Method run

tools/wav2maud.js:137–231

()

	}

	run() {
		const imaSamplesPerChunk = 129;
		const imaOutput = "ima" === this.output.format;

		let outputFile = new FILE(this.outputPath, "wb");

		let header = new DataView(new ArrayBuffer(12));
		header.setUint8(0, 'm'.charCodeAt(0));
		header.setUint8(1, 'a'.charCodeAt(0));
		header.setUint8(2, 1);		// version
		header.setUint8(3, this.output.bitsPerSample);
		header.setUint16(4, this.output.sampleRate, true);		// little-endian
		header.setUint8(6, this.output.numChannels);
		header.setUint8(7, imaOutput ? 1 : 0);		// sample format
		let sampleCount = Math.floor((this.wav.samples / this.wav.sampleRate) * this.output.sampleRate);
		if (imaOutput)
			sampleCount = Math.idiv(sampleCount, imaSamplesPerChunk) * imaSamplesPerChunk;		// quantize
		header.setUint32(8, sampleCount, true)
		outputFile.writeBuffer(header.buffer);

		let resampled = this.resampler.outputBuffer;
		let finalSamples = (8 === this.output.bitsPerSample) ? new Int8Array(this.wavSamples.length) : new Int16Array(this.wavSamples.length);

		let imaBuffer = new Int16Array(imaSamplesPerChunk);
		imaBuffer.samplesInBuffer = 0;

		let totalOut = 0;
		while (this.wav.samples) {
			// get next buffer of samples
			let use = this.wavSamples.length / this.wav.numChannels;
			if (use > this.wav.samples)
				use = this.wav.samples;
			use = Math.min(1024, use);
			this.wav.getSamples(this.wavSamples, use);

			// apply output sample rate
			use = this.resampler.resampler(use * this.wav.numChannels) / this.wav.numChannels;

			// apply output numChannels (stereo to mono)
			if ((2 == this.wav.numChannels) && (1 == this.output.numChannels)) {
				for (let i = 0, j = 0; i < use; i++, j += 2)
					resampled[i] = (resampled[j] + resampled[j + 1]) / 2;
			}

			// apply output bitsPerSample to generate finalSamples
			if (16 == this.output.bitsPerSample) {			// -32768 to 32767
				for (let i = 0, length = use * this.wav.numChannels; i < length; i++)
					finalSamples[i] = resampled[i];
			}
			else if (8 == this.output.bitsPerSample) {		// -128 to 127
				for (let i = 0, length = use * this.wav.numChannels; i < length; i++)
					finalSamples[i] = resampled[i] >> 8;
			}

			// output samples
			if ("uncompressed" === this.output.format) {
				let byteLength = use * ((this.output.bitsPerSample * this.output.numChannels) >> 3);
				outputFile.writeBuffer(finalSamples.buffer.slice(0, byteLength));