Video data scaling for video teleconferencing workstations communicating by digital data network

A method for compressing video teleconferencing data for a distributed data processing system having a plurality of computer workstations connected by a digital data network, comprising the steps of:

• a) the source workstation scaling a frame of video data having V horizontal lines of H pixels each to reduce the quantity of horizontal lines to about V/2 and the quantity of pixels along each of the horizontal lines to about H/2 in the frame;
• b) the source workstation sending the scaled video data across the digital data network to a remote workstation;
• c) the remote workstation receiving the scaled video data from across the digital data network;
• and
• d) the remote workstation replicating the pixels of the received scaled video data to increase the quantity of horizontal lines to V and the quantity of pixels along each of the horizontal lines to H by replacing an adjacent pixel with a received pixel along a horizontal line to reconstruct the horizontal line, replacing an adjacent horizontal line with the reconstructed horizontal line, and shifting the replicated horizontal line in the horizontal direction relative to the adjacent horizontal line from which it was replicated.

A method for compressing video teleconferencing data for a distributed data processing system having a plurality of computer workstations connected by a digital data network, comprising the steps of:

• a) the source workstation scaling a frame of video data having V horizontal lines of H pixels each to reduce the quantity of horizontal lines to about V/2 and the quantity of pixels along each of the horizontal lines to about H/2 in the frame;
• b) the source workstation sending the scaled video data across the digital data network to a remote workstation;
• c) the remote workstation receiving the scaled video data from across the digital data network;
• and
• d) the remote workstation replicating the pixels of the received scaled video data to increase the quantity of horizontal lines to V and the quantity of pixels along each of the horizontal lines to H by replacing an adjacent pixel with a received pixel along a horizontal line to reconstruct the horizontal line, replacing an adjacent horizontal line with the reconstructed horizontal line., and shifting the replicated vertical column in the vertical direction relative to the adjacent vertical column from which it was replicated.

A video teleconferencing device comprising:

• a video frame grabber for capturing and storing video frames from a video source;
• a video scaler for generating scaled video frames from the stored video frames in the video frame grabber by decimating pixels of the stored video frames;
• a network controller for converting the scaled video frames into data packets in accordance with a network protocol of a digital network., for transmitting the data packets via a first one-way variable bandwidth digital data connection across the digital network to a different network transmission controller of a remote video teleconferencing device, and for receiving and converting data packets from the remote teleconferencing device into remote video frames, the data packets from the remote teleconferencing device being received via a second one-way variable bandwidth digital data connection across the digital network;
• a video descaler for descaling the remote video frames to generate descaled video frames by regenerating pixels decimated at the remote video teleconferencing device in response to pixels of the remote video frames;
• and
• a video buffer for storing the descaled video frames prior to display;
• wherein the video descaler regenerates pixels for the descaled video frames by replicating pixels of the remote video frames along the horizontal and vertical axes of the frames, and shifts one of horizontal and vertical rows of the descaled video frames by a pixel to reduce blockiness.

A video teleconferencing device, comprising:

• a video frame grabber for capturing and storing video frames from a video source;
• a video scaler for generating scaled video frames from the stored video frames in the video frame grabber by decimating pixels of the stored video frames;
• a network controller for converting the scaled video frames into data packets in accordance with a network protocol of a digital network, for transmitting the data packets via a first one-way variable bandwidth digital data connection across the digital network to a different network transmission controller of a remote video teleconferencing device, and for receiving and converting data packets from the remote teleconferencing device into remote video frames, the data packets from the remote teleconferencing device being received via a second one-way variable bandwidth digital data connection across the digital network;
• a video descaler for descaling the remote video frames to generate descaled video frames by regenerating pixels decimated at the remote video teleconferencing device in response to pixels of the remote video frames;
• and
• a video buffer for storing the descaled video frames prior to display;
• wherein the video descaler replicates each pixel of the remote video frames into an adjacent pixel along one of the horizontal and vertical axes to form complete rows, and then replicates the complete rows into adjacent rows along the other one of the horizontal and vertical axes, and shifts one of horizontal and vertical rows of the descaled video frames by a pixel to reduce blockiness.

A video teleconferencing device, comprising:

• a network controller for receiving data packets from a remote teleconferencing device via a one-way variable bandwidth digital data connection across a digital network and for converting the data packets into remote video frames;
• a video descaler for descaling the remote video frames to generate descaled video frames by regenerating pixels decimated at the remote video teleconferencing device in response to pixels of the remote video frames;
• and
• a video buffer for storing the descaled video frames prior to display;
• wherein the video descaler regenerates pixels for the descaled video frames by replicating pixels of the remote video frames along the horizontal and vertical axes of the frames, and shifts one of horizontal and vertical rows of the descaled video frames by a pixel to reduce blockiness.

A video teleconferencing device, comprising:

• a network controller for receiving data packets from a remote teleconferencing device via a one-way variable bandwidth digital data connection across a digital network and for converting the data packets into remote video frames;
• a video descaler for descaling the remote video frames to generate descaled video frames by regenerating pixels decimated at the remote video teleconferencing device in response to pixels of the remote video frames;
• and
• a video buffer for storing the descaled video frames prior to display;
• wherein the video descaler replicates each pixel of the remote video frames into an adjacent pixel along one of the horizontal and vertical axes to form complete rows, then replicates the complete rows into adjacent rows along the other one of the horizontal and vertical axes, and shifts one of horizontal and vertical rows of the descaled video frames by a pixel to reduce blockiness.