JVET-C0066 On Coefficient Scaling [D. B. Sansli, D. Rusanovskyy, J. Sole, A. K. Ramasubramonian, M. Karczewicz (Qualcomm)]

This contribution proposes an alternative to the residual scaling proposed in JVET-B0054. The motivation in JVET-B0054 is to remove the overhead of delta QP that is signalled by the encoder to compensate for the reshaping of quantization noise as a function of brightness in containers such as ST 2084. This is done by adapting the scaling of AC coefficients based on the DC coefficient and reconstructed prediction mean. In the proposal, a scale determination method is modified to allow the scaling of all coefficients equally, and the scaling operation is moved after the dequantization operation in the decoder for a simpler design. Simulations were conducted using HDR/WCG sequences from JCT-VC. Random access configuration with 64x64 CTU size reportedly showed an average of 2.5 % BD-rate gain for delta-E.

What would be the benefit compared to EE4/JVET-B0054? This was not possible to assess, since the contributors of C0066 found a mismatch in the EE4 software.

Further study of C0066 was requested in an AHG on JEM coding of extended colour volume material.