Patents by Inventor Dazhong Zhang

Dazhong Zhang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8340194
    Abstract: Disclosed is an exemplary video coder and video coding method according to an embodiment of the present invention. The exemplary video coder includes a scheduler, a plurality of processors and a multiplexer. The scheduler can examine processing units in an input buffer to determine an order for the processing unit to be coded by a processor. If the processing unit under examination depends on a processing unit not yet processed, the processing unit under examination can be merged with other processing units, if any, that share a similar dependency. If the processing unit under examination does not depend on any processing units not yet processed, it can be sent to a next available processor for coding. When a processing unit is sent to a processor, any merged processing units that depend on sent processing unit can also be sent to a next available processor.
    Type: Grant
    Filed: June 5, 2009
    Date of Patent: December 25, 2012
    Assignee: Apple Inc.
    Inventors: Jochen Christian Schmidt, Paul Seung Ho Chang, Chris Yoochang Chung, Christian Luc Duvivier, Ionut Hristodorescu, Hsi-Jung Wu, Dazhong Zhang, Xiaosong Zhou
  • Publication number: 20120170654
    Abstract: A video coding/decoding system builds implied reference frames from a plurality of reference frames developed during coding. Coded data of reference pictures are decoded and stored in a reference picture cache. An implied reference frame may be derived from a plurality of reference frames and may be stored in the reference picture cache. Thereafter, coding of new input data may proceed using the implied reference frame as a source of prediction. The method may be used to identify visual elements such as background elements that may persist in video over a longer period that can be captured by the system under conventional reference frames assembly and eviction. Implied reference frames may be built at both an encoder and a decoder to serve as sources of prediction.
    Type: Application
    Filed: January 7, 2011
    Publication date: July 5, 2012
    Applicant: APPLE INC.
    Inventors: Ke Zhang, Dazhong Zhang, Douglas Scott Price, Hsi-Jung Wu, Xiaosong Zhou
  • Publication number: 20120106632
    Abstract: A system and method for coding video data wherein a pixel block may be coded for refresh with reference to an LTR frame that was successfully transmitted, or has a high probability of having been successfully transmitted from the encoder to the decoder. Not all pixel blocks in the frame may be refreshed at the same rate. Pixel blocks containing edge details, containing a significant object, or containing foreground image data may be refreshed more often than pixel blocks containing smooth, background, or relatively less significant image data.
    Type: Application
    Filed: October 28, 2010
    Publication date: May 3, 2012
    Applicant: APPLE INC.
    Inventors: Dazhong Zhang, Xiaosong Zhou, Hsi-Jung Wu
  • Publication number: 20110302473
    Abstract: Coded video data may be transmitted between an encoder and a decoder using multiple FEC codes and/or packets for error detection and correction. Only a subset of the FEC packets need be transmitted between the encoder and decoder. The FEC packets of each FEC group may take, as inputs, data packets of a current FEC group and also an untransmitted FEC packet of a preceding FEC group. Due to relationships among the FEC packets, when transmission errors arise and data packets are lost, there remain opportunities for a decoder to recover lost data packets from earlier-received FEC groups when later-received FEC groups are decoded. This opportunity to recover data packets from earlier FEC groups may be useful in video coding and other systems, in which later-received data often cannot be decoded unless earlier-received data is decoded properly.
    Type: Application
    Filed: June 4, 2010
    Publication date: December 8, 2011
    Applicant: Apple Inc.
    Inventors: Xiaosong ZHOU, Hyeonkuk JEONG, Yan YANG, Dazhong Zhang, Hsi-Jung WU
  • Publication number: 20110274167
    Abstract: A coding technique is disclosed in which frames of a video sequence are assigned to one of a plurality of sub-channels to be transmitted to a decoder. The frames are coded according to predictive coding techniques such that ordinarily prediction references of the frames in each sub-channel only reach the reference frames that occur within the same sub-channel. Thus, if transmission errors arise with respect to one sub-channel, decoding may occur for another sub-channel until the transmission error is detected and corrected.
