::string default_script) {
@@ -38,16 +38,21 @@ int OpenScriptOrVideo(const VSAPI *api, const VSSCRIPTAPI *sapi, VSScript *scrip
 	} else {
 		VSMap *map = api->createMap();
 		if (map == nullptr)
-			throw VapoursynthError("Failed to create VSMap for script info");
+			throw VapourSynthError("Failed to create VSMap for script info");
 
 		SetStringVar(api, map, "filename", filename.string());
 		SetStringVar(api, map, "__aegi_vscache", config::path->Decode("?local/vscache").string());
+#ifdef WIN32
+		SetStringVar(api, map, "__aegi_vsplugins", config::path->Decode("?data/vapoursynth").string());
+#else
+		SetStringVar(api, map, "__aegi_vsplugins", "");
+#endif
 		for (std::string dir : { "data", "dictionary", "local", "script", "temp", "user", })
 			// Don't include ?audio and ?video in here since these only hold the paths to the previous audio/video files.
 			SetStringVar(api, map, "__aegi_" + dir, config::path->Decode("?" + dir).string());
 
 		if (sapi->setVariables(script, map))
-			throw VapoursynthError("Failed to set script info variables");
+			throw VapourSynthError("Failed to set script info variables");
 
 		api->freeMap(map);
 
diff --git a/src/vapoursynth_wrap.cpp b/src/vapoursynth_wrap.cpp
index 33c7de659..f9f64add9 100644
--- a/src/vapoursynth_wrap.cpp
+++ b/src/vapoursynth_wrap.cpp
@@ -15,7 +15,7 @@
 // Aegisub Project http://www.aegisub.org/
 
 /// @file vapoursynth_wrap.cpp
-/// @brief Wrapper-layer for Vapoursynth
+/// @brief Wrapper-layer for VapourSynth
 /// @ingroup video_input audio_input
 ///
 
@@ -67,7 +67,7 @@ VapourSynthWrapper::VapourSynthWrapper() {
 #endif
 
 		if (!hLib)
-			throw VapoursynthError("Could not load " VSSCRIPT_SO);
+			throw VapourSynthError("Could not load " VSSCRIPT_SO);
 
 #ifdef _WIN32
 		FUNC* getVSScriptAPI = (FUNC*)GetProcAddress(hLib, "getVSScriptAPI");
@@ -75,7 +75,7 @@ VapourSynthWrapper::VapourSynthWrapper() {
 		FUNC* getVSScriptAPI = (FUNC*)dlsym(hLib, "getVSScriptAPI");
 #endif
 		if (!getVSScriptAPI)
-			throw VapoursynthError("Failed to get address of getVSScriptAPI from " VSSCRIPT_SO);
+			throw VapourSynthError("Failed to get address of getVSScriptAPI from " VSSCRIPT_SO);
 
 		// Python will set the program's locale to the user's default locale, which will break
 		// half of wxwidgets on some operating systems due to locale mismatches. There's not really anything
@@ -85,12 +85,12 @@ VapourSynthWrapper::VapourSynthWrapper() {
 		setlocale(LC_ALL, oldlocale.c_str());
 
 		if (!scriptapi)
-			throw VapoursynthError("Failed to get Vapoursynth ScriptAPI");
+			throw VapourSynthError("Failed to get VapourSynth ScriptAPI");
 
 		api = scriptapi->getVSAPI(VAPOURSYNTH_API_VERSION);
 
 		if (!api)
-			throw VapoursynthError("Failed to get Vapoursynth API");
+			throw VapourSynthError("Failed to get VapourSynth API");
 
 		vs_loaded = true;
 	}
diff --git a/src/vapoursynth_wrap.h b/src/vapoursynth_wrap.h
index 802cb3d58..ee07235ff 100644
--- a/src/vapoursynth_wrap.h
+++ b/src/vapoursynth_wrap.h
@@ -23,7 +23,7 @@
 
