use sexier audio waveform

This commit is contained in:
Arjun Patel
2026-06-11 09:55:04 -07:00
parent cf94003b3f
commit 8ed8e2cccb
7 changed files with 248 additions and 176 deletions
@@ -1,122 +0,0 @@
import { useEffect, useRef } from 'react';
interface AudioLevelBarsProps {
sourceNode: AudioNode;
}
const BAR_COUNT = 3;
const MIN_HEIGHT_PX = 6;
const MAX_HEIGHT_PX = 48;
// dB scale
const NOISE_FLOOR_DB = -50;
const DB_RANGE = -NOISE_FLOOR_DB; // 50dB dynamic range
// Asymmetric smoothing time constants
const ATTACK_MS = 30;
const RELEASE_MS = 300;
// Bar activation thresholds on the 0..1 normalized dB scale
const BAR_THRESHOLDS = [0.0, 0.15, 0.35];
/**
* 3-bar VU meter that visualizes audio levels from any AudioNode source.
* Works with both live MediaStream sources and MediaElement sources.
*
* Uses direct DOM manipulation with exponential smoothing on a dB scale
* for smooth, jitter-free animation independent of frame rate.
*/
export function AudioLevelBars({ sourceNode }: AudioLevelBarsProps) {
const barRefs = useRef<(HTMLDivElement | null)[]>([]);
useEffect(() => {
const ctx = sourceNode.context as AudioContext;
const analyser = ctx.createAnalyser();
analyser.fftSize = 256;
sourceNode.connect(analyser);
// Connect to destination via silent gain node — without this,
// Chromium suspends processing on disconnected audio graphs.
const silentGain = ctx.createGain();
silentGain.gain.value = 0;
analyser.connect(silentGain);
silentGain.connect(ctx.destination);
const dataArray = new Uint8Array(analyser.frequencyBinCount);
let smoothedLevel = 0;
let lastTime = performance.now();
let rafId = 0;
function tick() {
const now = performance.now();
const dt = now - lastTime;
lastTime = now;
analyser.getByteTimeDomainData(dataArray);
// Compute RMS of waveform (128 = silence baseline)
let sumSquares = 0;
for (let i = 0; i < dataArray.length; i++) {
const normalized = (dataArray[i] - 128) / 128;
sumSquares += normalized * normalized;
}
const rms = Math.sqrt(sumSquares / dataArray.length);
// Convert to dB, clamp to noise floor, normalize to 0..1
const db = rms > 0 ? 20 * Math.log10(rms) : NOISE_FLOOR_DB;
const normalizedDb = Math.max(0, (db - NOISE_FLOOR_DB) / DB_RANGE);
// Asymmetric exponential smoothing (frame-rate independent)
const timeConstant =
normalizedDb > smoothedLevel ? ATTACK_MS : RELEASE_MS;
const alpha = 1 - Math.exp(-dt / timeConstant);
smoothedLevel += alpha * (normalizedDb - smoothedLevel);
// Update bar heights via direct DOM writes
for (let i = 0; i < BAR_COUNT; i++) {
const el = barRefs.current[i];
if (!el) continue;
const threshold = BAR_THRESHOLDS[i];
const barLevel =
smoothedLevel <= threshold
? 0
: Math.min(1, (smoothedLevel - threshold) / (1 - threshold));
const height =
MIN_HEIGHT_PX + barLevel * (MAX_HEIGHT_PX - MIN_HEIGHT_PX);
el.style.height = `${height}px`;
}
rafId = requestAnimationFrame(tick);
}
rafId = requestAnimationFrame(tick);
return () => {
cancelAnimationFrame(rafId);
try {
sourceNode.disconnect(analyser);
analyser.disconnect(silentGain);
silentGain.disconnect(ctx.destination);
} catch {
// Nodes may already be disconnected
}
};
}, [sourceNode]);
return (
<div className="flex items-end gap-1.5">
{Array.from({ length: BAR_COUNT }, (_, i) => (
<div
key={i}
ref={(el) => {
barRefs.current[i] = el;
}}
className="w-1.5 rounded-full bg-green-400"
style={{ height: `${MIN_HEIGHT_PX}px` }}
/>
))}
</div>
);
}
@@ -0,0 +1,219 @@
import { useEffect, useRef } from 'react';
interface CenteredWaveformProps {
sourceNode: AudioNode;
/** Canvas size in CSS pixels. */
width?: number;
height?: number;
barWidth?: number;
gap?: number;
/** Bars are drawn with currentColor — set a text-* class to color them. */
className?: string;
}
// Voice band fanned out from the center bar (lows) to the edges (highs).
