Method of video transmission and display
Aspects of the present disclosure relate to a method, in a video output device, for acquiring video data for outputting to a display. The method comprises subscribing to a multicast stream of a plurality of multicast streams. Each multicast stream is streamed from a video source and comprises video frame data corresponding to a portion of a video frame. The multicast stream to which the video output device subscribes comprises video frame data that is for display on a display associated with the video output device. The method then comprises receiving the video frame data that is for display on the display.
1. A method for encoding a frame of original video data by a component of a video system into a plurality of frames for inclusion in video streams of different spatial resolutions, the method comprising:
dividing the original frame of original video data into grids each grid containing a predetermined number of pixel values;
summing pixel values within each of the grids of pixel values to form a total pixel value for each grid of pixel values;
encoding the total pixel values to form a downscaled frame;
encoding the original pixel values in each of the plurality of grids of pixel values to form a higher resolution frame, wherein fewer than all the pixel values within each grid of pixel values are encoded in the higher resolution frame and a final pixel value of each grid that is not encoded is derivable using the encoded total value of a corresponding grid of the downscaled frame and the pixel values encoded in the grid of the higher resolution frame,
wherein the method is a lossless encoding such that the downscaled frame and the higher resolution frame allow recreation of the original frame without loss.
2. A method according to claim 1 wherein the component of the video system is configured to form a downscaled frame that has a resolution that is at least one of a half, quarter or eighth resolution of the original video data.
3. A method according to claim 1 , wherein the frame of original video data is a frame of original video data comprising a single colour component.
4. A method according to claim 3 , wherein the single colour component is one of luminance, red-difference chroma and blue difference chroma.
5. A method according to claim 1 , wherein one or more further downscaled frame is formed by dividing a preceding downscaled frame into grids each grid containing a predetermined number of pixel values;
summing pixel values within each of the grids of pixel values of the preceding downscaled frame to form a total pixel value for each grid of pixel values; and
encoding the total pixel values to form the further downscaled frame.
6. A method according to claim 5 , comprising forming a final downscaled video frame that encodes an accumulated total of all the pixel values from the original video frame.
7. A method according to claim 1 further comprising forming a first video stream comprising the downscaled frame and forming a second video stream comprising the higher resolution frame.
8. A method according to claim 1 further comprising dividing each total pixel value by the number of pixels in the grid prior to encoding the total pixel values to form a downscaled frame.
9. A method for decoding a frame of video data by a component of a video system, the method comprising:
obtaining downscaled video data for a downscaled frame, the downscaled video data encoding total values of pixels for grids of a higher resolution frame;
obtaining enhanced video data for the higher resolution frame, the enhanced video data encoding fewer than all the pixel values that form the grids of the higher resolution frame; and
determining pixel values for all pixels of a grid of the higher resolution frame by deriving at least one missing pixel value from the total pixel value of the corresponding grid of the downscaled frame and the pixel values of the grid encoded in the enhanced video data.
10. A component of a video system comprising a processor and a non-transitory computer-readable storage medium comprising a set of instructions that, when executed by the processor, cause the component to perform a method for encoding a frame of original video data into a plurality of frames for inclusion in video streams of different spatial resolutions, the method comprising:
dividing the original frame of original video data into grids each grid containing a predetermined number of pixel values;
summing pixel values within each of the grids of pixel values to form a total pixel value for each grid of pixel values;
encoding the total pixel values to form a downscaled frame;
encoding the original pixel values in each of the plurality of grids of pixel values to form a higher resolution frame, wherein fewer than all the pixel values within each grid of pixel values are encoded in the higher resolution frame and a final pixel value of each grid that is not encoded is derivable using the encoded total value of the corresponding grid of the downscaled frame and the pixel values encoded in the grid of the higher resolution frame
wherein the method is a lossless encoding such that the downscaled frame and the higher resolution frame allow recreation of the original frame without loss.