US 11,817,885 B2
Guaranteed data compression
Simon Fenney, St Albans (GB); and Linling Zhang, Watford (GB)
Assigned to Imagination Technologies Limited, Kings Langley (GB)
Filed by Imagination Technologies Limited, Kings Langley (GB)
Filed on Mar. 17, 2022, as Appl. No. 17/697,836.
Application 17/697,836 is a continuation of application No. 17/076,182, filed on Oct. 21, 2020, granted, now 11,309,907.
Application 17/076,182 is a continuation of application No. 16/457,958, filed on Jun. 29, 2019, granted, now 10,819,367, issued on Oct. 27, 2020.
Claims priority of application No. 1810794 (GB), filed on Jun. 29, 2018.
Prior Publication US 2022/0209790 A1, Jun. 30, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H03M 7/30 (2006.01); H04N 19/103 (2014.01); H04N 19/119 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/42 (2014.01)
CPC H03M 7/3059 (2013.01) [H03M 7/6005 (2013.01); H03M 7/6011 (2013.01); H04N 19/103 (2014.11); H04N 19/119 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/42 (2014.11)] 20 Claims
OG exemplary drawing
 
1. A lossy method of compressing data comprising:
for each of at least one sub-block of a block of pixels:
analysing an alpha channel value for each pixel in the sub-block to compress the sub-block using a compression mode which uses a fixed alpha channel value for pixels in the sub-block.