Flickering is a temporal visual artifact that affects compressed video. It is prominent in intra-frame video coders and is largely the result of content variations and quantization. We concentrate on flickering due to quantization. JPEG2000 uses Post-Compression Quantization which is applied through the EBCOT algorithm. EBCOT has been found, however, to cause significant flickering in the reconstructed video. In this work, we evaluate existing flicker metrics, investigate the causes of flicker, and propose a new rate-distortion optimal algorithm that suppresses flicker. The proposed algorithm suppresses temporal flicker at a negligible cost in spatial image quality.