 #include <libaegisub/exception.h>
 
-DEFINE_EXCEPTION(VapoursynthError, agi::Exception);
+DEFINE_EXCEPTION(VapourSynthError, agi::Exception);
 
 struct VSAPI;
 struct VSSCRIPTAPI;
diff --git a/src/video_provider_manager.cpp b/src/video_provider_manager.cpp
index a15df8b17..9374a7c84 100644
--- a/src/video_provider_manager.cpp
+++ b/src/video_provider_manager.cpp
@@ -30,7 +30,7 @@ std::unique_ptr<VideoProvider> CreateYUV4MPEGVideoProvider(agi::fs::path const&,
 std::unique_ptr<VideoProvider> CreateFFmpegSourceVideoProvider(agi::fs::path const&, std::string const&, agi::BackgroundRunner *);
 std::unique_ptr<VideoProvider> CreateAvisynthVideoProvider(agi::fs::path const&, std::string const&, agi::BackgroundRunner *);
 std::unique_ptr<VideoProvider> CreateBSVideoProvider(agi::fs::path const&, std::string const&, agi::BackgroundRunner *);
-std::unique_ptr<VideoProvider> CreateVapoursynthVideoProvider(agi::fs::path const&, std::string const&, agi::BackgroundRunner *);
+std::unique_ptr<VideoProvider> CreateVapourSynthVideoProvider(agi::fs::path const&, std::string const&, agi::BackgroundRunner *);
 
 std::unique_ptr<VideoProvider> CreateCacheVideoProvider(std::unique_ptr<VideoProvider>);
 
@@ -54,7 +54,7 @@ namespace {
 		{"BestSource (SLOW)", CreateBSVideoProvider, false},
 #endif
 #ifdef WITH_VAPOURSYNTH
-		{"Vapoursynth", CreateVapoursynthVideoProvider, false},
+		{"VapourSynth", CreateVapourSynthVideoProvider, false},
 #endif
 	};
 }
diff --git a/src/video_provider_vs.cpp b/src/video_provider_vs.cpp
index b08dd65a6..da4a3d1a5 100644
--- a/src/video_provider_vs.cpp
+++ b/src/video_provider_vs.cpp
@@ -42,7 +42,7 @@ static const char *tc_key = "__aegi_timecodes";
 static const char *audio_key = "__aegi_hasaudio";
 
 namespace {
-class VapoursynthVideoProvider: public VideoProvider {
+class VapourSynthVideoProvider: public VideoProvider {
 	VapourSynthWrapper vs;
 	VSScript *script = nullptr;
 	VSNode *node = nullptr;
@@ -59,8 +59,8 @@ class VapoursynthVideoProvider: public VideoProvider {
 	void SetResizeArg(VSMap *args, const VSMap *props, const char *arg_name, const char *prop_name, int64_t deflt, int64_t unspecified = -1);
 
 public:
-	VapoursynthVideoProvider(agi::fs::path const& filename, std::string const& colormatrix, agi::BackgroundRunner *br);
-	~VapoursynthVideoProvider();
+	VapourSynthVideoProvider(agi::fs::path const& filename, std::string const& colormatrix, agi::BackgroundRunner *br);
+	~VapourSynthVideoProvider();
 
 	void GetFrame(int n, VideoFrame &frame) override;
 
@@ -105,7 +105,7 @@ std::string colormatrix_description(int colorFamily, int colorRange, int matrix)
 }
 
 // Adds an argument to the rescaler if the corresponding frameprop does not exist or is set as unspecified
-void VapoursynthVideoProvider::SetResizeArg(VSMap *args, const VSMap *props, const char *arg_name, const char *prop_name, int64_t deflt, int64_t unspecified) {
+void VapourSynthVideoProvider::SetResizeArg(VSMap *args, const VSMap *props, const char *arg_name, const char *prop_name, int64_t deflt, int64_t unspecified) {
 	int err;
 	int64_t result = vs.GetAPI()->mapGetInt(props, prop_name, 0, &err);
 	if (err != 0 || result == unspecified) {
@@ -117,7 +117,7 @@ void VapoursynthVideoProvider::SetResizeArg(VSMap *args, const VSMap *props, con
 	}
 }
 
-VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename, std::string const& colormatrix, agi::BackgroundRunner *br) try { try {
+VapourSynthVideoProvider::VapourSynthVideoProvider(agi::fs::path const& filename, std::string const& colormatrix, agi::BackgroundRunner *br) try { try {
 	std::lock_guard<std::mutex> lock(vs.GetMutex());
 
