Method for transmitting video signals from an application on a server over an IP network to a client device

摘要

A method for transmitting a video signal from an application running on a server over an IP network to a client device. The application is drawing its content, in a plurality of sequential drawing events, into a virtual frame buffer. Simultaneously, each drawing event is registered in a list of drawing events and each drawing event is associated with an address (location) of each area that was affected by this drawing event. The list is repetitively checked and if any area have changed since previous periodic check, such area is retrieved, segmented into blocks of standardized size and transmitted, together with its address in a frame, over the IP network to the client. On the client side the encoded blocks are received and combined, using the address data, into frames of an encoded video stream that can be directly fed into an industry standard decoder of client device.

主权项

1. Method for transmitting a video signal over an IP network from a first application running on a server to a client device, said first application generating a video output that is intended to be shown as images on a display device, the method comprising:
said first application drawing its content into a virtual frame buffer on said server, in a plurality of consecutive drawing events, said content representing images to be shown, each such image comprising of a plurality of pixels, the virtual frame buffer thus at each moment of time comprising the freshest image; entering each drawing event into a list of drawing events together with data defining the image area that was affected by the corresponding drawing event; repetitively, at discrete time intervals
1. determining directly from the list of drawing events, which areas of the image have been changed by said drawing events since previous determination one discrete time interval earlier; and2. segmenting said changed areas of the image into one or more blocks of pixels, said blocks having predetermined size; storing such predetermined size blocks together with their identification data in an output buffer; and periodically, at periodic time intervals, encoding said blocks stored in the output buffer together with their identification data and transmitting said encoded blocks over the IP network to the client device.