What happens when you call someone on WhatsApp - briefly?
When you call someone on WhatsApp, the app establishes a real-time voice or video connection between your devices, allowing for instant communication similar to traditional phone calls but using internet data instead of cellular minutes. This process ensures seamless interaction regardless of geographical location, provided both parties have a stable internet connection.
What happens when you call someone on WhatsApp - in detail?
When you initiate a voice or video call on WhatsApp, several processes occur in the background to ensure seamless communication. Here’s a detailed breakdown of what happens:
-
Initialization: As soon as you tap the call button next to a contact's name, your device sends a request to WhatsApp servers. This request includes metadata such as your phone number and the recipient's phone number.
-
Connection Establishment: The WhatsApp server then attempts to establish a connection between your device and the recipient’s device. This involves several steps:
- Signal Transmission: Your device sends a signal to the WhatsApp servers, indicating that you want to start a call.
- Server Forwarding: The servers forward this signal to the recipient's device.
- Device Notification: The recipient’s device receives the signal and notifies them of the incoming call through an alert or ringtone.
-
Media Stream Setup: Once the connection is accepted, WhatsApp sets up real-time media streams for voice and video:
- Voice Call: If it's a voice call, the servers allocate resources to handle the audio stream. This includes assigning a temporary channel for the call and ensuring that the audio quality remains consistent throughout the conversation.
- Video Call: For a video call, additional resources are allocated to manage both the audio and video streams. The video stream is compressed and encoded in real-time to ensure smooth transmission over various network conditions.
-
Data Transmission: During the call, data packets containing audio or video information are continuously transmitted between your device and the recipient’s device:
- Encoding and Decoding: Your device encodes the voice or video data into a format that can be transmitted over the internet. The recipient’s device then decodes this data back into a format they can see or hear.
- Network Optimization: WhatsApp uses various techniques to optimize the call quality based on your network conditions. This includes adapting the bitrate of the streams, using forward error correction (FEC), and switching between different codecs if necessary.
-
End-to-End Encryption: Throughout the call, all data is protected by end-to-end encryption. This ensures that only you and the recipient can access the content of the conversation. No third parties, including WhatsApp itself, can intercept or decrypt the data.
-
Call Termination: When either party ends the call, a termination signal is sent to both devices:
- Resource Release: The servers release any resources allocated for the call.
- Notification: Both devices receive a notification that the call has ended, and they stop transmitting and receiving data packets.
This complex process happens in real-time, enabling users to enjoy high-quality voice and video calls on WhatsApp with minimal latency.