Method and apparatus for audio-video synchronizing

Patent 5959684 Issued on September 28, 1999. Estimated Expiration Date:

July 28, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

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Inventors

Assignee

Sony Corporation

Application

No. 901090 filed on 07/28/1997

US Classes:

348/515, Audio to video348/500, SYNCHRONIZATION348/512, Locking of video or audio to reference timebase375/240.25, Specific decompression process375/240.26Associated signal processing

Examiners

Primary: Lee, Michael G.
Assistant: Desir, Jean W.

Attorney, Agent or Firm

Wood, Herron & Evans, L.L.P.

International Class

H04N 007/62

Abstract

A method and apparatus for synchronizing the playback of audio and video frames from a program source. The method associates an audio presentation time stamp ("PTS") value with an output audio frame. Selected ones of audio and video data packets include respective audio and video PTS values representing desired playback times of the respective audio and data associated therewith. The selected ones of the audio data packets further include audio frame numbers representing a number of output frames of audio to be played back between the selected ones of the audio data packets. The method comprises the steps of first storing the audio and video PTS values in respective audio and video PTS tables during an audio demultiplexing process. In addition, the audio frame numbers are stored in frame counters in association with respective PTS values during the demultiplexing process. Thereafter, the process sequentially decodes the audio and video input data to produce respective frames of audio and video which are presented to the user. With the presentation of each audio and video frame, the respective audio and video frame counters are selectively decremented. Upon detecting one of the audio frame counters having a zero value, the audio PTS value for that zero value audio frame counter is retrieved. Thereafter, the playback of the audio and video frames is selectively modified so that frames of audio and video are played back in synchronization.