diff --git a/codecs/avif/dec/avif_dec.d.ts b/codecs/avif/dec/avif_dec.d.ts
index ff52bcff..b2e56d3b 100644
--- a/codecs/avif/dec/avif_dec.d.ts
+++ b/codecs/avif/dec/avif_dec.d.ts
@@ -1,6 +1,7 @@
-interface AVIFModule extends EmscriptenWasm.Module {
+export interface AVIFModule extends EmscriptenWasm.Module {
   decode(data: BufferSource): ImageData | null;
 }
 
-export default function(opts: EmscriptenWasm.ModuleOpts): AVIFModule;
+declare var moduleFactory: EmscriptenWasm.ModuleFactory<AVIFModule>;
 
+export default moduleFactory;
diff --git a/codecs/avif/enc/avif_enc.d.ts b/codecs/avif/enc/avif_enc.d.ts
index c00e18e7..2f1436fe 100644
--- a/codecs/avif/enc/avif_enc.d.ts
+++ b/codecs/avif/enc/avif_enc.d.ts
@@ -1,7 +1,14 @@
-import { EncodeOptions } from '../../../src/codecs/avif/encoder-meta';
+import { EncodeOptions } from 'image-worker/avifEncode';
 
-interface AVIFModule extends EmscriptenWasm.Module {
-  encode(data: BufferSource, width: number, height: number, options: EncodeOptions): Uint8Array | null;
+export interface AVIFModule extends EmscriptenWasm.Module {
+  encode(
+    data: BufferSource,
+    width: number,
+    height: number,
+    options: EncodeOptions,
+  ): Uint8Array | null;
 }
 
-export default function(opts: EmscriptenWasm.ModuleOpts): AVIFModule;
+declare var moduleFactory: EmscriptenWasm.ModuleFactory<AVIFModule>;
+
+export default moduleFactory;
diff --git a/src/image-worker/avifDecode/index.ts b/src/image-worker/avifDecode/index.ts
new file mode 100644
index 00000000..cdf04b11
--- /dev/null
+++ b/src/image-worker/avifDecode/index.ts
@@ -0,0 +1,28 @@
+/**
+ * Copyright 2020 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import avifDecoder, { AVIFModule } from 'codecs/avif/dec/avif_dec';
+import wasmUrl from 'url:codecs/avif/dec/avif_dec.wasm';
+import { initEmscriptenModule } from '../util';
+
+let emscriptenModule: Promise<AVIFModule>;
+
+export default async function decode(data: ArrayBuffer): Promise<ImageData> {
+  if (!emscriptenModule) {
+    emscriptenModule = initEmscriptenModule(avifDecoder, wasmUrl);
+  }
+
+  const module = await emscriptenModule;
+  const result = module.decode(data);
+  if (!result) throw new Error('Decoding error');
+  return result;
+}
diff --git a/src/image-worker/avifEncode/index.ts b/src/image-worker/avifEncode/index.ts
new file mode 100644
index 00000000..66c707a1
--- /dev/null
+++ b/src/image-worker/avifEncode/index.ts
@@ -0,0 +1,45 @@
+/**
+ * Copyright 2020 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import avifEncoder, { AVIFModule } from 'codecs/avif/enc/avif_enc';
+import wasmUrl from 'url:codecs/avif/enc/avif_enc.wasm';
+import { initEmscriptenModule } from '../util';
+
+export interface EncodeOptions {
+  minQuantizer: number;
+  maxQuantizer: number;
+  minQuantizerAlpha: number;
+  maxQuantizerAlpha: number;
+  tileRowsLog2: number;
+  tileColsLog2: number;
+  speed: number;
+  subsample: number;
+}
+
+let emscriptenModule: Promise<AVIFModule>;
+
+export default async function encode(
+  data: ImageData,
+  options: EncodeOptions,
+): Promise<ArrayBuffer> {
+  if (!emscriptenModule) {
+    emscriptenModule = initEmscriptenModule(avifEncoder, wasmUrl);
+  }
+
+  const module = await emscriptenModule;
+  const result = module.encode(data.data, data.width, data.height, options);
+
+  if (!result) throw new Error('Encoding error');
+
+  // wasm can’t run on SharedArrayBuffers, so we hard-cast to ArrayBuffer.
+  return result.buffer as ArrayBuffer;
+}
diff --git a/src/codecs/avif/decoder-meta.ts b/src_old/codecs/avif/decoder-meta.ts
similarity index 100%
rename from src/codecs/avif/decoder-meta.ts
rename to src_old/codecs/avif/decoder-meta.ts
diff --git a/src/codecs/avif/decoder.ts b/src_old/codecs/avif/decoder.ts
similarity index 83%
rename from src/codecs/avif/decoder.ts
rename to src_old/codecs/avif/decoder.ts
index 0dc55b37..234d5268 100644
--- a/src/codecs/avif/decoder.ts
+++ b/src_old/codecs/avif/decoder.ts
@@ -5,7 +5,8 @@ import { initEmscriptenModule } from '../util';
 let emscriptenModule: Promise<AVIFModule>;
 
