HVS-based quantization steps for validation of digital cinema extended bitrates

Larabi, C [Université de Poitiers] Anciaux, G [Université de Poitiers] Tulet, O [Université de Poitiers] Fernandez, C [Université de Poitiers] Macq, Benoît [UCL] Devaux, F-O [UCL] PELLEGRIN, Pascal [UCL]

In Digital Cinema, the video compression must be as transparent as possible to provide the best image quality to the audience. The goal of compression is to simplify transport, storing, distribution and projection of films. For all those tasks, equipments need to be developed. It is thus mandatory to reduce the complexity of the equipments by imposing limitations in the specifications. In this sense, the DCI has fixed the maximum bitrate for a compressed stream to 250 Mbps independently from the input format (4K/24fps, 2K/48fps or 2K/24fps). The work described in this paper This parameter is discussed in this paper because it is not consistent to double/quadruple the input rate without increasing the output rate. The work presented in this paper is intended to define quantization steps ensuring the visually lossless compression. Two steps are followed first to evaluate the effect of each subband separately and then to fin the scaling ratio. The obtained results show that it is necessary to increase the bitrate limit for cinema material in order to achieve the visually lossless.