Abstract: In a video image compression and transmission system, quantization parameters for a block transform based video compression algorithm can be controlled by a quantizer selector so as to control compressed video frame size. The selection of the appropriate quantization parameter for the nth macroblock of a current frame is based on the cumulative number of compressed bits appearing in the first n-1 macroblocks of a current frame and a previous frame. By controlling the quantization parameter is such a manner, the overall system reacts more quickly to changes in complexity in the video sequence and allocates bits more accurately to different parts of the video frame according to a past history of bit allocation. To efficiently utilize the bandwidth of a transmission medium (such as POTS), a bit count of the contents of the transmit buffer is sent to a buffer regulator in a video controller where it is compared to a low water mark threshold.

Abstract: An apparatus is programmed with a video service for facilitating video communication with another remote apparatus, in accordance with a video communication protocol. The video service includes a still image function with logic for providing a plurality of progressive scans of one or more still images to the remote apparatus, in accordance with a still image communication protocol defined within the video communication protocol. In one embodiment, the still image function includes logic for instructing a local video capture driver to switch to a format of the still image function's choice for capturing video image frames, holding constant video image input to a video codec to generate the plurality of progressive scans of the still images, and implementing the still image communication protocol.

Abstract: A method for creating a video connection between a video source for transmitting frames of video data and a video sink for receiving the frames. The video source may be a file, a camera, a computer network, and a telephony interface. The video sink may be a file, a visual display device, a computer network, and a telephony interface. The video source has a recycle framehandler function for recycling used buffers and the video sink has a process framehandler function for processing received frames. A video stream object is created having data members that include a reference to the video sink and a reference to the video source, as well as several member functions. The member functions are used to query the video sink to obtain a reference to the process framehandler function and to then provide the reference to the video source. The member functions are also used to query the video source to obtain a reference to the recycle framehandler function, which is then provided to the video sink.

Abstract: A video system is disclosed that provides fast communication packet loss recovery. A source node generates a series of encoded video flames for a series of digitally sampled video flames by encoding each digitally sampled video frame relative to either an immediately preceding digitally sampled video frame or a previous digitally sampled video frame specified by a lost frame message received over the communication link from a destination node. The destination node receives the encoded video frames over the communication link and transfers the lost frame message to the source node if one of the encoded video frames is lost or delayed. The destination node generates the decoded version of each encoded video frame relative to either a decoded version of an immediately preceding encoded video frame or a decoded version of a last successfully received encoded video frame.

Abstract: A method of handling processor to processor interrupt requests in a multiprocessing computer bus environment is described. This method allows a multiple-tiered, increasing priority, interrupt request scheme. This method also allows processor to processor directed interrupt requests, processor to one processor of a group of processors interrupt requests, and processor to all processors of a group of processors interrupt requests.