const MIN_FREQ_HZ = 100;
const MAX_FREQ_HZ = 4500;
// Analyser dB range mapped onto bar height; the defaults (-100/-30) waste
// most of the range on inaudible levels.
const MIN_DB = -75;
const MAX_DB = -25;
// Per-bar asymmetric smoothing time constants.
const ATTACK_MS = 40;
const RELEASE_MS = 220;
// Edge bars keep a fraction of their response so the whole row stays alive
// instead of only the middle moving.
const EDGE_RESPONSE = 0.3;
/**
* Centered live voice indicator, like a meeting app's "speaking" glyph.
* Bars fan out symmetrically from the middle: the center tracks the low
* frequencies where voice energy lives, the edges track the highs, and a
* cosine envelope tapers the response so the shape blooms from the center
* while someone speaks and settles into a dot line in silence.
*
* Renders on canvas with an rAF loop and no React state. No reduced-motion
* branch: the animation is signal-bearing audio feedback, not decoration,
* and only runs while audio is being captured or played.
*/
export function CenteredWaveform({
sourceNode,
width = 168,
height = 56,
barWidth = 4,
gap = 4,
className,
}: CenteredWaveformProps) {
const canvasRef = useRef<HTMLCanvasElement | null>(null);
useEffect(() => {
const canvasEl = canvasRef.current;
const ctx2d = canvasEl?.getContext('2d');
if (!canvasEl || !ctx2d) return;
// Rebind post-guard so the narrowed types carry into the closures below.
const canvas = canvasEl;
const drawCtx = ctx2d;
const { analyser, detach } = attachAnalyser(sourceNode, 512);
analyser.smoothingTimeConstant = 0.8;
analyser.minDecibels = MIN_DB;
analyser.maxDecibels = MAX_DB;
const bins = new Uint8Array(analyser.frequencyBinCount);
const stride = barWidth + gap;
// Odd count so one bar sits exactly at the center.
let barCount = Math.floor((width + gap) / stride);
if (barCount % 2 === 0) barCount -= 1;
const half = (barCount - 1) / 2;
// Map bar k (0 = center) to a frequency bin, log-spaced so the busy low
// end of the voice spectrum spreads across several bars.
const binHz = sourceNode.context.sampleRate / analyser.fftSize;
const binIndex = new Uint16Array(half + 1);
for (let k = 0; k <= half; k++) {
const freq =
MIN_FREQ_HZ *
Math.pow(MAX_FREQ_HZ / MIN_FREQ_HZ, half === 0 ? 0 : k / half);
binIndex[k] = Math.min(bins.length - 1, Math.round(freq / binHz));
}
const levels = new Float32Array(half + 1);
const ensureBackingStore = createBackingStoreScaler(
canvas,
drawCtx,
width,
height,
);
// currentColor, cached and refreshed periodically (theme switches show
// within 200ms) instead of paying a computed-style read every frame.
let fillColor = '';
let lastColorTime = 0;
let lastTime = performance.now();
let rafId = 0;
function tick() {
const now = performance.now();
const dt = now - lastTime;
lastTime = now;
analyser.getByteFrequencyData(bins);
for (let k = 0; k <= half; k++) {
const raw = bins[binIndex[k]] / 255;
const envelope =
half === 0
? 1
: EDGE_RESPONSE +
(1 - EDGE_RESPONSE) * Math.cos(((k / half) * Math.PI) / 2);
// Gamma keeps the floor quiet so silence reads as a dot line.
