Cirrus Logic Inc.

Chips and Technologies, Llc.

Mark A Rosenau

Daniel Thomas Daum

Jeffrey G Ort

Arun Johary

Tzoyao Chan

Chih-Ta Sung

Richard Chang

Daryl G Sartain

Yuanyuan Sun

A multimedia system including an audio/video decoder/decompresser for decoding/decompressing a compressed encoded audio/video data stream to generate video images for display and audio signals for audible reproduction. The multimedia system includes an integrated system and video decoder with an audio/video synchronization circuit for substantially synchronizing the display of video images with audio playback. In addition, a step control is provided to allow for viewing of video images on a frame-by frame basis or to freeze or play video in slow motion. When step control is activated, audio output is muted. Audio data corresponding to displayed video is transmitted to the muted audio decoder. An internal system clock may be suppressed to the system clock counter. An external CPU may provide system clock start times corresponding to video frames to be displayed. The external CPU may increment the system clock counter by a an amount corresponding to the difference between a successive frame or number of frames. When nominal playback is resumes, the audio and video data streams are substantially in synchronization.

Stream synchronization method and apparatus for MPEG playback system

A multimedia system including an audio/video decoder/decompresser for decoding/decompressing a compressed encoded audio/video data stream to generate video images for display and audio signals for audible reproduction. The multimedia system includes an integrated system and video decoder with an audio/video synchronization circuit for substantially synchronizing the display of video images with audio playback. An audio presentation time stamp (APTS) is detected in the compressed/coded audio data stream in the integrated system and video decoder and stored in a data latch. The compressed/coded audio data stream is fed to an audio decoder which decodes/decompresses the audio data and outputs and audio signal. The audio decoder detects when audio data corresponding to an APTS had been output and sets a corresponding flag. The flag indicates to the integrated system and video decoder that a corresponding audio segment had been decoded/decompressed and output. The integrated system and video decoder then synchronizes the video output with the audio output by repeating or skipping frames of video data.

Method and apparatus for audio and video synchronizing in MPEG playback

A multimedia system including an audio/video decoder/decompresser for decoding/decompressing a compressed encoded audio/video data stream to generate video images for display and audio signals for audible reproduction. The multimedia system includes an integrated system and video decoder with an audio/video synchronization circuit for substancially synchronizing the display of video images with audio playback. A method is described for detecting when the playback of audio and the display of video images are out of synchronization. The circuitry includes three programmable registers, a finite state machine and one full adder using an audio presentation time stamp and the video presentation time stamp. The method uses a rounded programmable bias value which is compared with the difference between the video presentation time stamp and the audio presentation time stamps. The difference may included the latency delay of the audio and video display devices to more properly reflect the synchronization status between audio and video. The circuit area used by the circuitry has been minimized by selective rounding or truncation of the audio presentation time stamp and the video presentation time stamp without sacrificing the accuracy or speed of determining the synchronization between audio and video.

Programmable audio-video synchronization method and apparatus for

A method and apparatus for scaling interlaced video data allows the video data to be scaled to any desired size, either larger or smaller than the original image. The method considers each line of input data in each field sequentially, and determines whether the line is to be saved and whether the data lines in each successive field will also be saved, discarded, or duplicated, saving space in the output buffer for the saved and duplicated data lines to come as necessary. The method can accommodate interlaced data with N field and a scaling factor M.

Method and apparatus for scaling interlaced images

A method and apparatus for scaling interlaced video data allows the video data to be scaled to any desired size, either larger or smaller than the original image. The method considers each line of input data in each field sequentially, and determines whether the line is to be saved and whether the data lines in each successive field will also be saved, discarded, or duplicated, saving space in the output buffer for the saved and duplicated data lines to come as necessary. The method can accommodate interlaced data with N field and a scaling factor M. An apparatus for implementing the method for two header fields and scaling factor N is also described.

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San Jose, CA, United States of America

Mark A Rosenau