On the utilization of overshoot effects in low-delay audio coding

In low-delay audio coding (coding delay <5 ms) there is no time for detailed spectral modeling in the case of brief percussive sounds, e.g., the castanets, and onsets of music or speech sounds. On the other hand, it is known from psychoacoustic experiments that the ear is not accurate near the onset of a wideband sound. In this paper, we study the audibility of coding errors near the onsets of musical sounds in a simulated low-delay audio codec based on frequency-warped linear prediction. It is suggested that for many musical transients it is sufficient to reproduce a rough temporal and spectral envelope of the original signal during the first 5-10 ms. Preliminary listening tests support this idea. It is proposed that the overshoot effect of hearing could be utilized efficiently in enhancing the performance of a low-delay audio coding scheme.