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Cache background image #100

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Merged
1egoman merged 3 commits into from
Sep 4, 2025
Merged

Cache background image #100

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004bc8d
feat: cache background image rather than refetch it every time it is …
1egoman Sep 4, 2025
a1b009d
feat: store imagedata instead of raw image, since createImageBitmap i…
1egoman Sep 4, 2025
e1399c3
docs(changeset): cache background image rather than refetch it every …
1egoman Sep 4, 2025
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5 changes: 5 additions & 0 deletions .changeset/legal-kings-fly.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
'@livekit/track-processors': patch
---

cache background image rather than refetch it every time it is enabled
33 changes: 18 additions & 15 deletions src/transformers/BackgroundTransformer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ export default class BackgroundProcessor extends VideoTransformer<BackgroundOpti

segmentationResults: vision.ImageSegmenterResult | undefined;

backgroundImage: ImageBitmap | null = null;
backgroundImageAndPath: { imageData: ImageBitmap, path: string } | null = null;

options: BackgroundOptions;

Expand Down Expand Up @@ -75,8 +75,8 @@ export default class BackgroundProcessor extends VideoTransformer<BackgroundOpti
});

// Skip loading the image here if update already loaded the image below
if (this.options?.imagePath && !this.backgroundImage) {
await this.loadBackground(this.options.imagePath).catch((err) =>
if (this.options?.imagePath) {
await this.loadAndSetBackground(this.options.imagePath).catch((err) =>
console.error('Error while loading processor background image: ', err),
);
}
Expand All @@ -88,21 +88,24 @@ export default class BackgroundProcessor extends VideoTransformer<BackgroundOpti
async destroy() {
await super.destroy();
await this.imageSegmenter?.close();
this.backgroundImage = null;
this.backgroundImageAndPath = null;
this.isFirstFrame = true;
}

async loadBackground(path: string) {
const img = new Image();
async loadAndSetBackground(path: string) {
if (!this.backgroundImageAndPath || this.backgroundImageAndPath?.path !== path) {
const img = new Image();

await new Promise((resolve, reject) => {
img.crossOrigin = 'Anonymous';
img.onload = () => resolve(img);
img.onerror = (err) => reject(err);
img.src = path;
});
const imageData = await createImageBitmap(img);
this.gl?.setBackgroundImage(imageData);
await new Promise((resolve, reject) => {
img.crossOrigin = 'Anonymous';
img.onload = () => resolve(img);
img.onerror = (err) => reject(err);
img.src = path;
});
const imageData = await createImageBitmap(img);
this.backgroundImageAndPath = { imageData, path };
}
this.gl?.setBackgroundImage(this.backgroundImageAndPath.imageData);
}

async transform(frame: VideoFrame, controller: TransformStreamDefaultController<VideoFrame>) {
Expand Down Expand Up @@ -200,7 +203,7 @@ export default class BackgroundProcessor extends VideoTransformer<BackgroundOpti

this.gl?.setBlurRadius(opts.blurRadius ?? null);
if (opts.imagePath) {
await this.loadBackground(opts.imagePath);
await this.loadAndSetBackground(opts.imagePath);
} else {
this.gl?.setBackgroundImage(null);
}
Expand Down