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This work investigates the impact of non-periodic quantization step size variation on perceptual video quality. We composed non-periodic temporal variation patterns from periodic variation patterns. We present subjective test results and examine how does the overall quality under non-periodic variation relate to the qualities of individual periodic components, and how does it relate to the instantaneous...
This work investigates the impact of temporal variation of quantization stepsize (QS) on perceptual video quality. Among many dimensions of QS variation, as a first step we focus on videos in which two QS's, alternate over fixed intervals. We present subjective test results, and analyze the influence of several factors (including the QS difference, QS ratio, changing intervals, and video content)...
In this paper, we investigate the impact of spatial, temporal and amplitude resolution (STAR) on the perceptual quality of a compressed video. Subjective quality tests were carried out on the TI Zoom2 mobile development platform (MDP). Seven source sequences are included in the tests and for each source sequence we have 32 test configurations generated by JSVM encoder (4 QP levels, 5 spatial resolutions,...
In networked video applications where the sustainable bandwidths vary greatly among the receivers and in time, one must be able to code a video or adapt a precoded-bitstream to a wide range of bit rates. It is critical to choose appropriate frame size, frame rate and quantization stepsize (QS) to optimize the perceptual quality for a target bit rate. Furthermore, it is important to understand the...
This work investigates the impact of periodic frame rate variation on perceptual video quality. Among many dimensions of frame rate variation, as a first step we focus on videos in which two frame rates alternate over fixed intervals. We present subjective test results, and analyze the influence of several factors (including the average frame rate, the frame rate deviation, and the video content)...
This paper investigates the perceptual quality of video affected by packet losses. We focus on low-resolution and low bit-rate video coded by the H.264/AVC encoder and the packet loss patterns likely in low bit-rate wireless networks. We examine the impact of several factors on the perceptual quality, including the error length (the error propagation duration after a loss), the loss severity (measured...
This study aims to understand how perceived quality of a video varies as the frame rate changes. We find that an inverted falling exponential function can accurately reflect the trend observed from subjective testing. We further explore the relationship between the falling rate and the video content features, such as frame difference, motion, and contrast.
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