Fix empty audio trim range crashing conversion (fixes #486)

dev/convert.html

@@ -99,7 +99,7 @@
 			input,
 			output,
 			audio: {
-				discard: true,
+				forceTranscode: true,
 				//discard: true,
 				//codec: 'aac',
 				//forceTranscode: true,
@@ -162,6 +162,8 @@
 				}
 			},
 			trim: {
+				start: 30,
+				end: 35,
 				//start: -60,
 				//end: 60,
 				//start: -2,

src/conversion.ts

@@ -2113,6 +2113,12 @@ export class Conversion {
 						endFrame = Math.round((this._endTimestamp - sample.timestamp) * sample.sampleRate);
 					}
 
+					if (startFrame >= endFrame) {
+						// Sample lies wholly out of trim region
+						sample.close();
+						continue; // No break since we may be before the start
+					}
+
 					// Can't assign to "using" identifiers so we gotta do this
 					let finalSampleLet: AudioSample;
 					if (startFrame > 0 || endFrame < sample.numberOfFrames) {

src/sample.ts

@@ -2866,32 +2866,32 @@ export class AudioSample implements Disposable {
 	}
 
 	/**
-	 * Returns a new {@link AudioSample} containing only the frames in the range [startSample, endSample). Both bounds
+	 * Returns a new {@link AudioSample} containing only the frames in the range [startFrame, endFrame). Both bounds
 	 * must lie within this sample's range of frames. The returned sample's timestamp is shifted to match the start of
 	 * the trimmed section.
 	 */
-	trim(startSample: number, endSample = this.numberOfFrames) {
-		if (!Number.isInteger(startSample) || startSample < 0) {
-			throw new TypeError('startSample must be a non-negative integer.');
+	trim(startFrame: number, endFrame = this.numberOfFrames) {
+		if (!Number.isInteger(startFrame) || startFrame < 0) {
+			throw new TypeError('startFrame must be a non-negative integer.');
 		}
-		if (!Number.isInteger(endSample) || endSample < 0) {
-			throw new TypeError('endSample must be a non-negative integer.');
+		if (!Number.isInteger(endFrame) || endFrame < 0) {
+			throw new TypeError('endFrame must be a non-negative integer.');
 		}
-		if (startSample > this.numberOfFrames) {
-			throw new RangeError('startSample out of range.');
+		if (startFrame > this.numberOfFrames) {
+			throw new RangeError('startFrame out of range.');
 		}
-		if (endSample > this.numberOfFrames) {
-			throw new RangeError('endSample out of range.');
+		if (endFrame > this.numberOfFrames) {
+			throw new RangeError('endFrame out of range.');
 		}
-		if (endSample < startSample) {
-			throw new RangeError('endSample must not be less than startSample.');
+		if (endFrame < startFrame) {
+			throw new RangeError('endFrame must not be less than startFrame.');
 		}
 
 		if (this._closed) {
 			throw new Error('AudioSample is closed.');
 		}
 
-		const frameCount = endSample - startSample;
+		const frameCount = endFrame - startFrame;
 		const bytesPerSample = getBytesPerSample(this.format);
 
 		let data: Uint8Array;
@@ -2905,7 +2905,7 @@ export class AudioSample implements Disposable {
 					this.copyTo(data.subarray(i * planeSize, (i + 1) * planeSize), {
 						planeIndex: i,
 						format: this.format,
-						frameOffset: startSample,
+						frameOffset: startFrame,
 						frameCount,
 					});
 				}
@@ -2918,7 +2918,7 @@ export class AudioSample implements Disposable {
 				this.copyTo(data, {
 					planeIndex: 0,
 					format: this.format,
-					frameOffset: startSample,
+					frameOffset: startFrame,
 					frameCount,
 				});
 			}
@@ -2929,7 +2929,7 @@ export class AudioSample implements Disposable {
 			format: this.format,
 			sampleRate: this.sampleRate,
 			numberOfChannels: this.numberOfChannels,
-			timestamp: this.timestamp + startSample / this.sampleRate,
+			timestamp: this.timestamp + startFrame / this.sampleRate,
 		});
 	}