atlas-iac/services/bstein-dev-home/av-observer/activity-worklet.js

// A cumulative, one-credit metadata reporter: never copies or sends audio.
class Activity extends AudioWorkletProcessor {
    constructor(options) {
        super(); this.frames=0; this.inputFrames=0; this.zeroFrames=0;
        this.energy=0; this.peak=0; this.credit=true; this.next=0; this.stopped=false;
        this.watch=options?.processorOptions?.continuityWatch===true;
        this.startedFrame=this.watch?currentFrame:0;this.lastAckFrame=this.startedFrame;
        this.port.onmessage=({data})=>{
            if(data==='ack'){this.credit=true;if(this.watch)this.lastAckFrame=currentFrame;}
            if(data==='stop')this.stopped=true;
        };
    }
    process(inputs,outputs) {
        if(this.stopped)return false;
        if(this.watch) {
            // Long watches require a live UI owner. Withheld ACKs stop work
            // autonomously; they never renew the fixed ten-hour deadline.
            const age=currentFrame-this.startedFrame,unacked=currentFrame-this.lastAckFrame;
            if(!Number.isSafeInteger(age)||age<0||unacked<0||age>=sampleRate*36025||unacked>sampleRate*10) {
                this.stopped=true;this.port.postMessage({watchStopped:true});return false;
            }
        } else if(this.frames >= sampleRate*125)return false;
        const block=outputs[0]?.[0]?.length ?? 128;
        const samples=inputs[0]?.[0];
        this.frames+=block;
        if(samples) for(const value of samples) {
            this.inputFrames++; this.energy+=value*value;
            this.peak=Math.max(this.peak,Math.abs(value));
            if(value===0)this.zeroFrames++;
        }
        // Output is left at zero: no monitoring/playback or acoustic feedback.
        if(this.credit && this.frames>=this.next) {
            this.port.postMessage({inputFrames:this.inputFrames,processedFrames:this.frames,
                exactZeroFrames:this.zeroFrames,rms:this.inputFrames ? Math.sqrt(this.energy/this.inputFrames) : 0,
                peak:this.peak,sampleRate});
            this.credit=false; this.next=this.frames+sampleRate;
        }
        return true;
    }
}
registerProcessor('av-activity',Activity);