const target = Math.pow(raw, 1.4) * envelope;
// Asymmetric exponential smoothing (frame-rate independent)
const timeConstant = target > levels[k] ? ATTACK_MS : RELEASE_MS;
const alpha = 1 - Math.exp(-dt / timeConstant);
levels[k] += alpha * (target - levels[k]);
}
if (ensureBackingStore() || !fillColor || now - lastColorTime > 200) {
fillColor = getComputedStyle(canvas).color;
lastColorTime = now;
}
drawCtx.clearRect(0, 0, width, height);
drawCtx.fillStyle = fillColor;
const centerX = width / 2 - barWidth / 2;
drawCtx.beginPath();
for (let k = 0; k <= half; k++) {
const h = Math.max(barWidth, levels[k] * height);
const y = (height - h) / 2;
drawCtx.roundRect(centerX + k * stride, y, barWidth, h, barWidth / 2);
if (k > 0) {
drawCtx.roundRect(
centerX - k * stride,
y,
barWidth,
h,
barWidth / 2,
);
}
}
drawCtx.fill();
rafId = requestAnimationFrame(tick);
}
rafId = requestAnimationFrame(tick);
return () => {
cancelAnimationFrame(rafId);
detach();
};
}, [sourceNode, width, height, barWidth, gap]);
return (
<canvas ref={canvasRef} className={className} style={{ width, height }} />
);
}
/**
* Connects an AnalyserNode to the source for visualization.
*
* The analyser is routed to the destination via a silent gain node — without
* this, Chromium suspends processing on disconnected audio graphs.
*/
function attachAnalyser(
sourceNode: AudioNode,
fftSize: number,
): { analyser: AnalyserNode; detach: () => void } {
const ctx = sourceNode.context;
const analyser = ctx.createAnalyser();
analyser.fftSize = fftSize;
sourceNode.connect(analyser);
const silentGain = ctx.createGain();
silentGain.gain.value = 0;
analyser.connect(silentGain);
silentGain.connect(ctx.destination);
return {
analyser,
detach() {
try {
sourceNode.disconnect(analyser);
analyser.disconnect(silentGain);
silentGain.disconnect(ctx.destination);
} catch {
// Nodes may already be disconnected
}
},
};
}
/**
* Keeps the canvas backing store sized to width × height CSS pixels at the
* current devicePixelRatio, rescaling if the DPR changes (window moved
* between monitors). Call the returned function each frame; it returns true
* when the store was (re)initialized so callers can refresh cached state.
*/
function createBackingStoreScaler(
canvas: HTMLCanvasElement,
drawCtx: CanvasRenderingContext2D,
width: number,
height: number,
): () => boolean {
let dpr = 0;
return () => {
const currentDpr = window.devicePixelRatio || 1;
if (currentDpr === dpr) return false;
dpr = currentDpr;
canvas.width = Math.round(width * dpr);
canvas.height = Math.round(height * dpr);
drawCtx.setTransform(dpr, 0, 0, dpr, 0, 0);
return true;
};
}
@@ -1,7 +1,7 @@
import { useEffect, useRef, useState } from 'react';
import { Paperclip } from 'lucide-react';
import type { RecordingMode } from '@/hooks/use-recording-mode';
import { AudioLevelBars } from '@/components/audio/audio-level-bars';
import type { RecordingMode } from '@/stores/media-settings-store';
import { CenteredWaveform } from '@/components/audio/centered-waveform';
import { useAudioSource } from '@/components/audio/use-audio-source';
import { useObjectUrl } from '@/hooks/use-object-url';
import { AttachmentStrip } from '@/features/compose/attachment-strip';
@@ -67,7 +67,6 @@ function ReviewPlayback({
objectFit?: 'cover' | 'contain';
}) {
const objectUrl = useObjectUrl(blob);
const audioElRef = useRef<HTMLAudioElement | null>(null);
const [audioEl, setAudioEl] = useState<HTMLAudioElement | null>(null);
const audioSource = useAudioSource(isVideo ? null : audioEl);
@@ -87,17 +86,12 @@ function ReviewPlayback({
return (
<div className="flex flex-col items-center gap-3">
<audio
ref={(el) => {
audioElRef.current = el;
setAudioEl(el);
}}
src={objectUrl}
autoPlay
loop
/>
<audio ref={setAudioEl} src={objectUrl} autoPlay loop />
{audioSource ? (
<AudioLevelBars sourceNode={audioSource.sourceNode} />
