Perceptual Effects of Noise in Digital Video Compression

Published

March 1, 2000

Author(s)

Charles D. Fenimore, John M. Libert, S. A. Wolf

Abstract

This paper presents the results of subjective viewer assessment of the quality of MPEG-2 compressed video containing wideband Gaussian noise. The video test sequences consisted of seven test clips (both classical and new materials) to which noise with a peak signal-to-noise ratio (PSNR) of 28 to 47 dB was added. Software encoding and decoding was performed at five-bit rates ranging from 1.8 to 13.9 Mbits/sec. A panel of 32 viewers rated the difference between the noisy input and the compression-processed output. For low noise levels, the subjective data suggests that compression at higher bit-rates can actually improve the quality of the output, effectively acting as a low-pass filter. Defining an objective and a subjective measure of scene criticality allows finding the two measures that correlate for the data. For difficult-to-encode material (high criticality), the data suggests that the effects of compression may be less noticeable at mid-level noise. In contrast, for easy-to-encode video (low criticality), the addition of a moderate amount of noise to the input led to lower quality scores. This suggests that either the compression process may have reduced noise impairments or a form of masking may occur in scenes that have high levels of spatial detail.

Citation

Smpte Journal

Volume

109

Issue

3

Pub Type

Journals

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Keywords

digital video compression, noise, objective, subjective quality measurement

Citation

Fenimore, C. , Libert, J. and Wolf, S. (2000), Perceptual Effects of Noise in Digital Video Compression, Smpte Journal, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=28839 (Accessed January 2, 2025)