diff --git a/packages/win_installer/fragment_associations.iss b/packages/win_installer/fragment_associations.iss
index 2fe401baf..7e19a3340 100644
--- a/packages/win_installer/fragment_associations.iss
+++ b/packages/win_installer/fragment_associations.iss
@@ -64,6 +64,9 @@ Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedT
 Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".wav"; ValueData: ""; Flags: uninsdeletekey
 Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".ogg"; ValueData: ""; Flags: uninsdeletekey
 Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".avs"; ValueData: ""; Flags: uninsdeletekey
+Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".opus"; ValueData: ""; Flags: uninsdeletekey
+Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".h264"; ValueData: ""; Flags: uninsdeletekey
+Root: HKLM; Subkey: "SOFTWARE\Classes\Applications\aegisub{#ARCH}.exe\SupportedTypes"; ValueType: string; ValueName: ".hevc"; ValueData: ""; Flags: uninsdeletekey
 ; Class for general subtitle formats
 Root: HKLM; Subkey: "SOFTWARE\Classes\Aegisub.Subtitle.1"; ValueType: string; ValueName: ""; ValueData: "Aegisub subtitle file"; Flags: uninsdeletekey
 Root: HKLM; Subkey: "SOFTWARE\Classes\Aegisub.Subtitle.1"; ValueType: dword; ValueName: "EditFlags"; ValueData: $af0; Flags: uninsdeletekey
@@ -195,4 +198,6 @@ Root: HKLM; Subkey: "SOFTWARE\Classes\.m4a\OpenWithProgids"; ValueType: string;
 Root: HKLM; Subkey: "SOFTWARE\Classes\.wav\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Audio.1"; Flags: uninsdeletevalue
 Root: HKLM; Subkey: "SOFTWARE\Classes\.ogg\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Media.1"; Flags: uninsdeletevalue
 Root: HKLM; Subkey: "SOFTWARE\Classes\.avs\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Video.1"; Flags: uninsdeletevalue
-
+Root: HKLM; Subkey: "SOFTWARE\Classes\.opus\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Audio.1"; Flags: uninsdeletevalue
+Root: HKLM; Subkey: "SOFTWARE\Classes\.h264\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Video.1"; Flags: uninsdeletevalue
+Root: HKLM; Subkey: "SOFTWARE\Classes\.hevc\OpenWithProgids"; ValueType: string; ValueName: "Aegisub.Video.1"; Flags: uninsdeletevalue
diff --git a/src/command/audio.cpp b/src/command/audio.cpp
index d10491b07..de25d6454 100644
--- a/src/command/audio.cpp
+++ b/src/command/audio.cpp
@@ -80,7 +80,7 @@ struct audio_open final : public Command {
 	STR_HELP("Open an audio file")
 
 	void operator()(agi::Context *c) override {
-		auto str = from_wx(_("Audio Formats") + " (*.aac,*.ac3,*.ape,*.dts,*.flac,*.m4a,*.mka,*.mp3,*.mp4,*.ogg,*.w64,*.wav,*.wma)|*.aac;*.ac3;*.ape;*.dts;*.flac;*.m4a;*.mka;*.mp3;*.mp4;*.ogg;*.w64;*.wav;*.wma|"
+		auto str = from_wx(_("Audio Formats") + " (*.aac,*.ac3,*.ape,*.dts,*.flac,*.m4a,*.mka,*.mp3,*.mp4,*.ogg,*.opus,*.w64,*.wav,*.wma)|*.aac;*.ac3;*.ape;*.dts;*.flac;*.m4a;*.mka;*.mp3;*.mp4;*.ogg;*.opus;*.w64;*.wav;*.wma|"
 					+ _("Video Formats") + " (*.asf,*.avi,*.avs,*.d2v,*.m2ts,*.m4v,*.mkv,*.mov,*.mp4,*.mpeg,*.mpg,*.ogm,*.webm,*.wmv,*.ts)|*.asf;*.avi;*.avs;*.d2v;*.m2ts;*.m4v;*.mkv;*.mov;*.mp4;*.mpeg;*.mpg;*.ogm;*.webm;*.wmv;*.ts|"
 					+ _("All Files") + " (*.*)|*.*");
 		auto filename = OpenFileSelector(_("Open Audio File"), "Path/Last/Audio", "", "", str, c->parent);
diff --git a/src/command/video.cpp b/src/command/video.cpp
index fb2bcb0ba..d3ffaf7fe 100644
--- a/src/command/video.cpp
+++ b/src/command/video.cpp
@@ -564,7 +564,7 @@ struct video_open final : public Command {
 	STR_HELP("Open a video file")
 
 	void operator()(agi::Context *c) override {
-		auto str = from_wx(_("Video Formats") + " (*.asf,*.avi,*.avs,*.d2v,*.m2ts,*.m4v,*.mkv,*.mov,*.mp4,*.mpeg,*.mpg,*.ogm,*.webm,*.wmv,*.ts,*.y4m,*.yuv)|*.asf;*.avi;*.avs;*.d2v;*.m2ts;*.m4v;*.mkv;*.mov;*.mp4;*.mpeg;*.mpg;*.ogm;*.webm;*.wmv;*.ts;*.y4m;*.yuv|"
+		auto str = from_wx(_("Video Formats") + " (*.asf,*.avi,*.avs,*.d2v,*.h264,*.hevc,*.m2ts,*.m4v,*.mkv,*.mov,*.mp4,*.mpeg,*.mpg,*.ogm,*.webm,*.wmv,*.ts,*.y4m,*.yuv)|*.asf;*.avi;*.avs;*.d2v;*.h264;*.hevc;*.m2ts;*.m4v;*.mkv;*.mov;*.mp4;*.mpeg;*.mpg;*.ogm;*.webm;*.wmv;*.ts;*.y4m;*.yuv|"
 		         + _("All Files") + " (*.*)|*.*");
 		auto filename = OpenFileSelector(_("Open video file"), "Path/Last/Video", "", "", str, c->parent);
 		if (!filename.empty())
diff --git a/src/project.cpp b/src/project.cpp
index 312f86fe8..e2b78c319 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -412,6 +412,8 @@ void Project::LoadList(std::vector<agi::fs::path> const& files) {
 		".avi",
 		".avs",
 		".d2v",
+		".h264",
+		".hevc",
 		".m2ts",
 		".m4v",
 		".mkv",
@@ -449,6 +451,7 @@ void Project::LoadList(std::vector<agi::fs::path> const& files) {
 		".mka",
 		".mp3",
 		".ogg",
+		".opus",
 		".w64",
 		".wav",
 		".wma"