Further approach for measurement and estimation of throughput calculation in LL CTE streaming

build/helpers/LLsegment.js

@@ -0,0 +1,100 @@
+const fs = require("fs");
+const path = require("path");
+
+const segmentData = fs.readFileSync(path.join(__dirname, 'data', 'chunk', 'chunk-stream_0-00001.m4s'));
+const segmentInfo = fs.readFileSync(path.join(__dirname, 'data', 'chunk', 'chunk-stream_0-00001.json')).toString();
+
+function sendChunks(res, segmentInfoData, param, interval, previousTs, chunkDistances) {
+    let chunksInBurst = 0;
+    if (param.chunksAvailableAtReqTime) {
+        chunksInBurst = param.chunksAvailableAtReqTime;
+        param.chunksAvailableAtReqTime = 0;
+    } else {
+        chunksInBurst = param.chunkCount;
+    }
+
+    for (let index = 0; index < chunksInBurst; index++) {
+        let mdatFound = false;
+        let chunkSize = 0;
+        while (!mdatFound && segmentInfoData.length) {
+            let box = segmentInfoData.shift();
+            mdatFound = box.name === 'mdat';
+            chunkSize += box.size;
+        }
+        if (chunkSize) {
+            res.write(segmentData.slice(param.pos, param.pos + chunkSize));
+            param.pos = param.pos + chunkSize;
+        }
+    }
+    if (!segmentInfoData.length) {
+        if (chunkDistances && chunkDistances.length) {
+            // console.log('all sent with average chunk (burst) distance', chunkDistances.reduce((prev, curr) => prev + curr, 0) / chunkDistances.length)
+        }
+        return res.end();
+    }
+
+    let processingDuration = 0;
+    const chunkDistance = Date.now() - previousTs;
+    // console.log('ms since last call', chunkDistance)
+
+    if (chunkDistance > interval) {
+        chunkDistances.push(chunkDistance)
+        processingDuration = chunkDistance - interval;
+    }
+    if (interval - processingDuration > 0) {
+        setTimeout((previousTs) => {
+            sendChunks(res, segmentInfoData, param, interval, previousTs, chunkDistances);
+        }, interval - processingDuration, Date.now()); // minus processing duration on producer side
+    }
+}
+
+function streamWithPattern(res, interval, chunkCount, chunksAvailableAtReqTime) {
+    const segmentInfoData = JSON.parse(segmentInfo);
+
+    res.statusCode = 200;
+
+    const param = {
+        chunkCount,
+        pos: 0,
+        chunksAvailableAtReqTime
+    }
+
+    sendChunks(res, segmentInfoData, param, interval, Date.now(), []);
+}
+
+
+module.exports = function (req, res) {
+    switch (req.url) {
+        case '/ll/pattern0':
+            streamWithPattern(res, 0, 0, 60);
+            break;
+        case '/ll/pattern1':
+            streamWithPattern(res, 33, 1, 0);
+            break;
+        case '/ll/pattern2':
+            streamWithPattern(res, 133, 4, 0);
+            break;
+        case '/ll/pattern3':
+            streamWithPattern(res, 333, 10, 0);
+            break;
+        case '/ll/pattern4':
+            streamWithPattern(res, 1000, 30, 0);
+            break;
+        case '/ll/pattern5':
+            streamWithPattern(res, 33, 1, 30);
+            break;
+        case '/ll/pattern6':
+            streamWithPattern(res, 133, 4, 30);
+            break;
+        case '/ll/pattern7':
+            streamWithPattern(res, 333, 10, 30);
+            break;
+        case '/ll/pattern8':
+            streamWithPattern(res, 1000, 30, 30);
+            break;
+        default:
+            console.log('unknown', req.url);
+            res.statusCode = 404;
+            return res.end();
+    }
+};