API名称： wx.createWorker 开启useExperimentalWorker

手机信息： iphone13pro iOS 17.1.1

微信版本：8.0.44

基础库： 3.2.1

现象：在使用xr-frame时，获取了相机的yBuffer，uvBuffer后，传递到worker进行压缩，压缩完成后返回主线程发送请求。 在android真机上正常，在iOS真机上非常卡顿。将useExperimentalWorker关闭恢复正常。

// index
function createNewWorker() {
  const worker = wx.createWorker('workers/index.js', {
    useExperimentalWorker: true
  })
  return worker;
}

this.worker = createNewWorker();

// 监听worker被系统回收事件
this.worker.onProcessKilled(() => {
  // 重新创建一个worker
  this.worker = createNewWorker()
})

const ArRawData = this.arSystem.getARRawData();
const uvBuffer = ArRawData.uvBuffer;
const yBuffer = ArRawData.yBuffer;
const width = ArRawData.width;
const height = ArRawData.height;
const scaleFactor = wx.getSystemInfoSync().pixelRatio;

this.worker.postMessage({
  type: 'yuv',
  data: {
    width,
    height,
    scaleFactor,
    yBuffer,
    uvBuffer,
  }
})

// worker
import {
  encode
} from 'base64-arraybuffer/index';

function downscaleYUV(yData, uvData, originalWidth, originalHeight, scaleFactor) {
  const newWidth = Math.floor(originalWidth / scaleFactor);
  const newHeight = Math.floor(originalHeight / scaleFactor);

  const newYData = new Uint8Array(newWidth * newHeight);
  const newUVData = new Uint8Array(newWidth / 2 * newHeight / 2 * 2);

  for (let y = 0; y < newHeight; y++) {
    for (let x = 0; x < newWidth; x++) {
      const originalX = x * scaleFactor;
      const originalY = y * scaleFactor;

      const newYIndex = y * newWidth + x;
      const originalYIndex = originalY * originalWidth + originalX;

      newYData[newYIndex] = yData[originalYIndex];

      // For UV channel
      const originalUVIndex = Math.floor(originalY / 2) * Math.floor(originalWidth / 2) + Math.floor(originalX / 2);
      const newUVIndex = Math.floor(y / 2) * Math.floor(newWidth / 2) + Math.floor(x / 2);

      newUVData[newUVIndex * 2] = uvData[originalUVIndex * 2];
      newUVData[newUVIndex * 2 + 1] = uvData[originalUVIndex * 2 + 1];
    }
  }

  return {
    newYData,
    newUVData,
    newWidth,
    newHeight
  };
}

worker.onMessage(function (res) {
  switch(res.type) {
    case 'yuv': {
      const { width, height, yBuffer, uvBuffer, scaleFactor } = res.data;
      const { newYData, newUVData, newWidth, newHeight } = downscaleYUV(
        new Uint8Array(yBuffer),
        new Uint8Array(uvBuffer),
        width,
        height,
        scaleFactor
      );

      worker.postMessage({
        type: 'yuv_result',
        data: {
          scaleFactor,
          yBuffer: encode(newYData),
          uvBuffer: encode(newUVData),
        }
      })
    }
  }
})