JVET-AN0125 Non-EE2: On CABAC bin budget constraint [K.-Y. Kim, J.-H. Son, J.-Y. Kim, J.-S. Kwak (WILUS)]

This contribution proposes a solution to the issue of exceeding the bin budget limit. Specifically, the threshold for checking the remaining bin budget is increased from 4 to 8. Accordingly, before parsing any coefficients during regular residual coding, the decoder checks whether the number of remaining bin budget is less than 8 (instead of 4). The overall bin budget control mechanism remains unchanged. On top of ECM-18.0, the simulation results are reported as follows:

AI: {0.00%, 0.03%, 0.05%, 100.0%, 100.0%}

RA: {0.00%, 0.08%, 0.01%, 100.1%, 100.2%}

LDB: {-0.03%, 0.19%, 0.30%, 99.9%, 100.4%}

LDP: {0.01%, -0.16%, -0.09%, 100.0%, 100.4%}

The proposal proposes to change the interval of checking the remaining bin budget from 4 coefficients in ECM to 8 coefficients.

Cross checker reports matched results.

It was asked why the proposal, which practically reduces number of context coded bins, can achieve a small gai in LDB. The reason is unknown (perhaps small fluctuation).
It was commented that exactly the same modification had been proposed before, and no action was taken because nothing is broken. The small chance of exceeding context coded bins is irrelevant at this stage of the exploration.

No action at this moment.