Table of content:

• Functional Requirements
• Non Functional Requirements
• Capacity Estimation
• High Level System Design
• Algorithms

Video Calling applications such as zoom/skype uses adaptive streaming to improve users realtime experience.

Functional Requirements

1. Video calling should support peer-to-peer and video conferences
2. System should support 300M video calls/day
3. System should support Adaptive streaming
4. System should adopt Scalable Video Coding

Non-Functional Requirements

1. System should be highly reliable and scalable
2. System should be highly available, loosing some frames is acceptable.

Capacity Estimation

Throughput

• Throughput : 300M/10^5= 3000 Calls/sec.

Storage

• Video recording stored in their local machines

High Level System Design

IMPORTANT NOTES

• Adjusting resolution based on device type and bandwidth is called adaptive streaming.
• Number of pixels in a video frame is called resolution
• Sending many video streams for different resolutions isn’t scalable
• System should use Scalable Video Coding (SVC) to stream video.

Algorithms