diff --git a/automation/vapoursynth/aegisub_vs.py b/automation/vapoursynth/aegisub_vs.py
index 3e37cb91f..dc354df03 100644
--- a/automation/vapoursynth/aegisub_vs.py
+++ b/automation/vapoursynth/aegisub_vs.py
@@ -308,15 +308,15 @@ def get_keyframes(filename: str, clip: vs.VideoNode, fallback: str | List[int],
 def check_audio(filename: str, **kwargs: Any) -> bool:
     """
     Checks whether the given file has an audio track by trying to open it with
-    BestAudioSource. Requires the `bas` plugin to return correct results, but
+    BestSource. Requires the `bs` plugin to return correct results, but
     won't crash if it's not installed.
-    Additional keyword arguments are passed on to BestAudioSource.
+    Additional keyword arguments are passed on to BestSource.
     """
     progress_set_message("Checking if the file has an audio track")
     progress_set_indeterminate()
     try:
-        ensure_plugin("bas", "BestAudioSource", "")
-        vs.core.bas.Source(source=filename, **kwargs)
+        ensure_plugin("bs", "BestSource", "")
+        vs.core.bs.AudioSource(source=filename, **kwargs)
         return True
     except AttributeError:
         pass
diff --git a/packages/win_installer/fragment_codecs.iss b/packages/win_installer/fragment_codecs.iss
index f71f74b31..cf71a43d7 100644
--- a/packages/win_installer/fragment_codecs.iss
+++ b/packages/win_installer/fragment_codecs.iss
@@ -7,6 +7,6 @@ DestDir: {app}; Source: {#DEPS_DIR}\AvisynthPlus64\x64\plugins\DirectShowSource.
 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}\BestSource\x64\BestSource.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/src/libresrc/default_config.json b/src/libresrc/default_config.json
index f2451d7ea..a41b528a1 100644
--- a/src/libresrc/default_config.json
+++ b/src/libresrc/default_config.json
@@ -338,7 +338,7 @@
 				"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\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()"
+				"Default Script" : "# This default script will load an audio file using BestSource.\n# It requires the `bs` plugin.\n\nimport vapoursynth as vs\nimport aegisub_vs as a\na.set_paths(locals())\n\na.ensure_plugin(\"bs\", \"BestSource\", \"To use Aegisub's default audio loader, the `bs` plugin for VapourSynth must be installed\")\nvs.core.bs.AudioSource(source=filename).set_output()"
 			}
 		},
 		"Avisynth" : {
diff --git a/src/libresrc/osx/default_config.json b/src/libresrc/osx/default_config.json
index 8a43c5423..2850fdd38 100644
--- a/src/libresrc/osx/default_config.json
+++ b/src/libresrc/osx/default_config.json
@@ -338,7 +338,7 @@
 				"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\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()"
+				"Default Script" : "# This default script will load an audio file using BestSource.\n# It requires the `bs` plugin.\n\nimport vapoursynth as vs\nimport aegisub_vs as a\na.set_paths(locals())\n\na.ensure_plugin(\"bs\", \"BestSource\", \"To use Aegisub's default audio loader, the `bs` plugin for VapourSynth must be installed\")\nvs.core.bs.AudioSource(source=filename).set_output()"
 			}
 		},
 		"Avisynth" : {
diff --git a/tools/win-installer-setup.ps1 b/tools/win-installer-setup.ps1
index d1a7b0987..1f52c409c 100644
--- a/tools/win-installer-setup.ps1
+++ b/tools/win-installer-setup.ps1
@@ -70,15 +70,15 @@ if (!(Test-Path 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
+# BestSource
+if (!(Test-Path BestSource)) {
+	$bsDir = New-Item -ItemType Directory BestSource
+	Set-Location $bsDir
+	$basReleases = Invoke-WebRequest "https://api.github.com/repos/vapoursynth/bestsource/releases/latest" -Headers $GitHeaders -UseBasicParsing | ConvertFrom-Json
+	$bsUrl = $basReleases.assets[0].browser_download_url
+	Invoke-WebRequest $bsUrl -OutFile bestsource.7z -UseBasicParsing
+	7z x bestsource.7z
+	Remove-Item bestsource.7z
 	Set-Location $DepsDir
 }