 	VSCleanCache();
@@ -125,16 +125,16 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 	int err1, err2;
 	VSCore *core = vs.GetAPI()->createCore(0);
 	if (core == nullptr) {
-		throw VapoursynthError("Error creating core");
+		throw VapourSynthError("Error creating core");
 	}
 	script = vs.GetScriptAPI()->createScript(core);
 	if (script == nullptr) {
 		vs.GetAPI()->freeCore(core);
-		throw VapoursynthError("Error creating script API");
+		throw VapourSynthError("Error creating script API");
 	}
 	vs.GetScriptAPI()->evalSetWorkingDir(script, 1);
 	br->Run([&](agi::ProgressSink *ps) {
-		ps->SetTitle(from_wx(_("Executing Vapoursynth Script")));
+		ps->SetTitle(from_wx(_("Executing VapourSynth Script")));
 		ps->SetMessage("");
 		ps->SetIndeterminate();
 
@@ -148,20 +148,20 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 	});
 	if (err1) {
 		std::string msg = agi::format("Error executing VapourSynth script: %s", vs.GetScriptAPI()->getError(script));
-		throw VapoursynthError(msg);
+		throw VapourSynthError(msg);
 	}
 	node = vs.GetScriptAPI()->getOutputNode(script, 0);
 	if (node == nullptr)
-		throw VapoursynthError("No output node set");
+		throw VapourSynthError("No output node set");
 
 	if (vs.GetAPI()->getNodeType(node) != mtVideo) {
-		throw VapoursynthError("Output node isn't a video node");
+		throw VapourSynthError("Output node isn't a video node");
 	}
 	vi = vs.GetAPI()->getVideoInfo(node);
 	if (vi == nullptr)
-		throw VapoursynthError("Couldn't get video info");
+		throw VapourSynthError("Couldn't get video info");
 	if (!vsh::isConstantVideoFormat(vi))
-		throw VapoursynthError("Video doesn't have constant format");
+		throw VapourSynthError("Video doesn't have constant format");
 
 	int fpsNum = vi->fpsNum;
 	int fpsDen = vi->fpsDen;
@@ -174,7 +174,7 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 	// Get timecodes and/or keyframes if provided
 	VSMap *clipinfo = vs.GetAPI()->createMap();
 	if (clipinfo == nullptr)
-		throw VapoursynthError("Couldn't create map");
+		throw VapourSynthError("Couldn't create map");
 	vs.GetScriptAPI()->getVariable(script, kf_key, clipinfo);
 	vs.GetScriptAPI()->getVariable(script, tc_key, clipinfo);
 	vs.GetScriptAPI()->getVariable(script, audio_key, clipinfo);
@@ -190,7 +190,7 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		const int64_t *kfs = vs.GetAPI()->mapGetIntArray(clipinfo, kf_key, &err1);
 		const char *kfs_path = vs.GetAPI()->mapGetData(clipinfo, kf_key, 0, &err2);
 		if (err1 && err2)
-			throw VapoursynthError("Error getting keyframes from returned VSMap");
+			throw VapourSynthError("Error getting keyframes from returned VSMap");
 
 		if (!err1) {
 			keyframes.reserve(numkf);
@@ -199,7 +199,7 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		} else {
 			int kfs_path_size = vs.GetAPI()->mapGetDataSize(clipinfo, kf_key, 0, &err1);
 			if (err1)
-				throw VapoursynthError("Error getting size of keyframes path");
+				throw VapourSynthError("Error getting size of keyframes path");
 
 			try {
 				keyframes = agi::keyframe::Load(config::path->Decode(std::string(kfs_path, size_t(kfs_path_size))));
@@ -213,11 +213,11 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		const int64_t *tcs = vs.GetAPI()->mapGetIntArray(clipinfo, tc_key, &err1);
 		const char *tcs_path = vs.GetAPI()->mapGetData(clipinfo, tc_key, 0, &err2);
 		if (err1 && err2)
-			throw VapoursynthError("Error getting timecodes from returned map");
+			throw VapourSynthError("Error getting timecodes from returned map");
 
 		if (!err1) {
 			if (numtc != vi->numFrames)
-				throw VapoursynthError("Number of returned timecodes does not match number of frames");
+				throw VapourSynthError("Number of returned timecodes does not match number of frames");
 
