Patents Assigned to Pixel Tools Corporation
  • Patent number: 7359439
    Abstract: A method for producing a compressed video bitstream having a plurality of frames from data that specifies a single still image. The still image is encoded into data specifying a single intra (ā€œIā€) frame having an amount of data that approaches, but remains less than, storage capacity of a buffer memory included in a decoder. A single copy of the I frame data is then combined in the compressed video bitstream with data for at least one null frame. Decoding of the compressed video bitstream assembled in this way produces frames of decoded video that do not appear to pulse visually.
    Type: Grant
    Filed: October 8, 1998
    Date of Patent: April 15, 2008
    Assignee: Pixel Tools Corporation
    Inventor: Mark D. Conover
  • Patent number: 6373960
    Abstract: A for method watermarking a compressed video bitstream selects for modification numerous sites within an MPEG compressed video bitstream, each of which sites includes a DCT coefficient which is apt for modification. Watermarking sites are preferably located in MPEG B frames, and the DCT coefficient to be modified preferably has a run-length of zero (0). The method then embeds the watermark by modifying the DCT coefficient for at least some of the selected sites. A list specifying the watermarking sites may be transmitted together with the compressed video bitstream to permit further watermarking by subsequent bitstream receivers. A system for detecting an unauthorized copy of a watermarked video forms a synchronized, frame-by-frame difference between a possibly unauthorized copy of the watermarked compressed video and an un-watermarked copy of the video. Data in the watermarking site list permits readily locating watermarks within the possibly unauthorized copy.
    Type: Grant
    Filed: January 6, 1998
    Date of Patent: April 16, 2002
    Assignee: Pixel Tools Corporation
    Inventors: Mark D. Conover, Fleming M. Oliver