JVET-AM0237 On constrained encoding and decoding experiments [L. Li, M. W. Park, M. Park, Y. Kim, M. Budagavi, K. P. Choi (Samsung)]

This contribution explores the trade-offs between coding efficiency and computational complexity for both encoder and decoder. During the previous meeting, multiple trade-off points were presented by changing ECM configurations. While certain configurations demonstrated encoder complexity levels approximately twice that of the VTM encoder, the corresponding decoder complexity failed to achieve a desired two times of VTM decoder. It was suggested that further modifications are necessary to effectively reduce decoder complexity alongside encoder complexity.

In the context of constrained encoding, specific configurations achieved encoder complexity levels approximately twice that of the VTM encoder while maintaining comparable BD-rate gains. However, the decoding time exhibited significant variations, ranging from x2, x4, to even x6 the decoding time of the VTM decoder.

This contribution emphasizes the importance of illustrating both encoding and decoding times to provide a comprehensive understanding of trade-offs within the constrained encoding category. It is suggested that decoding time information be discussed jointly with encoding time, and this is beneficial for CfE response and practical implementation of the next generation of video coding standard.

It is proposed to also include an analysis of decoding runtime in the CfE part for fast encoding, as there is dependency of decoder and encoder runtime.

It was commented that in the analysis percentages of run time saving relative to anchor were averaged over the different rate points. It was suggested that an alternative could be averaging absolute run times (where the high rate points would usually require more, and saving is more relevant).