android-cloud-H5/static/screenIos/decoder.js

var isFinish = false;
var isSwitchSharpness = false;
var h264Queue = [];
var ret;

var maxWidth = 1080;
var maxHeight = 1920;
var globalYuvPtr = undefined;
var golbalYuvData; //全局，只分配一次
var renderCount = 0;
var curFrameWidth = undefined;
var curFrameHeight = undefined;

function doSomeInit() {
  var allocSize = maxWidth * maxHeight * 3;
  golbalYuvData = new Uint8Array(allocSize);
}
self.importScripts('ffmpeghelper.js');
self.importScripts('spsParser.js');

self.Module.onRuntimeInitialized = function () {
  isFinish = true;
  doSomeInit();
  ret = Module._openDecoder();

  if (!ret) {
    console.log('打开编码器成功');
  }
};

self.addEventListener(
  'message',
  function (e) {
    var msg = e.data;
    if (msg.type == 'rawData') {
      var buffer = e.data.data;

      if (buffer[0] !== 0xff) {
        // 音频解码
        var type = buffer[4] & 0x1f;
        if (type == 7) {
          let info = spsParser(buffer);

          if (curFrameWidth != undefined && curFrameHeight != undefined) {
            if (info.width != curFrameWidth || info.height != curFrameHeight) {
              // 分辨率发生改变，切换
              console.log('🚀 ~ file: decoder.js ~ line 44 ~ 分辨率发生改变');
              switchNewStream();
            }
          }

          curFrameWidth = info.width;
          curFrameHeight = info.height;
          h264Queue.push(buffer);
        } else {
          h264Queue.push(buffer);
        }
      }
    }
  },
  false,
);

function PrintfLog(str) {
  var curTime = new Date().getTime();
  var objData = {
    cmd: 0,
    data: str,
    time: curTime,
  };
  self.postMessage(objData);
}

function doRequestIFrame() {
  var objData = {
    cmd: 5,
  };
  self.postMessage(objData);
}

function decodeVideo() {
  if (h264Queue.length > 0 && isFinish) {
    decodeH264(h264Queue.shift());
  }
}

var timeFlag = setInterval(decodeVideo, 1);

//实现C 端到js yuv数据赋值, 并分配给opengl 渲染
/*yuvData, 存放yuv数据的数组
 * inputYuvPtr C++
 */
function dispatchYuvData(
  yuvData,
  inputYuvPtr,
  videoWidth,
  videoHeight,
  copyLen,
) {
  for (i = 0; i < copyLen; i++) {
    yuvData[i] = Module.HEAPU8[inputYuvPtr + i];
  }

  var curTime = new Date().getTime();
  var objData = {
    cmd: 1,
    data: yuvData,
    time: curTime,
    width: videoWidth,
    height: videoHeight,
  };
  self.postMessage(objData);
}

function decodeH264(data) {
  var frameWidth = 0;
  var frameHeight = 0;
  var inputPtr = Module._malloc(data.length); //输入数据

  for (var i = 0; i < data.length; i++) {
    Module.HEAPU8[inputPtr + i] = data[i]; //转换为堆数据
  }

  var allocSize = (maxWidth * maxHeight * 3) / 2;
  if (globalYuvPtr == undefined) {
    globalYuvPtr = Module._malloc(allocSize);
  }

  var ret = Module._feedData(inputPtr, data.length, globalYuvPtr);

  if (ret >= 0) {
    //解码成功才考虑渲染
    frameWidth = Module._getVideoWidth(); //拿到解码器宽、高
    frameHeight = Module._getVideoHeight();
    // console.log("🚀 ~ file: decoder.js ~ line 134 ~ decodeH264 ~ frameWidth", frameWidth,frameHeight)
    var copyLen = (frameWidth * frameHeight * 3) / 2; //只拷贝必须的长度

    if (renderCount > 1) {
      //第一帧因为画面时全绿色的不渲染
      dispatchYuvData(
        golbalYuvData,
        globalYuvPtr,
        frameWidth,
        frameHeight,
        copyLen,
      );
    } else {
      renderCount++;
    }
  }

  Module._free(inputPtr);
}

function switchNewStream() {
  closeDecoder();
  var ret = Module._openDecoder(); //再次开启解码器
  var timeFlag = setInterval(decodeVideo, 1);
  console.log('切换解码器成功');
}

function closeDecoder() {
  clearInterval(timeFlag); //关闭原有定时器
  Module._closeDecoder();
  renderCount = 0;

  if (globalYuvPtr != undefined) {
    Module._free(globalYuvPtr);
    globalYuvPtr = undefined;
  }
  console.log('此时buffer长度: %d', h264Queue.length);
  while (h264Queue.lengh > 0) {
    h264Queue.shift();
  }
}