 			std::vector<int> timecodes;
 			timecodes.reserve(numtc);
@@ -228,13 +228,13 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		} else {
 			int tcs_path_size = vs.GetAPI()->mapGetDataSize(clipinfo, tc_key, 0, &err1);
 			if (err1)
-				throw VapoursynthError("Error getting size of keyframes path");
+				throw VapourSynthError("Error getting size of keyframes path");
 
 			try {
 				fps = agi::vfr::Framerate(config::path->Decode(std::string(tcs_path, size_t(tcs_path_size))));
 			} catch (agi::Exception const& e) {
 				// Throw an error here unlike with keyframes since the timecodes not being loaded might not be immediately noticeable
-				throw VapoursynthError("Failed to open timecodes file specified by script: " + e.GetMessage());
+				throw VapourSynthError("Failed to open timecodes file specified by script: " + e.GetMessage());
 			}
 		}
 	}
@@ -245,7 +245,7 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 
 	const VSMap *props = vs.GetAPI()->getFramePropertiesRO(frame);
 	if (props == nullptr)
-		throw VapoursynthError("Couldn't get frame properties");
+		throw VapourSynthError("Couldn't get frame properties");
 	int64_t sarn = vs.GetAPI()->mapGetInt(props, "_SARNum", 0, &err1);
 	int64_t sard = vs.GetAPI()->mapGetInt(props, "_SARDen", 0, &err2);
 	if (!err1 && !err2) {
@@ -262,11 +262,11 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		// Convert to RGB24 format
 		VSPlugin *resize = vs.GetAPI()->getPluginByID(VSH_RESIZE_PLUGIN_ID, vs.GetScriptAPI()->getCore(script));
 		if (resize == nullptr)
-			throw VapoursynthError("Couldn't find resize plugin");
+			throw VapourSynthError("Couldn't find resize plugin");
 
 		VSMap *args = vs.GetAPI()->createMap();
 		if (args == nullptr)
-			throw VapoursynthError("Failed to create argument map");
+			throw VapourSynthError("Failed to create argument map");
 
 		vs.GetAPI()->mapSetNode(args, "clip", node, maAppend);
 		vs.GetAPI()->mapSetInt(args, "format", pfRGB24, maAppend);
@@ -299,7 +299,7 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 		const VSFrame *rgbframe = GetVSFrame(0);
 		vs.GetAPI()->freeFrame(rgbframe);
 	}
-} catch (VapoursynthError const& err) {     // for try inside of function. We need both here since we need to catch errors from the VapoursynthWrap constructor.
+} catch (VapourSynthError const& err) {     // for try inside of function. We need both here since we need to catch errors from the VapourSynthWrap constructor.
 	if (node != nullptr)
 		vs.GetAPI()->freeNode(node);
 	if (script != nullptr)
@@ -307,27 +307,27 @@ VapoursynthVideoProvider::VapoursynthVideoProvider(agi::fs::path const& filename
 	throw err;
 }
 }
-catch (VapoursynthError const& err) {    // for the entire constructor
-	throw VideoProviderError(agi::format("Vapoursynth error: %s", err.GetMessage()));
+catch (VapourSynthError const& err) {    // for the entire constructor
+	throw VideoProviderError(agi::format("VapourSynth error: %s", err.GetMessage()));
 }
 
-const VSFrame *VapoursynthVideoProvider::GetVSFrame(int n) {
+const VSFrame *VapourSynthVideoProvider::GetVSFrame(int n) {
 	char errorMsg[1024];
 	const VSFrame *frame = vs.GetAPI()->getFrame(n, node, errorMsg, sizeof(errorMsg));
 	if (frame == nullptr) {
-		throw VapoursynthError(agi::format("Error getting frame: %s", errorMsg));
+		throw VapourSynthError(agi::format("Error getting frame: %s", errorMsg));
 	}
 	return frame;
 }
 
-void VapoursynthVideoProvider::GetFrame(int n, VideoFrame &out) {
+void VapourSynthVideoProvider::GetFrame(int n, VideoFrame &out) {
 	std::lock_guard<std::mutex> lock(vs.GetMutex());
 
 	const VSFrame *frame = GetVSFrame(n);
 
 	const VSVideoFormat *format = vs.GetAPI()->getVideoFrameFormat(frame);
 	if (format->colorFamily != cfRGB || format->numPlanes != 3 || format->bitsPerSample != 8 || format->subSamplingH != 0 || format->subSamplingW != 0) {
-		throw VapoursynthError("Frame not in RGB24 format");
+		throw VapourSynthError("Frame not in RGB24 format");
 	}
 
 	out.width = vs.GetAPI()->getFrameWidth(frame, 0);
@@ -359,7 +359,7 @@ void VapoursynthVideoProvider::GetFrame(int n, VideoFrame &out) {
 	vs.GetAPI()->freeFrame(frame);
 }
 
