estimate bandwidth

1 files changed, 42 insertions, 0 deletions

diff --git a/web/script/player/download.ts b/web/script/player/download.ts
new file mode 100644
index 0000000..63085b8
--- /dev/null
+++ b/web/script/player/download.ts
@@ -0,0 +1,42 @@
+import { OVar } from "../jshelper/mod.ts";
+
+interface Measurement { time: number, duration: number, size: number }
+export class SegmentDownloader {
+    private measurements: Measurement[] = []
+
+    public bandwidth = new OVar(Infinity)
+
+    constructor() { }
+
+    async download(url: string): Promise<ArrayBuffer> {
+        const dl_start = performance.now();
+        const res = await fetch(url)
+        const dl_header = performance.now();
+        if (!res.ok) throw new Error("aaaaa");
+        const buf = await res.arrayBuffer()
+        const dl_body = performance.now();
+
+        if (buf.byteLength > 500 * 1000) {
+            const m = {
+                time: dl_start,
+                duration: (dl_body - dl_header) / 1000,
+                size: buf.byteLength
+            }
+            console.log(m);
+            this.measurements.push(m)
+            this.update_bandwidth()
+        }
+        return buf;
+    }
+
+    update_bandwidth() {
+        while (this.measurements.length > 32)
+            this.measurements.splice(0, 1)
+        const total_size = this.measurements.reduce((a, v) => v.size + a, 0)
+        const total_duration = this.measurements.reduce((a, v) => v.duration + a, 0)
+        const average = total_size / total_duration
+        console.log(total_size, average, this.measurements);
+
+        this.bandwidth.value = average
+    }
+}