Fix faulty MP3 bitrate and frame size calculation (fixes #134)

dev/convert.html

@@ -24,9 +24,7 @@
 			chunked: true,
 			chunkSize: 2**20
 		});
-		const outputFormat = new Mediabunny.Mp4OutputFormat({
-			metadataFormat: 'mdta',
-		});
+		const outputFormat = new Mediabunny.Mp3OutputFormat({});
 
 		const button = document.createElement('button');
 		button.textContent = 'Cancel';

dev/demux.html

@@ -14,7 +14,18 @@
 			source: new Mediabunny.BlobSource(file),
 		});
 
-		console.log(await input.getMetadataTags());
+		console.log(await input.computeDuration());
+		return;
+
+		const audioTrack = await input.getPrimaryAudioTrack();
+		const sink = new Mediabunny.EncodedPacketSink(audioTrack);
+
+		for await (const packet of sink.packets()) {
+			console.log(packet)
+		}
+
+		console.log("Done")
+
 
 		/*