Carrot Talk
描述:

The project of Carrot Talk is an intelligent iPad application that provides gateway management for the end users of The Java located in 98 Java Road, North Point.

Technical Highlight
Since the key of this application is allowing a smooth communication (both video and audio) between the two users, the main challenge of this project is to communicate with different hardwares (video & audio server, and the gateway server) in very low latency output. The following are some key technology we used in the application:

For Live Video Streaming
•    MJPEG format, D1 quality, 25 FPS
•    Using TCP socket to retrieve video data
•    Using ring-buffering to maintain a smooth video

For Live 2-way Talking
•    u-law encoding, 24kHz, 8 bit
•    Using UDP socket to retrieve audio data
•    Using Core Audio Unit (iOS) to have low latency performance
•    Using Low-pass / High-pass filtering to avoid background noise
•    Using ring-buffering to maintain a smooth audio

For Gateway Communication
•    Communicate with a web services (CGI command)
•    Using a response timer to handle the data lost

For Security Management
•    Using custom encryption for data transmission
•    Using a lock to ensure only one user could communicate with the gateway at a time

Hardware Specification

Door-end
•    Gateway Panel
•    Speaker & Microphone
•    Digital Camera

Back-bone
•    Video & Audio Server
•    Gateway Server
•    Back-bone networking
•    Wifi Environment for each floor and room

User-end
•    iPad2 with iOS 4.3+