    Type: Application
    Filed: July 1, 2011
    Publication date: November 10, 2011
    Applicant: APPLE INC.
    Inventors: Dazhong Zhang, Hsi-Jung Wu, Xiaosong Zhou
  • Publication number: 20110249075
    Abstract: Some embodiments provide a method for allowing a first device that is in a video conference with a second mobile device to remotely control the second mobile device. The method sends images captured by a camera of the first device to the second device. The method receives images captured by a camera of the second device. The method sends a command through a communication channel of a real-time communication session to the second device. The command is for instructing the second device to perform an operation that modifies the images captured by the camera of the second device.
    Type: Application
    Filed: June 6, 2010
    Publication date: October 13, 2011
    Inventors: JOE S. ABUAN, JAMES O. NORMILE, HSI-JUNG WU, HAITAO GUO, DOUGLAS S. PRICE, XIAOSONG ZHOU, DAZHONG ZHANG, BERKAT S. TUNG, ROBERTO GARCIA, JR., HYEONKUK JEONG, YAN YANG, DAVID A. ELDRED, ELIZABETH C. CRANFILL, ANDREW YANOWITZ, TING CHEN, DAVID D. KUO
  • Publication number: 20110249729
    Abstract: Embodiments of the present invention provide a video encoding system that codes video sequence into a multi-level hierarchy based on levels of long term reference (LTR) frames. According to the present invention, an encoder designates a reference frame as a long term reference (LTR) frame and transmits the LTR frame to a receiver. Upon receiving feedback from the receiver acknowledging receipt of the LTR frame, the encoder periodically codes subsequent frames as reference frames using the acknowledged LTR frame as a reference and designates subsequent reference frames as secondary LTR frames. A determined number of frames after each secondary LTR frame may be coded using a preceding secondary LTR frame as a reference.
    Type: Application
    Filed: June 4, 2010
    Publication date: October 13, 2011
    Applicant: Apple Inc.
    Inventors: Xiaosong ZHOU, Dazhong Zhang, Davide Concion, Hsi-Jung Wu, Douglas Scott Price
  • Publication number: 20110249133
    Abstract: Embodiments of the present invention provide a video encoding system in which a video coding engine establishes coding quality metrics that govern its own operation as well as the operation of a camera and/or a pre-processor. An imaging system may include an image acquisition system, a pre-processor and a coding engine. The coding engine may output a quality indicator identifying, for each portion of a video sequence currently being coded, a relatively level of coding quality that is being achieved. The imaging system further may include an image acquisition controller and a pre-processor controller that impose respective operating parameters upon the image acquisition system and the pre-processor in response to these quality indicators. In this manner, overall performance of the imaging system may be improved.
    Type: Application
    Filed: June 4, 2010
    Publication date: October 13, 2011
    Applicant: APPLE INC.
    Inventors: Xiaosong ZHOU, Douglas Scott PRICE, Hsi-Jung WU, Dazhong ZHANG
  • Publication number: 20090310685
    Abstract: Disclosed is an exemplary video coder and video coding method according to an embodiment of the present invention. The exemplary video coder includes a scheduler, a plurality of processors and a multiplexer. The scheduler can examine processing units in an input buffer to determine an order for the processing unit to be coded by a processor. If the processing unit under examination depends on a processing unit not yet processed, the processing unit under examination can be merged with other processing units, if any, that share a similar dependency. If the processing unit under examination does not depend on any processing units not yet processed, it can be sent to a next available processor for coding. When a processing unit is sent to a processor, any merged processing units that depend on sent processing unit can also be sent to a next available processor.
    Type: Application
    Filed: June 5, 2009
    Publication date: December 17, 2009
    Applicant: APPLE INC.
    Inventors: Jochen Christian SCHMIDT, Paul Seung Ho CHANG, Chris Yoochang CHUNG, Christian Luc DUVIVIER, Ionut HRISTODORESCU, Hsi-Jung WU, Dazhong ZHANG, Xiaosong ZHOU