Block effect is one of the most annoying artifacts in digital video processing and is especially visible in low-bitrate
applications, such as mobile video. To alleviate this problem, we propose an adaptive quantization method for inter
frames that can reduce visible block effect in DCT-based video coding. In the proposed method, a set of quantization
matrices are constructed before processing the video data. Matrices are constructed by exploiting the temporal frequency
limitations of human visual system. The method is adaptive to motion information and is able to select an appropriate
quantization matrix for each inter-coded block. Based on the experimental results, the proposed scheme can achieve
better subjective video quality compared to conventional flat quantization especially at low-bitrate application.
Moreover, it does not introduce extra computational cost in software implementation. This method does not change
standard bitstream syntax, so it can be directly applied to many DCT-based video codecs. A potential application could
be for mobile phone and other digital devices with low-bitrate requirement.