Add performance comparison

apps/vanilla-app/public/transcode-mt.html

@@ -31,7 +31,9 @@
         const { name } = files[0];
         await ffmpeg.writeFile(name, await fetchFile(files[0]));
         message.innerHTML = 'Start transcoding';
+        console.time('exec');
         await ffmpeg.exec(['-i', name,  'output.mp4']);
+        console.timeEnd('exec');
         message.innerHTML = 'Complete transcoding';
         const data = await ffmpeg.readFile('output.mp4');
 

apps/vanilla-app/public/transcode.html

@@ -31,7 +31,9 @@
         const { name } = files[0];
         await ffmpeg.writeFile(name, await fetchFile(files[0]));
         message.innerHTML = 'Start transcoding';
+        console.time('exec');
         await ffmpeg.exec(['-i', name,  'output.mp4']);
+        console.timeEnd('exec');
         message.innerHTML = 'Complete transcoding';
         const data = await ffmpeg.readFile('output.mp4');
 

apps/website/docs/performance.md

@@ -0,0 +1,35 @@
+# Performance
+
+ffmpeg.wasm uses transpiled FFmpeg C source code to WebAssembly code, it is for
+certain that ffmpeg.wasm won't perform as good as FFmpeg as it is not fully
+optimized at the moment. (Even in ffmpeg.wasm multithread version). In this
+section we provide a short comparison, so that you can make decision based on your
+needs:
+
+## Environment
+
+- CPU: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
+- Memory: 15.6 GiB of RAM
+- OS: Manjaro Linux 6.1.44-1-MANJARO (64-bit)
+- Browser: Google Chrome Version 116.0.5845.96 (Official Build) (64-bit)
+- FFmpeg: n5.1.2
+
+## Comparison
+
+Setup:
+
+- Each command is executed 5 times.
+- Only `ffmpeg.exec()` time is measured.
+- Candidates
+  - FFmpeg: [native FFmpeg](https://hub.docker.com/r/linuxserver/ffmpeg),
+      considered as baseline.
+  - core: ffmpeg.wasm single thread version.
+  - core-mt: ffmpeg.wasm multi thread version.
+
+### $ ffmpeg -i [input.webm](https://test-videos.co.uk/vids/bigbuckbunny/webm/vp8/720/Big_Buck_Bunny_720_10s_1MB.webm) output.mp4
+
+|  #  | FFmpeg | core v0.12.2 | core-mt v0.12.2 |
+| --- | ------ | ------------ | --------------- |
+| Avg | 5.2 sec | 128.8 sec (0.04x) | 60.4 sec (0.08x) |
+| Max | 5.3 sec | 130.7 sec | 63.9 sec |
+| Min | 5.1 sec | 126.6 sec | 59 sec |

apps/website/sidebars.js

@@ -28,6 +28,7 @@ const sidebars = {
         "getting-started/examples",
       ],
     },
+    "performance",
     "migration",
     "faq",
     {