74 lines
3.6 KiB
JavaScript
74 lines
3.6 KiB
JavaScript
class PCMProcessor extends AudioWorkletProcessor {
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constructor() {
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super();
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this.buffer = new Float32Array(24000 * 30); // Pre-allocate buffer for ~30 seconds at 24kHz
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this.writeIndex = 0;
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this.readIndex = 0;
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this.pendingBytes = new Uint8Array(0); // Buffer for incomplete samples
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this.volume = 1.0; // Default volume (1.0 = 100%, 0.5 = 50%, etc.)
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this.port.onmessage = (event) => {
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if (event.data.pcmData) {
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// Combine any pending bytes with new data
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const newData = new Uint8Array(event.data.pcmData);
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const combined = new Uint8Array(this.pendingBytes.length + newData.length);
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combined.set(this.pendingBytes);
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combined.set(newData, this.pendingBytes.length);
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// Calculate how many complete 16-bit samples we have
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const completeSamples = Math.floor(combined.length / 2);
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const bytesToProcess = completeSamples * 2;
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if (completeSamples > 0) {
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// Process complete samples
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const int16Array = new Int16Array(combined.buffer.slice(0, bytesToProcess));
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// Write directly to circular buffer
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for (let i = 0; i < int16Array.length; i++) {
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// Expand buffer if needed
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if (this.writeIndex >= this.buffer.length) {
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const newBuffer = new Float32Array(this.buffer.length * 2);
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// Copy existing data maintaining order
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let sourceIndex = this.readIndex;
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let targetIndex = 0;
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while (sourceIndex !== this.writeIndex) {
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newBuffer[targetIndex++] = this.buffer[sourceIndex];
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sourceIndex = (sourceIndex + 1) % this.buffer.length;
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}
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this.buffer = newBuffer;
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this.readIndex = 0;
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this.writeIndex = targetIndex;
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}
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this.buffer[this.writeIndex] = int16Array[i] / 32768.0; // Convert 16-bit to float
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this.writeIndex = (this.writeIndex + 1) % this.buffer.length;
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}
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}
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// Store any remaining incomplete bytes
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if (combined.length > bytesToProcess) {
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this.pendingBytes = combined.slice(bytesToProcess);
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} else {
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this.pendingBytes = new Uint8Array(0);
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}
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} else if (event.data.volume !== undefined) {
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// Set volume (0.0 to 1.0, can go higher for amplification)
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this.volume = Math.max(0, event.data.volume);
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}
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};
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}
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process(inputs, outputs, parameters) {
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const output = outputs[0];
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if (output.length > 0 && this.readIndex !== this.writeIndex) {
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const channelData = output[0];
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for (let i = 0; i < channelData.length && this.readIndex !== this.writeIndex; i++) {
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channelData[i] = this.buffer[this.readIndex] * this.volume;
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this.readIndex = (this.readIndex + 1) % this.buffer.length;
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}
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}
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return true;
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}
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}
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registerProcessor('pcm-processor', PCMProcessor);
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