-VapoursynthVideoProvider::~VapoursynthVideoProvider() {
+VapourSynthVideoProvider::~VapourSynthVideoProvider() {
 	if (node != nullptr) {
 		vs.GetAPI()->freeNode(node);
 	}
@@ -370,7 +370,7 @@ VapoursynthVideoProvider::~VapoursynthVideoProvider() {
 }
 
 namespace agi { class BackgroundRunner; }
-std::unique_ptr<VideoProvider> CreateVapoursynthVideoProvider(agi::fs::path const& path, std::string const& colormatrix, agi::BackgroundRunner *br) {
-	return agi::make_unique<VapoursynthVideoProvider>(path, colormatrix, br);
+std::unique_ptr<VideoProvider> CreateVapourSynthVideoProvider(agi::fs::path const& path, std::string const& colormatrix, agi::BackgroundRunner *br) {
+	return agi::make_unique<VapourSynthVideoProvider>(path, colormatrix, br);
 }
 #endif // WITH_VAPOURSYNTH
diff --git a/subprojects/vapoursynth.wrap b/subprojects/vapoursynth.wrap
index 592446ccf..1db0de4a5 100644
--- a/subprojects/vapoursynth.wrap
+++ b/subprojects/vapoursynth.wrap
@@ -1,4 +1,4 @@
 [wrap-git]
-url = https://github.com/Vapoursynth/vapoursynth.git
+url = https://github.com/vapoursynth/vapoursynth.git
 revision = R59
 patch_directory = vapoursynth
diff --git a/tools/osx-bundle.sh b/tools/osx-bundle.sh
index f8d4a682e..a1563a481 100755
--- a/tools/osx-bundle.sh
+++ b/tools/osx-bundle.sh
@@ -61,7 +61,12 @@ echo "---- Copying dictionaries ----"
 if test -f "${DICT_DIR}"; then
   cp -v "${DICT_DIR}/*" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
 else
-  echo "Specified dictionary directory ${DICT_DIR} not found!"
+  echo "Specified dictionary directory ${DICT_DIR} not found. Downloading dictionaries:"
+  mkdir "${BUILD_DIR}/dictionaries"
+  curl -L "https://downloads.sourceforge.net/project/openofficeorg.mirror/contrib/dictionaries/en_US.zip" -o "${BUILD_DIR}/dictionaries/en_US.zip"
+  unzip "${BUILD_DIR}/dictionaries/en_US.zip" -d "${BUILD_DIR}/dictionaries"
+  cp -v "${BUILD_DIR}/dictionaries/en_US.aff" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
+  cp -v "${BUILD_DIR}/dictionaries/en_US.dic" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
 fi
 
 echo
diff --git a/tools/win-installer-setup.ps1 b/tools/win-installer-setup.ps1
index 37bc974ed..b5a20b19e 100644
--- a/tools/win-installer-setup.ps1
+++ b/tools/win-installer-setup.ps1
@@ -63,13 +63,60 @@ if (!(Test-Path VSFilter)) {
 	Set-Location $DepsDir
 }
 
