diff --git a/src/lib/components/functional/FormatDropdown.svelte b/src/lib/components/functional/FormatDropdown.svelte
index 4e665ab..7f6ce32 100644
--- a/src/lib/components/functional/FormatDropdown.svelte
+++ b/src/lib/components/functional/FormatDropdown.svelte
@@ -614,6 +614,7 @@
 									type="checkbox"
 									class="!w-fit"
 									bind:checked={imageSequenceTransparency}
+									disabled={!imageSequence}
 								/>
 								<label for="extract-sequence" class="text-sm">
 									{m["convert.image_sequence.transparency"]()}
diff --git a/src/lib/converters/ffmpeg/ffmpeg.animated.ts b/src/lib/converters/ffmpeg/ffmpeg.animated.ts
index aec17e4..c743d73 100644
--- a/src/lib/converters/ffmpeg/ffmpeg.animated.ts
+++ b/src/lib/converters/ffmpeg/ffmpeg.animated.ts
@@ -22,7 +22,7 @@ export function buildImageSequenceCommand(
 	const isAnimatedImage = animatedImageFormats.includes(outputFormat);
 	const enableTransparency = settings.imageSequenceTransparency ?? false;
 
-	if (videoFormats.includes(outputFormat)) {
+	if (videoFormats.includes(outputFormat) && !isAnimatedImage) {
 		const fpsFilter = `fps=${settings.imageSequenceFPS || 15}`;
 		const blackCompositeFilter =
 			`color=c=black,format=rgb24[bg];` +
@@ -61,7 +61,7 @@ export function buildImageSequenceCommand(
 			baseArgs.push("-plays", "0");
 			if (enableTransparency) baseArgs.push("-pix_fmt", "rgba");
 		} else if (outputFormat === "webp") {
-			if (enableTransparency) baseArgs.push("-pix_fmt", "rgba");
+			if (enableTransparency) baseArgs.push("-pix_fmt", "bgra");
 		}
 	} else {
 		const pixFmt = enableTransparency ? "yuva420p" : "yuv420p";
diff --git a/src/lib/converters/ffmpeg/ffmpeg.codecs.ts b/src/lib/converters/ffmpeg/ffmpeg.codecs.ts
index b3c1447..4149862 100644
--- a/src/lib/converters/ffmpeg/ffmpeg.codecs.ts
+++ b/src/lib/converters/ffmpeg/ffmpeg.codecs.ts
@@ -112,11 +112,6 @@ export const toArgs = (ext: string, isAlac: boolean = false): string[] => {
 			break;
 		}
 
-		case "libvpx": {
-			args.push("-c:v", "libvpx-vp9");
-			break;
-		}
-
 		case "mpeg2video": {
 			// for mpeg, mpg, vob, mxf
 			if (ext === ".mxf") args.push("-ar", "48000"); // force 48kHz sample rate