Abstract: A system encodes an image for a remote client. A graphics processor unit (GPU) renders an image in response to graphics commands received from a central processing unit (CPU) virtual machine. Image attributes are determined by display requirements from the remote client. A display encoder is associated with the GPU, encodes the image, and operates independent of the rendering of the image. A network interface may be associated with the CPU, GPU or display encoder and may transmit the encoded image across a network to the remote client.

Abstract: A method of transmitting visual data from a host computer to multiple displays across a computer network is disclosed. Visual data is stored in a plurality of frame buffers, each frame buffer associated with a separate display. A frame buffer update sequence is determined, with operations to be performed on frame buffers in the plurality. The data stored in the plurality of frame buffers is encoded as specified by the buffer update sequence to yield encoded images and each encoded image is sent across a computer network to the separate display associated with the frame buffer from which the encoded image was derived.

Abstract: A method and apparatus for calculating the quantized difference between a pixel in a current frame and a pixel in a reference frame is disclosed. The apparatus of the present invention generates a “1 of n” significant difference bit output which may easily be logically OR'd with the difference values from other comparisons to determine the maximum difference over an area of pixels.

Abstract: A method of transmitting encoded computer display images between computers over a nondeterministic network is disclosed. During a display session in which images are transmitted from a host to a client, the client requests sections of encoded image updates at a predetermined time in advance of when the requested at least one section is to be transmitted by the display controller. When the requested section is received, a time value is compared to a display controller timing value and, if the difference between the compared times is outside of an acceptable range, the client adjusts a predetermined time at which time the client requests image sections from the host.

Abstract: Decomposing a computer display image into different layer types and associated masks based on the unique nature of the image is disclosed. These types include text, objects, background and pictures. A set of image masks is used to uniquely identify different layer types within an image, where each layer type includes none, some or all of the pixels of the original image. Each layer of the image is processed prior to transmission (i.e. compressed) using a method appropriate for the characteristics of that layer.

Abstract: A method and apparatus for comparing portions of data from a digital raster signal to a plurality of scan blocks of data, where each scan block in the plurality describes either a defined image area or entire image frame is disclosed. Included are a hashing function that calculates hash codes for spatially-defined segments of an incoming raster signal; a recent scan hash table containing hash codes for scan blocks received within a specified time period; a comparator for comparing calculated hash codes for the spatially-defined segments of the incoming raster signal with hash codes stored in the recent scan hash table; a pixel capture and timing module for capturing a digital raster signal; and an output selector for selecting for transmission a compressed form of a scan block, a hash code index, or no data if a scan block exists in a remote frame playout buffer.

Abstract: A pair of processing modules and methods that enable low latency communications between a data processing system and devices located at a remote graphic user interface across a standard shared network in accordance with the present invention is disclosed. The present invention provides a method for communicating graphics data in a synchronous manner from the data processing system to the user. This method is used in conjunction with a feedback error recovery method to provide lossless, low-latency communications of graphics data across the network.

Abstract: A method of transmitting encoded computer display images between computers over a nondeterministic network is disclosed. During a display session in which images are transmitted from a host to a client, the client requests sections of encoded image updates at a predetermined time in advance of when the requested at least one section is to be transmitted by the display controller. When the requested section is received, a time value is compared to a display controller timing value and, if the difference between the compared times is outside of an acceptable range, the client adjusts a predetermined time at which time the client requests image sections from the host.