 export async function decode(data: ArrayBuffer): Promise<ImageData> {
-  if (!emscriptenModule) emscriptenModule = initEmscriptenModule(avif_dec, wasmUrl);
+  if (!emscriptenModule)
+    emscriptenModule = initEmscriptenModule(avif_dec, wasmUrl);
 
   const module = await emscriptenModule;
   const result = module.decode(data);
diff --git a/src/codecs/avif/encoder-meta.ts b/src_old/codecs/avif/encoder-meta.ts
similarity index 87%
rename from src/codecs/avif/encoder-meta.ts
rename to src_old/codecs/avif/encoder-meta.ts
index c051064e..7df64b40 100644
--- a/src/codecs/avif/encoder-meta.ts
+++ b/src_old/codecs/avif/encoder-meta.ts
@@ -24,4 +24,7 @@ export const defaultOptions: EncodeOptions = {
   subsample: 1,
 };
 
-export interface EncoderState { type: typeof type; options: EncodeOptions; }
+export interface EncoderState {
+  type: typeof type;
+  options: EncodeOptions;
+}
diff --git a/src/codecs/avif/encoder.ts b/src_old/codecs/avif/encoder.ts
similarity index 75%
rename from src/codecs/avif/encoder.ts
rename to src_old/codecs/avif/encoder.ts
index 50b33ab1..8c4088d5 100644
--- a/src/codecs/avif/encoder.ts
+++ b/src_old/codecs/avif/encoder.ts
@@ -5,8 +5,12 @@ import { initEmscriptenModule } from '../util';
 
 let emscriptenModule: Promise<AVIFModule>;
 
-export async function encode(data: ImageData, options: EncodeOptions): Promise<ArrayBuffer> {
-  if (!emscriptenModule) emscriptenModule = initEmscriptenModule(avif_enc, wasmUrl);
+export async function encode(
+  data: ImageData,
+  options: EncodeOptions,
+): Promise<ArrayBuffer> {
+  if (!emscriptenModule)
+    emscriptenModule = initEmscriptenModule(avif_enc, wasmUrl);
 
   const module = await emscriptenModule;
   const result = module.encode(data.data, data.width, data.height, options);
diff --git a/src/codecs/avif/options.tsx b/src_old/codecs/avif/options.tsx
similarity index 79%
rename from src/codecs/avif/options.tsx
rename to src_old/codecs/avif/options.tsx
index ac957d3c..dd85f60c 100644
--- a/src/codecs/avif/options.tsx
+++ b/src_old/codecs/avif/options.tsx
@@ -34,18 +34,28 @@ const maxQuant = 63;
 const maxSpeed = 10;
 
 export default class AVIFEncoderOptions extends Component<Props, State> {
-  static getDerivedStateFromProps(props: Props, state: State): Partial<State> | undefined {
+  static getDerivedStateFromProps(
+    props: Props,
+    state: State,
+  ): Partial<State> | undefined {
     if (state.options && shallowEqual(state.options, props.options)) return;
     const { options } = props;
 
     const lossless = options.maxQuantizer === 0 && options.minQuantizer === 0;
-    const minQuantizerValue = lossless ? defaultOptions.minQuantizer : options.minQuantizer;
-    const maxQuantizerValue = lossless ? defaultOptions.maxQuantizer : options.maxQuantizer;
-    const losslessAlpha = options.maxQuantizerAlpha === 0 && options.minQuantizerAlpha === 0;
-    const minQuantizerAlphaValue = losslessAlpha ?
-      defaultOptions.minQuantizerAlpha : options.minQuantizerAlpha;
-    const maxQuantizerAlphaValue = losslessAlpha ?
-      defaultOptions.maxQuantizerAlpha : options.maxQuantizerAlpha;
+    const minQuantizerValue = lossless
+      ? defaultOptions.minQuantizer
+      : options.minQuantizer;
+    const maxQuantizerValue = lossless
+      ? defaultOptions.maxQuantizer
+      : options.maxQuantizer;
+    const losslessAlpha =
+      options.maxQuantizerAlpha === 0 && options.minQuantizerAlpha === 0;
+    const minQuantizerAlphaValue = losslessAlpha
+      ? defaultOptions.minQuantizerAlpha
+      : options.minQuantizerAlpha;
+    const maxQuantizerAlphaValue = losslessAlpha
+      ? defaultOptions.maxQuantizerAlpha
+      : options.maxQuantizerAlpha;
 
