import { Codec } from "./types.js";
import { createRequire } from "module";
/**
* G.722 Codec - Wideband audio codec
* Payload type 9, 16kHz sample rate, 8kHz clock rate (RFC 3551)
*
* This implementation uses a native C++ addon wrapping the reference
* implementation from https://github.com/sippy/libg722
*
* License: Mix of public domain and permissive licenses (see LICENSE_G722)
*/
// Interface to describe the shape of our native addon
interface G722Addon {
new(): {
encode(pcm: Buffer): Buffer;
decode(encoded: Buffer): Buffer;
};
g722Enabled: boolean;
}
// Load the CommonJS loader module
const require = createRequire(import.meta.url);
const g722Loader = require('./g722-loader.cjs');
export class G722Codec implements Codec {
public readonly payloadType = 9;
public readonly name = "G722";
public readonly sampleRate = 16000;
public readonly clockRate = 8000; // As per RFC 3551
private nativeInstance: any = null;
constructor() {
if (!g722Loader.isAvailable()) {
const reason = g722Loader.getUnavailableReason();
const errorMsg = reason
? `G.722 codec not available: ${reason}. Set ENABLE_G722=1 during build to enable.`
: 'G.722 codec not compiled in. Set ENABLE_G722=1 during build.';
throw new Error(errorMsg);
}
try {
this.nativeInstance = new g722Loader.g722_addon.G722();
} catch (error) {
throw new Error(`Failed to initialize G.722 codec: ${error instanceof Error ? error.message : 'Unknown error'}`);
}
}
encode(pcm: Int16Array): Buffer {
if (!this.nativeInstance) {
throw new Error('G.722 codec not initialized');
}
// The native addon expects a raw Buffer, not a TypedArray view
const pcmBuffer = Buffer.from(pcm.buffer, pcm.byteOffset, pcm.byteLength);
return this.nativeInstance.encode(pcmBuffer);
}
decode(encoded: Buffer): Int16Array {
if (!this.nativeInstance) {
throw new Error('G.722 codec not initialized');
}
const pcmBuffer = this.nativeInstance.decode(encoded);
// Return an Int16Array view over the decoded Buffer
return new Int16Array(pcmBuffer.buffer, pcmBuffer.byteOffset, pcmBuffer.length / 2);
}
/**
* Check if G.722 codec is available
*/
static isAvailable(): boolean {
return g722Loader.isAvailable();
}
/**
* Get the reason why G.722 is not available (if applicable)
*/
static getUnavailableReason(): string | null {
return g722Loader.getUnavailableReason();
}
}
