&lt;title&gt;Spatial-domain resolution-scalable video coding&lt;/title&gt;

Puri, Atul; Wong, Andria H.

doi:10.1117/12.157989

Cited by 22 publications

(3 citation statements)

References 2 publications

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“…In many applications, it is required to obtain an upsampled version of an image from its downsampled version. For example, for spatially scalable encoding of video [11], [12], a prediction of the original frame is obtained by upsampling the lower resolution frame and the difference is encoded in the enhancement or low-priority layer. We have seen that the downsampling scheme preserves all the low-frequency information of the original image.…”

Section: Upsamplingmentioning

confidence: 99%

A fast scheme for image size change in the compressed domain

Dugad

Ahuja

2001

IEEE Trans. Circuits Syst. Video Technol.

212

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Given a video frame in terms of its 8 8 block-DCT coefficients, we wish to obtain a downsized or upsized version of this frame also in terms of 8 8 block-DCT coefficients. The DCT being a linear unitary transform is distributive over matrix multiplication. This fact has been used for downsampling video frames in the DCT domain. However, this involves matrix multiplication with the DCT of the downsampling matrix. This multiplication can be costly enough to trade off any gains obtained by operating directly in the compressed domain. We propose an algorithm for downsampling and also upsampling in the compressed domain which is computationally much faster, produces visually sharper images, and gives significant improvements in PSNR (typically 4-dB better compared to bilinear interpolation). Specifically the downsampling method requires 1.25 multiplications and 1.25 additions per pixel of original image compared to 4.00 multiplications and 4.75 additions required by the method of Chang et al. Moreover, the downsampling and upsampling schemes combined together preserve all the low-frequency DCT coefficients of the original image. This implies tremendous savings for coding the difference between the original frame (unsampled image) and its prediction (the upsampled image). This is desirable for many applications based on scalable encoding of video. The method presented can also be used with transforms other than DCT, such as Hadamard or Fourier.

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Section: Upsamplingmentioning

confidence: 99%

A fast scheme for image size change in the compressed domain

Dugad

Ahuja

2001

IEEE Trans. Circuits Syst. Video Technol.

212

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“…An important exception to this rule can be found in MPEG-2's spatial scalability [13], H.263+ [22], MPEG-4 [24], where the enhancement predictor switches per macroblock between P1, P2, and a weighted linear combination of the two. However, linear combination remains an ad-hoc method of combining the two information sources and requires transmission of the weights as side-information.…”

Section: Problem and Motivationmentioning

confidence: 99%

“…Note that the estimate takes advantage of all sources of information available to the enhancement-layer. Note, further, that the best estimate is a nonlinear combination of the available information in contrast to the simple weighted average of P1 and P2 as in [13]. The enhancement-layer encoder quantizes the residual and transmits index .…”

Section: ) Base-layermentioning

confidence: 99%

Toward optimality in scalable predictive coding

Rose

Regunathan

2001

IEEE Trans. on Image Process.

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Abstract-A method is proposed for efficient scalability in predictive coding, which overcomes known fundamental shortcomings of the prediction loop at enhancement layers. The compression efficiency of an enhancement-layer is substantially improved by casting the design of its prediction module within an estimation-theoretic framework, and thereby exploiting all information available at that layer for the prediction of the signal, and encoding of the prediction error. While the most immediately important application is in video compression, the method is derived in a general setting and is applicable to any scalable predictive coder. Thus, the estimation-theoretic approach is first developed for basic DPCM compression and demonstrates the power of the technique in a simple setting that only involves straightforward prediction, scalar quantization, and entropy coding. Results for the scalable compression of first-order Gauss-Markov and Laplace-Markov signals illustrate the performance. A specific estimation algorithm is then developed for standard scalable DCT-based video coding. Simulation results show consistent and substantial performance gains due to optimal estimation at the enhancement-layers.

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MPEG-2 Scalability Techniques

Digital Video

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<title>Spatial-domain resolution-scalable video coding</title>

Cited by 22 publications

References 2 publications

A fast scheme for image size change in the compressed domain

A fast scheme for image size change in the compressed domain

Toward optimality in scalable predictive coding

MPEG-2 Scalability Techniques

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