     // Create default form state from options
     return {
@@ -54,12 +64,16 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
       losslessAlpha,
       maxQuality: maxQuant - minQuantizerValue,
       minQuality: maxQuant - maxQuantizerValue,
-      separateAlpha: options.maxQuantizer !== options.maxQuantizerAlpha ||
+      separateAlpha:
+        options.maxQuantizer !== options.maxQuantizerAlpha ||
         options.minQuantizer !== options.minQuantizerAlpha,
       maxAlphaQuality: maxQuant - minQuantizerAlphaValue,
       minAlphaQuality: maxQuant - maxQuantizerAlphaValue,
       grayscale: options.subsample === 0,
-      subsample: options.subsample === 0 || lossless ? defaultOptions.subsample : options.subsample,
+      subsample:
+        options.subsample === 0 || lossless
+          ? defaultOptions.subsample
+          : options.subsample,
       tileRows: options.tileRowsLog2,
       tileCols: options.tileColsLog2,
       effort: maxSpeed - options.speed,
@@ -78,9 +92,12 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
     if (!this._inputChangeCallbacks.has(prop)) {
       this._inputChangeCallbacks.set(prop, (event: Event) => {
         const formEl = event.target as HTMLInputElement | HTMLSelectElement;
-        const newVal = type === 'boolean' ?
-          'checked' in formEl ? formEl.checked : !!formEl.value :
-          Number(formEl.value);
+        const newVal =
+          type === 'boolean'
+            ? 'checked' in formEl
+              ? formEl.checked
+              : !!formEl.value
+            : Number(formEl.value);
 
         const newState: Partial<State> = {
           [prop]: newVal,
@@ -115,20 +132,32 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
           ...newState,
         };
 
-        const maxQuantizer = optionState.lossless ? 0 : (maxQuant - optionState.minQuality);
-        const minQuantizer = optionState.lossless ? 0 : (maxQuant - optionState.maxQuality);
+        const maxQuantizer = optionState.lossless
+          ? 0
+          : maxQuant - optionState.minQuality;
+        const minQuantizer = optionState.lossless
+          ? 0
+          : maxQuant - optionState.maxQuality;
 
         const newOptions: EncodeOptions = {
           maxQuantizer,
           minQuantizer,
-          maxQuantizerAlpha: optionState.separateAlpha ?
-            (optionState.losslessAlpha ? 0 : (maxQuant - optionState.minAlphaQuality)) :
-            maxQuantizer,
-          minQuantizerAlpha: optionState.separateAlpha ?
-            (optionState.losslessAlpha ? 0 : (maxQuant - optionState.maxAlphaQuality)) :
-            minQuantizer,
+          maxQuantizerAlpha: optionState.separateAlpha
+            ? optionState.losslessAlpha
+              ? 0
+              : maxQuant - optionState.minAlphaQuality
+            : maxQuantizer,
+          minQuantizerAlpha: optionState.separateAlpha
+            ? optionState.losslessAlpha
+              ? 0
+              : maxQuant - optionState.maxAlphaQuality
+            : minQuantizer,
           // Always set to 4:4:4 if lossless
-          subsample: optionState.grayscale ? 0 : optionState.lossless ? 3 : optionState.subsample,
+          subsample: optionState.grayscale
+            ? 0
+            : optionState.lossless
+            ? 3
+            : optionState.subsample,
           tileColsLog2: optionState.tileCols,
           tileRowsLog2: optionState.tileRows,
           speed: maxSpeed - optionState.effort,
@@ -147,13 +176,24 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
     }
 
     return this._inputChangeCallbacks.get(prop)!;
-  }
+  };
 
   render(
     _: Props,
     {
-      effort, grayscale, lossless, losslessAlpha, maxAlphaQuality, maxQuality, minAlphaQuality,
-      minQuality, separateAlpha, showAdvanced, subsample, tileCols, tileRows,
+      effort,
+      grayscale,
+      lossless,
+      losslessAlpha,
+      maxAlphaQuality,
+      maxQuality,
+      minAlphaQuality,
+      minQuality,
+      separateAlpha,
+      showAdvanced,
+      subsample,
+      tileCols,
+      tileRows,
     }: State,
   ) {
     return (
@@ -199,7 +239,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
           Separate alpha quality
         </label>
         <Expander>
-        {separateAlpha && (
+          {separateAlpha && (
             <div>
               <label class={style.optionInputFirst}>
                 <Checkbox
@@ -209,7 +249,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
                 Lossless alpha
               </label>
               <Expander>
-                {!losslessAlpha &&
+                {!losslessAlpha && (
                   <div>
                     <div class={style.optionOneCell}>
                       <Range
@@ -232,7 +272,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
                       </Range>
                     </div>
                   </div>
-                }
+                )}
               </Expander>
             </div>
           )}
@@ -245,7 +285,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
           Show advanced settings
         </label>
         <Expander>
-          {showAdvanced &&
+          {showAdvanced && (
             <div>
               {/*<label class={style.optionInputFirst}>
                 <Checkbox
@@ -256,7 +296,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
                 Grayscale
               </label>*/}
               <Expander>
-                {!grayscale && !lossless &&
+                {!grayscale && !lossless && (
                   <label class={style.optionTextFirst}>
                     Subsample chroma:
                     <Select
@@ -269,7 +309,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
                       <option value="3">4:4:4</option>
                     </Select>
                   </label>
-                }
+                )}
               </Expander>
               <div class={style.optionOneCell}>
                 <Range
@@ -292,7 +332,7 @@ export default class AVIFEncoderOptions extends Component<Props, State> {
                 </Range>
               </div>
             </div>
-          }
+          )}
         </Expander>
         <div class={style.optionOneCell}>
           <Range