IMPROVING TRANSIENT PERFORMANCE OF LOW BIT RATE AUDIO CODING SYSTEMS BY REDUCING PRE-NOISE

摘要

Distortion artifacts preceding a signal transient in an audio signal streamprocessed by a transform-based low-bit-rate audio coding system employingcoding blocks are reduced by detecting a transient in the audio signal streamand shifting the temporal relationship of the transient with respect to thecoding blocks such that the time duration of the distortion artifacts isreduced. The audio data is time scaled in such a way that the transients aretemporally repositioned prior to quantization in a transform-based low-bit-rate audio encoder so as to reduce the amount of pre-noise in the decodedaudio signal. Alternatively, or in addition, in a transform-based low-bit-rateaudio coding system, a transient in the audio signal stream is detected and aportion of the distortion artifacts are time compressed such that the timeduration of the distortion artifacts is reduced.