How does Rabb.it stream broswer windows for users

Rabb.it, which has been rebranded as Kast, offered a unique way for users to stream browser windows, videos, and other content in a shared, synchronized manner. The service essentially allowed users to watch videos together in real-time, much like a virtual living room. Here’s how Rabb.it managed to stream browser windows for its users:

1. Virtual Browser Instances

Rabb.it used cloud-based virtual machines to create browser instances. Here’s how it worked:

  • Virtual Machine (VM) Setup: When a user initiated a session, Rabb.it would spin up a virtual machine in the cloud. This VM ran a full-fledged web browser.
  • Browser Control: The user who started the session had control over this browser, able to navigate websites, play videos, and interact with web content as they would on their local machine.

2. Screen Capture and Streaming

  • Screen Capture: Rabb.it captured the video output of the virtual browser running on the VM. This involved capturing the screen content at regular intervals to create a stream of the browser window.
  • Audio Capture: Similarly, the audio output from the VM (such as video soundtracks or audio from web applications) was captured.

3. Real-time Video Encoding

  • Video Encoding: The captured video and audio streams were then encoded in real-time using video compression technologies such as H.264. This encoding process ensured that the video stream was optimized for transmission over the internet, balancing quality and bandwidth usage.

4. Content Delivery

  • Streaming to Users: The encoded video and audio streams were sent to Rabb.it’s servers, which then distributed the stream to all participants in the session. This required efficient content delivery networks (CDNs) to minimize latency and ensure smooth playback.
  • Synchronization: Rabb.it synchronized the playback across all viewers, ensuring everyone saw the same content at the same time. This was crucial for the shared viewing experience.

5. User Interface and Interaction

  • User Interface (UI): Users interacted with a web-based or application-based interface that displayed the shared content. The UI also included chat functionalities, user controls, and other interactive elements.
  • Control Passing: The session host could pass control of the virtual browser to other participants, allowing them to navigate or interact with the web content.

Technical Challenges and Solutions

  • Latency Management: Ensuring minimal latency was critical to provide a seamless viewing experience. Rabb.it utilized CDNs and optimized their encoding and streaming processes to reduce delays.
  • Scalability: Managing multiple concurrent sessions required scalable cloud infrastructure to handle the computational load of running many virtual machines and encoding streams simultaneously.
  • Quality of Service: Balancing video quality and bandwidth was important, especially for users with varying internet speeds. Adaptive streaming techniques were likely used to adjust the stream quality based on the user’s network conditions.

Transition to Kast

After Rabb.it ceased operations, Kast acquired its assets and continued to offer similar services, building upon the technology and experience of Rabb.it. Kast has further developed these capabilities, allowing users to share not just browser windows but also entire desktops, applications, and more, enhancing the communal viewing and interaction experience.

In summary, Rabb.it’s technology involved using cloud-based virtual machines to run browser instances, capturing and encoding the screen and audio output in real-time, and streaming this content to multiple users with minimal latency, all managed through a user-friendly interface.