US Patent 7522821 Optical disc apparatus

In an optical disc apparatus using a decoder chip with no synchronization function of audio data and visual data, when reproduction of the audio data goes ahead of reproduction of the visual data by a period equal to or larger than 100 ms, a reproducing period of a first picture included in each VOBU (Video Object Unit) is shortened than that of other pictures in the same VOBU which are normally reproduced by a normal reproducing period with no lip sync compensation for synchronizing the reproduction of the visual data with the reproduction of the audio data. When leading of the audio data with respect to the video data becomes equal to or smaller than 30 ms, the lip sync compensation is stopped.