Audio adaptation according to usage environment and perceptual quality metrics

Future audio applications will need to handle a wide variety of end-devices and networks from low quality mobile services to very high quality home entertainment services. The MPEG-21 Digital Item Adaptation standard specifies a variety of tools that aim to enhance the user experience and maximize the perceived quality of service. This paper focuses on the audio-related tools, including audio usage environment descriptions and techniques for audio resource adaptation. Additionally, subjective and objective measures are discussed in the context of bit-rate adaptation. New quality measures, brightness, cleanness, and wideness are proposed for controlling the quality of the audio transmission.