<CenteredWaveform
sourceNode={audioSource.sourceNode}
className="text-white"
/>
) : (
<span className="text-sm text-white/60">Playing back audio...</span>
)}
@@ -198,10 +192,13 @@ export function RecordingOverlay({
) : null}
</div>
{/* Bottom center: audio level bars (recording with active stream) */}
{/* Bottom center: live waveform (recording with active stream) */}
{isRecording && recordingAudioSource && (
<div className="z-10 absolute bottom-15">
<AudioLevelBars sourceNode={recordingAudioSource.sourceNode} />
<CenteredWaveform
sourceNode={recordingAudioSource.sourceNode}
className="text-white"
/>
</div>
)}
@@ -1,5 +1,5 @@
import { useCallback, useEffect, useRef } from 'react';
import type { RecordingMode } from '@/hooks/use-recording-mode';
import type { RecordingMode } from '@/stores/media-settings-store';
const VIDEO_PREFERRED_MIME = 'video/webm;codecs=vp9,opus';
const VIDEO_FALLBACK_MIME = 'video/webm';
@@ -11,7 +11,7 @@ import { useDownloadUrl } from '@/hooks/use-download-url';
import { useTranscriptPlayback } from '@/hooks/use-transcript-playback';
import { TranscriptOverlay } from '@/features/particles/transcript-overlay';
import { Skeleton } from '@/components/ui/skeleton';
import { AudioLevelBars } from '@/components/audio/audio-level-bars';
import { CenteredWaveform } from '@/components/audio/centered-waveform';
import { useAudioSource } from '@/components/audio/use-audio-source';
import { useParticleAttachments } from '@/hooks/use-particle-attachments';
import { ParticleAttachments } from '@/features/particles/particle-attachments';
@@ -89,7 +89,7 @@ export const MediaParticleView = forwardRef<
currentTime,
);
// WORKAROUND: useAudioSource needs an audio element, but audioRef is only set after mount
// useAudioSource needs the audio element, but audioRef is only set after mount
const [audioEl, setAudioEl] = useState<HTMLAudioElement | null>(null);
const audioSource = useAudioSource(audioEl);
@@ -156,7 +156,10 @@ export const MediaParticleView = forwardRef<
{audioSource && (
<div className="z-10 absolute bottom-20">
<AudioLevelBars sourceNode={audioSource.sourceNode} />
<CenteredWaveform
sourceNode={audioSource.sourceNode}
className="text-white"
/>
</div>
)}
@@ -12,7 +12,7 @@ import {
SelectTrigger,
SelectValue,
} from '@/components/ui/select';
import { AudioLevelBars } from '@/components/audio/audio-level-bars';
import { CenteredWaveform } from '@/components/audio/centered-waveform';
import { useAudioSource } from '@/components/audio/use-audio-source';
import { useMediaDevices } from '@/hooks/use-media-devices';
import {
@@ -105,20 +105,17 @@ function FieldLabel({ children }: { children: React.ReactNode }) {
function InlineLevelMeter({ stream }: { stream: MediaStream | null }) {
const audioSource = useAudioSource(stream);
if (!audioSource) {
return (
<div className="flex h-3 items-end gap-1">
{[0, 1, 2].map((i) => (
<div key={i} className="bg-muted h-1 w-1 rounded-full" />
))}
</div>
);
return <div className="bg-muted h-3 w-20 rounded-sm opacity-50" />;
}
return (
<div className="flex h-3 items-end">
<div className="scale-[0.55] origin-right">
<AudioLevelBars sourceNode={audioSource.sourceNode} />
</div>
</div>
<CenteredWaveform
sourceNode={audioSource.sourceNode}
width={80}
height={12}
barWidth={2}
gap={3}
className="text-primary"
/>
);
}
@@ -1,22 +0,0 @@
import { useState, useCallback } from 'react';
export type RecordingMode = 'video' | 'audio';
const KEY = 'llink:recording-mode';
export function useRecordingMode(): [
RecordingMode,
(mode: RecordingMode) => void,
] {
const [mode, setModeState] = useState<RecordingMode>(() => {
const stored = localStorage.getItem(KEY);
return stored === 'audio' ? 'audio' : 'video';
});
const setMode = useCallback((m: RecordingMode) => {
localStorage.setItem(KEY, m);
setModeState(m);
}, []);
return [mode, setMode];
}