Revert "Update Virtual Background Model (#9867)" (#10247)

This reverts commit 9b6b335c60.

react/features/stream-effects/virtual-background/JitsiStreamBackgroundEffect.js

@@ -166,10 +166,14 @@ export default class JitsiStreamBackgroundEffect {
         const outputMemoryOffset = this._model._getOutputMemoryOffset() / 4;
 
         for (let i = 0; i < this._segmentationPixelCount; i++) {
-            const person = this._model.HEAPF32[outputMemoryOffset + i];
-            
+            const background = this._model.HEAPF32[outputMemoryOffset + (i * 2)];
+            const person = this._model.HEAPF32[outputMemoryOffset + (i * 2) + 1];
+            const shift = Math.max(background, person);
+            const backgroundExp = Math.exp(background - shift);
+            const personExp = Math.exp(person - shift);
+
             // Sets only the alpha component of each pixel.
-            this._segmentationMask.data[(i * 4) + 3] = (255 * person);
+            this._segmentationMask.data[(i * 4) + 3] = (255 * personExp) / (backgroundExp + personExp);
         }
         this._segmentationMaskCtx.putImageData(this._segmentationMask, 0, 0);
     }

react/features/stream-effects/virtual-background/index.js

@@ -8,8 +8,8 @@ import JitsiStreamBackgroundEffect from './JitsiStreamBackgroundEffect';
 import createTFLiteModule from './vendor/tflite/tflite';
 import createTFLiteSIMDModule from './vendor/tflite/tflite-simd';
 const models = {
-    model_landscape: 'libs/selfie_segmentation_landscape.tflite'
-    
+    model96: 'libs/segm_lite_v681.tflite',
+    model144: 'libs/segm_full_v679.tflite'
 };
 
 let tflite;
@@ -17,7 +17,11 @@ let wasmCheck;
 let isWasmDisabled = false;
 
 const segmentationDimensions = {
-    model_landscape: {
+    model96: {
+        height: 96,
+        width: 160
+    },
+    model144: {
         height: 144,
         width: 256
     }
@@ -72,7 +76,7 @@ export async function createVirtualBackgroundEffect(virtualBackground: Object, d
     }
 
     const modelBufferOffset = tflite._getModelBufferMemoryOffset();
-    const modelResponse = await fetch(models.model_landscape); 
+    const modelResponse = await fetch(wasmCheck.feature.simd ? models.model144 : models.model96);
 
     if (!modelResponse.ok) {
         throw new Error('Failed to download tflite model!');
@@ -85,12 +89,9 @@ export async function createVirtualBackgroundEffect(virtualBackground: Object, d
     tflite._loadModel(model.byteLength);
 
     const options = {
-        ...segmentationDimensions.model_landscape,
+        ...wasmCheck.feature.simd ? segmentationDimensions.model144 : segmentationDimensions.model96,
         virtualBackground
-    }; 
-
-
-    
+    };
 
     return new JitsiStreamBackgroundEffect(tflite, options);
 }