System and method for providing interactive audio in a multi-channel audio environment

Abstract

DTS Interactive provides low cost fully interactive immersive digital surround sound environment suitable for 3D gaming and other high fidelity audio applications, which can be configured to maintain compatibility with the existing infrastructure of Digital Surround Sound decoders. The component audio is stored and mixed in a compressed and simplified format that reduces memory requirements and processor utilization and increases the number of components that can be mixed without degrading audio quality. Techniques are also provided for “looping” compressed audio, which is an important and standard feature in gaming applications that manipulate PCM audio. In addition, decoder sync is ensured by transmitting frames of “silence” whenever mixed auedio is not present either due to processing latency or the gaming application.

1 . A method of preparing PCM audio data for storage in a compressed format that is compatible with looping, wherein said PCM audio data is stored in a file and the compressed format includes a sequence of compressed audio frames comprising: 
 a. Compacting or dilating the PCM audio data in time to fit the boundaries defined by a whole number of compressed audio frames to form a looped segment;    b. Appending N frames of PCM audio data from the end of the file to the start of the looped segment;    c. Encoding the looped segment into a bitstream; and    d. Deleting N compressed frames from the beginning of the encoded bitstream to yield a compressed audio loop sequence in which the compressed audio data in the closing frames of the loop sequence ensure seamless concatenation with the commencing frames during looping.