Cirrus Logic Inc.

Broadcom Corporation

Other

Daniel Thomas Daum

Jeffrey G Ort

Mark A Rosenau

Tzoyao Chan

Chih-Ta Sung

Richard Chang

Daryl G Sartain

Yuanyuan Sun

George E Scott, Iii

Certain aspects of a method and system for time based wireless local area network (WLAN) scanning may include controlling scanning of a plurality of wireless access points in one or more WLANs by a WLAN station based on one or more factors comprising power consumed by the WLAN station based on the scanning, and/or a priority level of one or more media packets to be handled by the WLAN station. The information may be acquired for one or more of the plurality of wireless access points in one or more WLANs during the controlled scanning.

Method and system for time based WLAN scanning

A method of accommodating aberrant behavior in wireless devices in a wireless network includes the steps of establishing communication with at least one wireless device, monitoring signals received from the at least one wireless device, determining characteristics of the at least one wireless device based on the monitored signals, comparing the determined characteristics with prescribed characteristics for wireless devices exhibiting aberrant behavior and altering settings to accommodate the at least one wireless device, when the determined characteristics match the prescribed characteristics.

Adaptive sensitivity in wireless communication

A multimedia system which substantially integrates analog functions normally found in consumer radios (radio frequency tuner functions, volume functions), and information streams from a digital network in a single design. The system may include an Ethernet interface, central processing unit, memory, local storage device, analog to digital converter, digital to analog converter, audio output speakers, microphone, display controller, liquid crystal display panel, user interface logic, controls for tuning streams, analog and digital radio frequency tuner, and an analog storage device. The system may generate analog signals for audible reproduction. The source of audio signals may be configured in real time by the user. The hardware implementation allows for selection of broadcast radio or digital network streams such that hardware signals indicating which broadcast radio or digital stream to play from are fed to a hardware circuit which determines which stream is sent to an audio output device.

Substantially integrated digital network and broadcast radio method and apparatus

A technique for providing PCI bus mastering compatibility for legacy PCI bus devices which may not support PCI bus mastering RETRY protocols. DLDMM provider software in a device driver for a target device may provide a callback signal at a callback address to DLDMM client software in a device driver for a bus mastering PCI device. The callback address may be used by the DLDMM client software to signal the bus mastering PCI device to suspend operation in the event of an interrupting event. The bus mastering PCI device may then generate in driver software a RETRY signal to the device driver of the target device. If the interrupting event is over, a signal may be sent by the DLDMM provider software in response to the RETRY signal to the DLDMM client software indicating that the bus mastering device may resume operation. The bus mastering device may then resume operation where left off. The technique of the present invention has particular application to multimedia computer systems where a bus mastering device (e.g., MPEG decoder or the like) may wish to stream MotionVideo.TM. data to a target adapter (e.g., VGA controller or the like) using bus mastering techniques. Prior art PCI VGA adapters may not support PCI RETRY protocols and thus attempts to send data to such devices using bus mastering may fail.

PCI bus master retry fixup

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 method and system for synchronizing audio and video data signals that are in a signal format wherein the audio and video data signals are not interleaved but originate from separate sources and arrive at a constant frame rate. In one embodiment, the audio and video data signals are in an Moving Pictures Expert Group (MPEG) format. Portions of the novel system operate within the hardware of a video processor unit and portions of the novel system operate within a software driver of a computer system that receives the audio and video data signals. Audio and video data signals are referenced by a presentation time stamp (e.g., VPTS for video and APTS for audio) encoded in the data. Using these stamps, the novel system (via the video processor unit) determines if the video signal is ahead or behind the audio signal by a small number of frames, x, and if so, the video processor unit either pauses or skips frames in its video display unit hardware to regain synchronization. If the video processor unit determines that the video signal is ahead or behind the audio signal by more than x frames, a software driver operating on the computer system is informed of the difference and the software driver instructs the video processor unit to skip or pause frames within its system parsing unit hardware using a host interrupt driven mechanism to regain synchronization. Using this method, the digital video signal is effectively synchronized to the reference digital audio signal.

System and method synchronizing audio and video digital data signals

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 substantially synchronizing the display of video images with audio playback. Latency between Audio and Video decompression/decoding may be adjusted dynamically by internal hardware. Hardware signals indicating the need to skip or repeat a frame or frames of video or audio data are fed to a hardware circuit which may increment or decrement a latency value accordingly. The latency value is thus stepwise incremented or decremented until no further frame skips/repeats occur. The hardware implementation allows for better matching of latency value to audio and video decoder, frees up software for other tasks and reduces software code requirements. In addition, changes to the audio and video data paths (e.g., switching to an auxiliary audio decoder) are automatically and quickly compensated for. The hardware implementation may provide for additional levels of latency adjustment.

Auto latency correction 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 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.

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San Jose, CA, United States of America

Daniel Thomas Daum