Perceptual Effects of Noise in Digital Video Compression

Published

October 1, 1998

Author(s)

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

Abstract

We present results of subjective viewer assessment of video quality of MPEG-2 compressed video containing wide-band Gaussian noise. The video test sequences consisted of 7 test clips (both classical and new materials) to which noise with a peak-signal-to-noise-ratio (PSNR) from 28 dB to 47 dB was added. We used software encoding and decoding at five-bit rates ranging from 1.8 Mb/s to 13.9 Mb/s. Our 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 like a low-pass filter. We define an objective and a subjective measure of scene criticality (the difficulty of compressing a clip) and find the two measures correlate for our data. For difficult-to-encode material (high criticality), the data suggest that the effects of compression may be less noticeable at mid-level noise, while 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.

Proceedings Title

Proc. 140th SMPTE Technical Conf.- DTV Reality Check -- The First Year

Volume

109

Issue

3

Conference Dates

October 28-31, 1998

Conference Location

Pasadena, CA

Pub Type

Conferences

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Keywords

digital video compression, noise, objective, subjective quality measurement, digital video compression, noise, objective, subjective quality measurement

Citation

Fenimore, C. , Libert, J. and Wolf, S. (1998), Perceptual Effects of Noise in Digital Video Compression, Proc. 140th SMPTE Technical Conf.- DTV Reality Check -- The First Year, Pasadena, CA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=18713 (Accessed July 17, 2024)