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)
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)
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)
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)
DCT-based CODECs such as MPEG-4 Visual and H.263 " skip " many macroblocks during encoding of typical video sequences (i.e. no coded data is transmitted for these macroblocks). This paper describes an algorithm that predicts macroblocks that are likely to be skipped by the encoder. The algorithm estimates the increase in distortion due to not coding(More)
The multimedia capability of video telephony and video conferencing systems has many applications and benefits. This paper describes research and development that aims to optimise video compression systems for a specific application - personal communication at a distance for deaf people. Results of eye movement tracking experiments and proposals for image(More)