US 12,126,835 B2
Method and apparatus for non-separable transform selection in an encoder and decoder
Christopher Hollmann, Uppsala (SE); Davood Saffar, Solna (SE); Per Wennersten, Årsta (SE); and Jacob Ström, Stockholm (SE)
Assigned to Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Appl. No. 17/621,059
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Jun. 15, 2020, PCT No. PCT/EP2020/066508
§ 371(c)(1), (2) Date Dec. 20, 2021,
PCT Pub. No. WO2020/254256, PCT Pub. Date Dec. 24, 2020.
Claims priority of provisional application 62/864,601, filed on Jun. 21, 2019.
Prior Publication US 2022/0337877 A1, Oct. 20, 2022
Int. Cl. H04N 19/70 (2014.01); H04N 19/12 (2014.01); H04N 19/169 (2014.01); H04N 19/172 (2014.01); H04N 19/176 (2014.01); H04N 19/60 (2014.01)
CPC H04N 19/70 (2014.11) [H04N 19/12 (2014.11); H04N 19/172 (2014.11); H04N 19/176 (2014.11); H04N 19/1883 (2014.11); H04N 19/60 (2014.11)] 11 Claims
OG exemplary drawing
 
5. A decoder comprising:
a processor; and
memory coupled with the processor, wherein the memory comprises instructions that when executed by the processor cause the decoder to perform operations comprising:
receiving a bit stream having an encoded video block encoded with a multiple transform selection, MTS, index;
receiving a set descriptor from the bit stream once per frame, once per sequence of frames, once per coding tree unit, or once per coding unit;
parsing the set descriptor to determine a predetermined set of indices;
parsing the MTS index to determine a value of the MTS index;
determining whether the value is one of a predetermined set of indices;
responsive to the value being one of the predetermined set of indices:
parsing a low frequency non-separable transform, LFNST, index from the bit stream to determine a value of the LFNST index, the value indicating whether a LFNST transform set is to be used in decoding the encoded video block; and
responsive to the value not being one of the predetermined set of indices:
setting the value of the LFNST index to a default value indicating no LFNST transform is to be used in decoding the encoded video block; and
decoding the encoded video block based on the value of the MTS index and the value of the LFNST index.