Clean up min fragment duration

README.md

@@ -118,7 +118,7 @@ interface MuxerOptions {
     firstTimestampBehavior?: 'strict' | 'offset' | 'cross-track-offset',
 
     // The minimum duration of each fragment in seconds. Only applicable when 
-    // `fastStart` is set to `'fragmented'`. Default is 1.0.
+    // `fastStart` is set to `'fragmented'`. Default is 1.
     minFragmentDuration?: number
 }
 ```
@@ -161,7 +161,9 @@ This option specifies where the data created by the muxer will be written. The o
     default chunk size of 16 MiB, which can be overridden by manually setting `chunkSize` to the desired byte length.
 
     If you want to use this target for *live-streaming*, i.e. playback before muxing has finished, you also need to set
-    `fastStart: 'fragmented'`. If implementing live-streaming, also consider setting `minFragmentDuration` to a value that is appropriate for your use case (default value is 1 second). A new fragment is emitted when a keyframe is encountered after the duration of the buffered data has reached `minFragmentDuration` seconds.
+    `fastStart: 'fragmented'`. Also consider setting `minFragmentDuration` to a value that is appropriate for your use
+    case and latency requirements (default value is 1 second). A new fragment is emitted when a keyframe is encountered
+    after the duration of the buffered data has reached `minFragmentDuration` seconds.
 
     Usage example:
     ```js

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mp4-muxer",
-  "version": "5.2.1",
+  "version": "5.2.0",
   "description": "MP4 multiplexer in pure TypeScript with support for WebCodecs API, video & audio.",
   "main": "./build/mp4-muxer.js",
   "module": "./build/mp4-muxer.mjs",

src/muxer.ts

@@ -42,7 +42,7 @@ type Mp4MuxerOptions<T extends Target> =  {
 		expectedAudioChunks?: number
 	},
 	firstTimestampBehavior?: FirstTimestampBehavior,
-	fragmentedChunkDuration?: number
+	minFragmentDuration?: number
 };
 
 export interface Track {
@@ -240,6 +240,13 @@ export class Muxer<T extends Target> {
 		} else if (![false, 'in-memory', 'fragmented'].includes(options.fastStart)) {
 			throw new TypeError(`'fastStart' option must be false, 'in-memory', 'fragmented' or an object.`);
 		}
+
+		if (
+			options.minFragmentDuration !== undefined
+			&& (!Number.isFinite(options.minFragmentDuration) || options.minFragmentDuration < 0)
+		) {
+			throw new TypeError(`'minFragmentDuration' must be a non-negative number.`);
+		}
 	}
 
 	#writeHeader() {
@@ -682,7 +689,7 @@ export class Muxer<T extends Target> {
 
 			if (this.#options.fastStart === 'fragmented') {
 				let mostImportantTrack = this.#videoTrack ?? this.#audioTrack;
-				const chunkDuration = this.#options.fragmentedChunkDuration ?? 1.0;
+				const chunkDuration = this.#options.minFragmentDuration ?? 1;
 				if (track === mostImportantTrack && sample.type === 'key' && currentChunkDuration >= chunkDuration) {
 					beginNewChunk = true;
 					this.#finalizeFragment();