Support WASM asset loading for MediaPipe Task Web

PiperOrigin-RevId: 547882566

mediapipe/tasks/web/core/task_runner.ts

@@ -25,9 +25,6 @@ import {SupportModelResourcesGraphService} from '../../../web/graph_runner/regis
 
 import {WasmFileset} from './wasm_fileset';
 
-// None of the MP Tasks ship bundle assets.
-const NO_ASSETS = undefined;
-
 // Internal stream names for temporarily keeping memory alive, then freeing it.
 const FREE_MEMORY_STREAM = 'free_memory';
 const UNUSED_STREAM_SUFFIX = '_unused_out';
@@ -61,7 +58,8 @@ export async function createTaskRunner<T extends TaskRunner>(
   };
 
   const instance = await createMediaPipeLib(
-      type, fileset.wasmLoaderPath, NO_ASSETS, canvas, fileLocator);
+      type, fileset.wasmLoaderPath, fileset.assetLoaderPath, canvas,
+      fileLocator);
   await instance.setOptions(options);
   return instance;
 }
@@ -96,13 +94,19 @@ export abstract class TaskRunner {
   abstract setOptions(options: TaskRunnerOptions): Promise<void>;
 
   /**
-   * Applies the current set of options, including any base options that have
-   * not been processed by the task implementation. The options are applied
-   * synchronously unless a `modelAssetPath` is provided. This ensures that
-   * for most use cases options are applied directly and immediately affect
+   * Applies the current set of options, including optionally any base options
+   * that have not been processed by the task implementation. The options are
+   * applied synchronously unless a `modelAssetPath` is provided. This ensures
+   * that for most use cases options are applied directly and immediately affect
    * the next inference.
+   *
+   * @param options The options for the task.
+   * @param loadTfliteModel Whether to load the model specified in
+   *     `options.baseOptions`.
    */
-  protected applyOptions(options: TaskRunnerOptions): Promise<void> {
+  protected applyOptions(options: TaskRunnerOptions, loadTfliteModel = true):
+      Promise<void> {
+    if (loadTfliteModel) {
       const baseOptions: BaseOptions = options.baseOptions || {};
 
       // Validate that exactly one model is configured
@@ -133,8 +137,8 @@ export abstract class TaskRunner {
             })
             .then(buffer => {
               try {
-              // Try to delete file as we cannot overwite an existing file using
-              // our current API.
+                // Try to delete file as we cannot overwite an existing file
+                // using our current API.
                 this.graphRunner.wasmModule.FS_unlink('/model.dat');
               } catch {
               }
@@ -149,13 +153,15 @@ export abstract class TaskRunner {
               this.onGraphRefreshed();
             });
       } else {
-      // Apply the setting synchronously.
         this.setExternalFile(baseOptions.modelAssetBuffer);
+      }
+    }
+
+    // If there is no model to download, we can apply the setting synchronously.
     this.refreshGraph();
     this.onGraphRefreshed();
     return Promise.resolve();
   }
-  }
 
   /** Appliest the current options to the MediaPipe graph. */
   protected abstract refreshGraph(): void;

mediapipe/tasks/web/core/wasm_fileset.d.ts

@@ -22,4 +22,6 @@ export declare interface WasmFileset {
   wasmLoaderPath: string;
   /** The path to the Wasm binary. */
   wasmBinaryPath: string;
+  /** The optional path to the asset loader script. */
+  assetLoaderPath?: string;
 }

mediapipe/tasks/web/vision/core/vision_task_runner.ts

@@ -70,7 +70,8 @@ export abstract class VisionTaskRunner extends TaskRunner {
    * @param imageStreamName the name of the input image stream.
    * @param normRectStreamName the name of the input normalized rect image
    *     stream used to provide (mandatory) rotation and (optional)
-   *     region-of-interest.
+   *     region-of-interest. `null` if the graph does not support normalized
+   *     rects.
    * @param roiAllowed Whether this task supports Region-Of-Interest
    *     pre-processing
    *
@@ -79,13 +80,20 @@ export abstract class VisionTaskRunner extends TaskRunner {
   constructor(
       protected override readonly graphRunner: VisionGraphRunner,
       private readonly imageStreamName: string,
-      private readonly normRectStreamName: string,
+      private readonly normRectStreamName: string|null,
       private readonly roiAllowed: boolean) {
     super(graphRunner);
   }
 
-  /** Configures the shared options of a vision task. */
-  override applyOptions(options: VisionTaskOptions): Promise<void> {
+  /**
+   * Configures the shared options of a vision task.
+   *
+   * @param options The options for the task.
+   * @param loadTfliteModel Whether to load the model specified in
+   *     `options.baseOptions`.
+   */
+  override applyOptions(options: VisionTaskOptions, loadTfliteModel = true):
+      Promise<void> {
     if ('runningMode' in options) {
       const useStreamMode =
           !!options.runningMode && options.runningMode !== 'IMAGE';
@@ -98,7 +106,7 @@ export abstract class VisionTaskRunner extends TaskRunner {
       }
     }
 
-    return super.applyOptions(options);
+    return super.applyOptions(options, loadTfliteModel);
   }
 
   /** Sends a single image to the graph and awaits results. */
@@ -209,11 +217,13 @@ export abstract class VisionTaskRunner extends TaskRunner {
       imageSource: ImageSource,
       imageProcessingOptions: ImageProcessingOptions|undefined,
       timestamp: number): void {
+    if (this.normRectStreamName) {
       const normalizedRect =
           this.convertToNormalizedRect(imageSource, imageProcessingOptions);
       this.graphRunner.addProtoToStream(
           normalizedRect.serializeBinary(), 'mediapipe.NormalizedRect',
           this.normRectStreamName, timestamp);
+    }
     this.graphRunner.addGpuBufferAsImageToStream(
         imageSource, this.imageStreamName, timestamp ?? performance.now());
     this.finishProcessing();