Cross-dimensional quality assessment for low bitrate video

In this paper, we address the problem of evaluating perceptual visual quality of compressed video under different settings for mobile communication. A 5-dimensional video feature space is constructed with the codec type, video content, frame size, frame rate and bitrate. The video quality assessment is formulated as a transformation between the multidimensional feature space and the quality space. Subject viewing tests for videos coded with H.263 and H.264 at different bitrates and spatial/temporal resolutions are performed. Based on statistical analysis, we find that the perceptual quality of the decoded video is affected by the encoder type, video content, bitrate, frame rate and frame size, in a descending order for significance. The methodology and findings in this paper designate new researching direction in video quality assessment and can be extended to other applications.