Iain E. Garden Richardson

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—A complexity reduction algorithm for an H.264 encoder is proposed. Computational savings are achieved by identifying, prior to motion estimation, macroblocks that are likely to be skipped and hence saving further computational processing of these macroblocks. This early prediction is made by estimating a Lagrangian rate-distortion cost function which(More)
Video communication systems for deaf people are limited in terms of quality and performance. Analysis of visual attention mechanisms for sign language may enable optimization of video coding systems for deaf users. Eye-movement tracking experiments were conducted with profoundly deaf volunteers while watching sign language video clips. Deaf people are found(More)
This paper presents a new video quality metric for automatically estimating the perceptual quality of compressed video sequences. Distortion measures such as the mean squared error (MSE) and the peak signal to noise ratio (PSNR) have been found to poorly correlate with visual quality at lower bit-rates. The proposed quality metric (MOSp) predicts perceptual(More)
Variable-complexity algorithms provide a means of managing the computational complexity of a software video CODEC. The reduction in computational complexity provided by existing variable-complexity algorithms depends on the video scene characteristics and is difficult to predict. A new approach to variable-complexity encoding is proposed in this paper. A(More)
I n this paper, we investigate methods of reducing the computational complexity of the discrete cosine transform (DCT) in a software video encoder. The number of DCT calculations may be reduced by modeling the distribution of zero blocks. We demonstrate that the reduction in computational complexity is variable and depends on the statistics of the video(More)
Topic area: image and video processing and analysis / image and video coding Abstract. The influences of task and scene content on a viewer's subjective opinion of compressed video quality are investigated. A group of test subjects are presented with a number of compressed video clips, with or without an initial " task " instruction. Subjective quality(More)
Modern video compression systems make optimum coding decisions based on rate-distortion performance. Typically the distortion is evaluated as a mathematical error measurement, such as mean squared error (MSE), between the original and compressed video sequences. However, simple automatic error measurements such as MSE do not correlate well with perceptual(More)