diff options
Diffstat (limited to 'apps/web/src/lib/media/audio-mastering.ts')
| -rw-r--r-- | apps/web/src/lib/media/audio-mastering.ts | 206 |
1 files changed, 103 insertions, 103 deletions
diff --git a/apps/web/src/lib/media/audio-mastering.ts b/apps/web/src/lib/media/audio-mastering.ts index 29af223b..f901c3bf 100644 --- a/apps/web/src/lib/media/audio-mastering.ts +++ b/apps/web/src/lib/media/audio-mastering.ts @@ -1,103 +1,103 @@ -const MASTER_LIMITER_THRESHOLD_DB = -1; -const MASTER_LIMITER_KNEE_DB = 0; -const MASTER_LIMITER_RATIO = 20; -const MASTER_LIMITER_ATTACK_SECONDS = 0.001; -const MASTER_LIMITER_RELEASE_SECONDS = 0.12; -const MASTER_OUTPUT_HEADROOM = 0.98; - -export function getAudioBufferPeak({ - audioBuffer, -}: { - audioBuffer: AudioBuffer; -}): number { - let peak = 0; - - for (let channel = 0; channel < audioBuffer.numberOfChannels; channel++) { - const channelData = audioBuffer.getChannelData(channel); - for (let index = 0; index < channelData.length; index++) { - const magnitude = Math.abs(channelData[index]); - if (magnitude > peak) { - peak = magnitude; - } - } - } - - return peak; -} - -export function createAudioMasteringChain({ - audioContext, - destination, -}: { - audioContext: AudioContext | OfflineAudioContext; - destination: AudioNode; -}): { - input: GainNode; -} { - const input = audioContext.createGain(); - const limiter = audioContext.createDynamicsCompressor(); - const outputGain = audioContext.createGain(); - - limiter.threshold.value = MASTER_LIMITER_THRESHOLD_DB; - limiter.knee.value = MASTER_LIMITER_KNEE_DB; - limiter.ratio.value = MASTER_LIMITER_RATIO; - limiter.attack.value = MASTER_LIMITER_ATTACK_SECONDS; - limiter.release.value = MASTER_LIMITER_RELEASE_SECONDS; - outputGain.gain.value = MASTER_OUTPUT_HEADROOM; - - input.connect(limiter); - limiter.connect(outputGain); - outputGain.connect(destination); - - return { input }; -} - -export async function applyAudioMasteringToBuffer({ - audioBuffer, -}: { - audioBuffer: AudioBuffer; -}): Promise<AudioBuffer> { - if (getAudioBufferPeak({ audioBuffer }) <= MASTER_OUTPUT_HEADROOM) { - return audioBuffer; - } - - const offlineContext = new OfflineAudioContext( - audioBuffer.numberOfChannels, - Math.max(1, audioBuffer.length), - audioBuffer.sampleRate, - ); - const source = offlineContext.createBufferSource(); - source.buffer = audioBuffer; - - const { input } = createAudioMasteringChain({ - audioContext: offlineContext, - destination: offlineContext.destination, - }); - source.connect(input); - source.start(0); - - const renderedBuffer = await offlineContext.startRendering(); - clampAudioBufferPeak({ - audioBuffer: renderedBuffer, - maxPeak: MASTER_OUTPUT_HEADROOM, - }); - return renderedBuffer; -} - -function clampAudioBufferPeak({ - audioBuffer, - maxPeak, -}: { - audioBuffer: AudioBuffer; - maxPeak: number; -}): void { - for (let channel = 0; channel < audioBuffer.numberOfChannels; channel++) { - const channelData = audioBuffer.getChannelData(channel); - for (let index = 0; index < channelData.length; index++) { - channelData[index] = Math.max( - -maxPeak, - Math.min(maxPeak, channelData[index]), - ); - } - } -} +const MASTER_LIMITER_THRESHOLD_DB = -1;
+const MASTER_LIMITER_KNEE_DB = 0;
+const MASTER_LIMITER_RATIO = 20;
+const MASTER_LIMITER_ATTACK_SECONDS = 0.001;
+const MASTER_LIMITER_RELEASE_SECONDS = 0.12;
+const MASTER_OUTPUT_HEADROOM = 0.98;
+
+export function getAudioBufferPeak({
+ audioBuffer,
+}: {
+ audioBuffer: AudioBuffer;
+}): number {
+ let peak = 0;
+
+ for (let channel = 0; channel < audioBuffer.numberOfChannels; channel++) {
+ const channelData = audioBuffer.getChannelData(channel);
+ for (let index = 0; index < channelData.length; index++) {
+ const magnitude = Math.abs(channelData[index]);
+ if (magnitude > peak) {
+ peak = magnitude;
+ }
+ }
+ }
+
+ return peak;
+}
+
+export function createAudioMasteringChain({
+ audioContext,
+ destination,
+}: {
+ audioContext: AudioContext | OfflineAudioContext;
+ destination: AudioNode;
+}): {
+ input: GainNode;
+} {
+ const input = audioContext.createGain();
+ const limiter = audioContext.createDynamicsCompressor();
+ const outputGain = audioContext.createGain();
+
+ limiter.threshold.value = MASTER_LIMITER_THRESHOLD_DB;
+ limiter.knee.value = MASTER_LIMITER_KNEE_DB;
+ limiter.ratio.value = MASTER_LIMITER_RATIO;
+ limiter.attack.value = MASTER_LIMITER_ATTACK_SECONDS;
+ limiter.release.value = MASTER_LIMITER_RELEASE_SECONDS;
+ outputGain.gain.value = MASTER_OUTPUT_HEADROOM;
+
+ input.connect(limiter);
+ limiter.connect(outputGain);
+ outputGain.connect(destination);
+
+ return { input };
+}
+
+export async function applyAudioMasteringToBuffer({
+ audioBuffer,
+}: {
+ audioBuffer: AudioBuffer;
+}): Promise<AudioBuffer> {
+ if (getAudioBufferPeak({ audioBuffer }) <= MASTER_OUTPUT_HEADROOM) {
+ return audioBuffer;
+ }
+
+ const offlineContext = new OfflineAudioContext(
+ audioBuffer.numberOfChannels,
+ Math.max(1, audioBuffer.length),
+ audioBuffer.sampleRate,
+ );
+ const source = offlineContext.createBufferSource();
+ source.buffer = audioBuffer;
+
+ const { input } = createAudioMasteringChain({
+ audioContext: offlineContext,
+ destination: offlineContext.destination,
+ });
+ source.connect(input);
+ source.start(0);
+
+ const renderedBuffer = await offlineContext.startRendering();
+ clampAudioBufferPeak({
+ audioBuffer: renderedBuffer,
+ maxPeak: MASTER_OUTPUT_HEADROOM,
+ });
+ return renderedBuffer;
+}
+
+function clampAudioBufferPeak({
+ audioBuffer,
+ maxPeak,
+}: {
+ audioBuffer: AudioBuffer;
+ maxPeak: number;
+}): void {
+ for (let channel = 0; channel < audioBuffer.numberOfChannels; channel++) {
+ const channelData = audioBuffer.getChannelData(channel);
+ for (let index = 0; index < channelData.length; index++) {
+ channelData[index] = Math.max(
+ -maxPeak,
+ Math.min(maxPeak, channelData[index]),
+ );
+ }
+ }
+}
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