use worker on remote camera to decode jpg image

RemoteCamera/js/decoder.js

@@ -0,0 +1,42 @@
+decode = (arr) =>
+{
+    if(!JpegImage)
+    {
+        console.error("libjpeg is not available");
+        return;
+    }
+    let raw = new Uint8Array(arr);
+    let jpeg = new JpegImage();
+    jpeg.parse(raw);
+    let data = jpeg.getData(jpeg.width, jpeg.height);
+    let msg = {
+        w: jpeg.width,
+        h: jpeg.height,
+        pixels: undefined
+    }
+    msg.pixels = new Uint8Array(msg.w*msg.h*4);
+    for(let j = 0; j < msg.h; j++)
+    {
+        for(let i = 0; i < msg.w; i++)
+        {
+            let index = j*msg.w*4 + i*4;
+            msg.pixels[index] = data[j*msg.w*3 + i*3];
+            msg.pixels[index+1] = data[j*msg.w*3 + i*3 + 1];
+            msg.pixels[index+2] = data[j*msg.w*3 + i*3 + 2];
+            msg.pixels[index+3] = 255;
+        }
+    }
+    msg.pixels = msg.pixels.buffer;
+    postMessage(msg, [msg.pixels]);
+}
+
+onmessage = (e) => {
+    if(e.data.libjpeg)
+    {
+        importScripts(e.data.libjpeg);
+    }
+    else
+    {
+        decode(e.data);
+    }
+}