+### VapourSynth plugins
+
+# L-SMASH-Works
+if (!(Test-Path L-SMASH-Works)) {
+	New-Item -ItemType Directory L-SMASH-Works
+	$lsmasReleases = Invoke-WebRequest "https://api.github.com/repos/AkarinVS/L-SMASH-Works/releases/latest" -Headers $GitHeaders -UseBasicParsing | ConvertFrom-Json
+	$lsmasUrl = "https://github.com/AkarinVS/L-SMASH-Works/releases/download/" + $lsmasReleases.tag_name + "/release-x86_64-cachedir-cwd.zip"
+	Invoke-WebRequest $lsmasUrl -OutFile release-x86_64-cachedir-cwd.zip -UseBasicParsing
+	Expand-Archive -LiteralPath release-x86_64-cachedir-cwd.zip -DestinationPath L-SMASH-Works
+	Remove-Item release-x86_64-cachedir-cwd.zip
+}
+
+# bestaudiosource
+if (!(Test-Path bestaudiosource)) {
+	$basDir = New-Item -ItemType Directory bestaudiosource
+	Set-Location $basDir
+	$basReleases = Invoke-WebRequest "https://api.github.com/repos/vapoursynth/bestaudiosource/releases/latest" -Headers $GitHeaders -UseBasicParsing | ConvertFrom-Json
+	$basUrl = $basReleases.assets[0].browser_download_url
+	Invoke-WebRequest $basUrl -OutFile bas-r1.7z -UseBasicParsing
+	7z x bas-r1.7z
+	Remove-Item bas-r1.7z
+	Set-Location $DepsDir
+}
+
+# SCXVid
+if (!(Test-Path SCXVid)) {
+	$scxDir = New-Item -ItemType Directory SCXVid
+	Set-Location $scxDir
+	$scxReleases = Invoke-WebRequest "https://api.github.com/repos/dubhater/vapoursynth-scxvid/releases/latest" -Headers $GitHeaders -UseBasicParsing | ConvertFrom-Json
+	$scxUrl = "https://github.com/dubhater/vapoursynth-scxvid/releases/download/" + $scxReleases.tag_name + "/vapoursynth-scxvid-v1-win64.7z"
+	Invoke-WebRequest $scxUrl -OutFile vapoursynth-scxvid-v1-win64.7z -UseBasicParsing
+	7z x vapoursynth-scxvid-v1-win64.7z
+	Remove-Item vapoursynth-scxvid-v1-win64.7z
+	Set-Location $DepsDir
+}
+
+# WWXD
+if (!(Test-Path WWXD)) {
+	New-Item -ItemType Directory WWXD
+	$wwxdReleases = Invoke-WebRequest "https://api.github.com/repos/dubhater/vapoursynth-wwxd/releases/latest" -Headers $GitHeaders -UseBasicParsing | ConvertFrom-Json
+	$wwxdUrl = "https://github.com/dubhater/vapoursynth-wwxd/releases/download/" + $wwxdReleases.tag_name + "/libwwxd64.dll"
+	Invoke-WebRequest $wwxdUrl -OutFile WWXD/libwwxd64.dll -UseBasicParsing
+}
+
+
 # ffi-experiments
 if (!(Test-Path ffi-experiments)) {
 	Get-Command "moonc" # check to ensure Moonscript is present
 	git clone https://github.com/arch1t3cht/ffi-experiments.git
 	Set-Location ffi-experiments
 	meson build -Ddefault_library=static
+	if(!$?) { Exit $LASTEXITCODE }
 	meson compile -C build
+	if(!$?) { Exit $LASTEXITCODE }
 	Set-Location $DepsDir
 }
 
@@ -79,12 +126,21 @@ if (!(Test-Path VC_redist)) {
 	Invoke-WebRequest https://aka.ms/vs/17/release/VC_redist.x64.exe -OutFile "$redistDir\VC_redist.x64.exe" -UseBasicParsing
 }
 
-# TODO dictionaries
+# dictionaries
+if (!(Test-Path dictionaries)) {
+	New-Item -ItemType Directory dictionaries
+	[Net.ServicePointManager]::SecurityProtocol = "Tls12" 	# Needed since otherwise downloading fails in some places like on the GitHub CI: https://stackoverflow.com/a/66614041/4730656
+	Invoke-WebRequest https://downloads.sourceforge.net/project/openofficeorg.mirror/contrib/dictionaries/en_US.zip -UserAgent "Wget" -OutFile en_US.zip -UseBasicParsing
+	Expand-Archive -LiteralPath en_US.zip -DestinationPath dictionaries
+	Remove-Item en_US.zip
+}
 
 # localization
 Set-Location $BuildRoot
 meson compile aegisub-gmo
+if(!$?) { Exit $LASTEXITCODE }
 
 # Invoke InnoSetup
 $IssUrl = Join-Path $InstallerDir "aegisub_depctrl.iss"
 iscc $IssUrl
+if(!$?) { Exit $LASTEXITCODE }
\ No newline at end of file