Channel synchronized audio data compression and decompression for an in-flight entertainment system

摘要

In an In-Flight Entertainment System (IFES), an audio distribution system transmits and synchronizes an audio data stream from multiple audio channels using the Adaptive Differential Pulse Code Modulation (ADPCM) technique for efficient transmission and preventing loss of synchronization. An encoder digitizes the analog audio signals, compresses the digital data, generates the synchronization parameters, including synchronization data for a selected channel, and creates a data frame to be transmitted to a number of decoders. Each decoder detects the synchronization header, extracts the compressed data patterns from the passenger selections, updates the ADPCM synchronization parameters, decompresses the compressed data patterns, and converts the digital audio data to analog audio signals to be delivered to the passenger seats.