Discord Plays Pokémon

This is a half-baked post I decided to publish because it was clear I wasn’t ever going to finish it. You can find the source code of this project on GitHub.

Idea

Twitch Plays Pokémon, but for Discord

Demo

Prior Art

Technical goals

  • Low-cost to deploy on AWS.
    • It therefore shouldn’t require many cores or a GPU
  • Require as few dependencies on the host as possible.
  • 100% automation, no manual action required.

Challenges

  • Discord doesn’t have a way for bots to stream video (there are APIs for audio), so we must use a “selfbot” or a “userbot”. This is against Discord’s terms of service, but it’s the only way forward. There are also no documented APIs for this.

Initial approach - webcam

Use a headful browser (Chrome) running Pokémon with EmulatorJS. Stream the video of headless browser to Discord. Use the stream video as a webcam input and pipe the audio as a microphone input.

This would require that the host could install kernel modules since there is a dependency on DKMS.

Result

I was able to get audio working, but not video.

Pivoting - using screen share

I really wanted to get the webcam approach working because it felt relatively elegant, but I knew I could get it done quicker if I compromised. I used a real desktop environment with xvfb and no webcam. I used Discord’s screen share functionality instead.

After about two hours of effort, this yielded a working albeit slow proof-of-concept. xvfb is not hardware accelerated, so everything is happenning in software. This is a problem when you are encoding video. The application worked, but it was unacceptable slow. Even the audio was significantly delayed. I tried downsizing the resolution from 1280x720 to 640x576, but it was still too slow.

Make it fast - hardware acceleration

Next, I needed to make the application fast.

Attempting GPU acceleration with Nvidia and Chrome

      "--disable-software-rasterizer",
      "--disable-frame-rate-limit",
      "--disable-gpu-driver-bug-workarounds",
      "--disable-gpu-driver-workarounds",
      "--disable-gpu-vsync",
      "--enable-accelerated-2d-canvas",
      "--enable-accelerated-video-decode",
      "--enable-accelerated-mjpeg-decode",
      "--enable-unsafe-webgpu",
      "--enable-features=Vulkan,UseSkiaRenderer,VaapiVideoEncoder,VaapiVideoDecoder,CanvasOopRasterization",
      "--disable-features=UseOzonePlatform,UseChromeOSDirectVideoDecoder",
      "--enable-gpu-compositing",
      "--enable-native-gpu-memory-buffers",
      "--enable-gpu-rasterization",
      "--enable-oop-rasterization",
      "--enable-raw-draw",
      "--enable-zero-copy",
      "--ignore-gpu-blocklist",
      "--use-gl=desktop"

Selkies: https://github.com/shepherdjerred/monorepo/commit/f510a9f000ea2f143a1a83ec1590d8f84f4a9db5

Chrome didn’t support Web RTC hardware acceleration on Linux, but Firefox did

Switch to Selenium due to Puppeteer limitations:

Polish

  • Disable screensaver
  • Auto-saving
  • Auto-loading game
  • Auto-loading most recent save
  • Turning bot off during inactivity
  • Web interface
  • Automatically setting Discord preferences for audio/video
  • Fully automating the process

Resources

Recent posts from blogs that I like

Advice to a beginning software engineer

In general, you should be suspicious of engineers who are trying to give you advice. Even during ordinary times, this industry is so wide and changes so quickly that nobody really knows anything for sure. And we are not in ordinary times. The advent of LLMs and AI agents is the largest change to sof...

via Sean Goedecke

U.S. Soldier Gets 70 Months in Prison for AT&T, Verizon Extortions

A U.S. Army soldier who pleaded guilty to hacking into multiple telecommunications companies and stealing mobile call and text metadata for more than 100 million AT&T customers in 2024 was sentenced to 70 months in federal prison today and ordered to pay nearly $300,000 in restitution to victims.

via Krebs on Security

American in Paris, the brief paintings of Susan Watkins

She started training at the age of 15 in New York, then in Paris, where for a decade she was one of the most successful American painters, but died soon after her return to the USA.

via The Eclectic Light Company
Live in Seattle? Let's grab coffee !
github rss email