Preservation of local sound periodicity with variable-rate video

Abstract

A method of allowing pitch preservation of sound with variable-rate video playback is suggested. This is an important factor in monitoring of audio content for cueing purposes. Methods of separately considering a signal's frequency and time representations are considered with a view to performing time-scale modification with preservation of local periodicity (pitch). Particular emphasis is placed upon granulation in time of a sampled source — a technique based upon Dennis Gabor's landmark papers in 1946 and 1947 and developed in the field of computer music. This relatively simple method requires no prior signal analysis and is therefore a less computationally expensive method of achieving the goals stated above. This is an important point considering the need for real-time implementation. The process does however introduce some distortion, and investigation into how this may be minimised is necessary to produce acceptable results.