docs: properly document createStream

README.md

@@ -191,3 +191,30 @@ const player = new Player(client, {
     }
 });
 ```
+
+### Custom stream Engine
+
+Discord Player by default uses **[node-ytdl-core](https://github.com/fent/node-ytdl-core)** for youtube and some other extractors for other sources.
+If you need to modify this behavior without touching extractors, you need to use `createStream` functionality of discord player.
+Here's an example on how you can use **[play-dl](https://npmjs.com/package/play-dl)** to download youtube streams instead of using ytdl-core.
+
+```js
+const playdl = require("play-dl");
+
+// other code
+
+const queue = player.createQueue(...);
+if (!queue.createStream) {
+    queue.createStream = async (track, source, _queue) => {
+        // only trap youtube source
+        if (source === "youtube") {
+            // track here would be youtube track
+            return (await playdl.stream(track.url)).stream;
+            // we must return readable stream or void (returning void means telling discord-player to look for default extractor)
+        }
+    };
+}
+```
+
+`<Queue>.createStream` is called before actually downloading the stream. It is a different concept from extractors, where you are **just** downloading
+streams. `source` here will be a video source. Streams from `createStream` are then piped to `FFmpeg` and finally sent to Discord voice servers.

docs/extractors/create_stream.md

@@ -2,14 +2,47 @@
 
 This is a checkpoint where discord-player calls `createStream` before downloading stream.
 
-# Example
+### Custom stream Engine
+
+Discord Player by default uses **[node-ytdl-core](https://github.com/fent/node-ytdl-core)** for youtube and some other extractors for other sources.
+If you need to modify this behavior without touching extractors, you need to use `createStream` functionality of discord player.
+Here's an example on how you can use **[play-dl](https://npmjs.com/package/play-dl)** to download youtube streams instead of using ytdl-core.
 
 ```js
-const dl = require("my-cool-vid-downloader");
+const playdl = require("play-dl");
 
-// after creating queue, attach this handler, that's it!
+// other code
-queue.createStream = (track, source, queue) => {
+
-    const stream = dl(track.url);
+const queue = player.createQueue(...);
-    return stream;
+if (!queue.createStream) {
+    queue.createStream = async (track, source, _queue) => {
+        // only trap youtube source
+        if (source === "youtube") {
+            // track here would be youtube track
+            return (await playdl.stream(track.url)).stream;
+            // we must return readable stream or void (returning void means telling discord-player to look for default extractor)
+        }
     };
+}
 ```
+
+`<Queue>.createStream` is called before actually downloading the stream. It is a different concept from extractors, where you are **just** downloading
+streams. `source` here will be a video source. Streams from `createStream` are then piped to `FFmpeg` and finally sent to Discord voice servers.
+
+# FAQ
+## How can I remove this?
+
+> If you already made this change and want to switch to default mode in runtime,
+> you can set `queue.createStream` to `null` which will make `discord-player` use default config.
+
+## Which stream format should I return?
+
+> It's not necessary to return opus format or whatever, since every streams have to be converted to s16le, due to inline volume.
+
+## Can I use ytdl-core-discord?
+
+> Yes, you can.
+
+## Can I use this for other sources, like soundcloud?
+
+> Absolutely.

src/Structures/Queue.ts

@@ -645,7 +645,7 @@ class Queue<T = unknown> {
             if (!link) return void this.play(this.tracks.shift(), { immediate: true });
 
             if (customDownloader) {
-                stream = (await this.createStream(track, link, this)) ?? null;
+                stream = (await this.createStream(track, "youtube", this)) ?? null;
                 if (stream)
                     stream = ytdl
                         .arbitraryStream(stream, {