A new algorithm of speech coding "recursive and adaptive prediction" is proposed and tested. An adaptive linear prediction of the input is carried out sample by sample, and only predictive residuals are quan...
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A new algorithm of speech coding "recursive and adaptive prediction" is proposed and tested. An adaptive linear prediction of the input is carried out sample by sample, and only predictive residuals are quantized and transmitted in binary codes. predictive coefficients are adaptively controlled by quantized prediction error. Segmental SNR of almost 22 dB is obtained at 16 kb/s by the cascade connection of 2 stages of prediction. The algorithm can handle mixed voices and be implemented by single DSP.
It has been asserted that temporal subband coding (TSB) is inferior to predictive coding for regionally motion compensated (e.g. block-based MC) temporally scalable compressed video. There are two major disadvantages ...
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It has been asserted that temporal subband coding (TSB) is inferior to predictive coding for regionally motion compensated (e.g. block-based MC) temporally scalable compressed video. There are two major disadvantages of TSB coding: temporal filtering distortions, and 'open-loop' predictive coding of covered and uncovered regions. The 'open-loop' structure of TSB coding, however, affords two major advantages not enjoyed by MCP coding: simple optimal bit-allocation, non-existence of quantization error feedback. A new adaptive temporal subband (TSB) motion compensated predictive (MCP) coder is proposed. Hierarchical variable-sized block-matched regions with low predictive error are TSB coded, while poorly predicted regions are 'open-loop' MCP coded. Simulation results demonstrate that the adaptive coder substantially improves the temporal scalability of TSB coding, retains an advantageous 'open-loop' structure and provides comparable or superior PSNR to both MCP and TSB coding at MPEG-1 quality bitrates.
We present a novel multi-resolution block matching algorithm (BMA) for fast motion estimation. At the coarsest level, a full search BMA (FSBMA) is performed for searching complex or random motion. Concurrently, spatia...
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ISBN:
(纸本)0780350413
We present a novel multi-resolution block matching algorithm (BMA) for fast motion estimation. At the coarsest level, a full search BMA (FSBMA) is performed for searching complex or random motion. Concurrently, spatial correlation of motion vector (MV) field is used for searching continuous motion. Here we present an efficient method for searching full resolution MVs without MV decimation even at the coarsest level. After the coarsest level search, two or three initial MV candidates are chosen for the next level. At the further levels, the MV candidates are refined within much smaller search areas. Simulation results show that in comparison with FSBMA, the proposed BMA achieves a speed-up factor over 710 with minor PSNR degradation of 0.2 dB at most, under a normal MPEG-2 coding environment. Furthermore, our scheme is also suitable for hardware implementation due to regular data-flow.
This paper describes an execution unit capable of computing the Paeth predictor, as used in the portable network graphics (PNG) standard. PNG is a rather new, lossless compression method for real-world pictures. It fe...
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This paper describes an execution unit capable of computing the Paeth predictor, as used in the portable network graphics (PNG) standard. PNG is a rather new, lossless compression method for real-world pictures. It features five prediction schemes, of which the modified Paeth predictor is the most computational intensive. This paper focuses on a hardware implementation of the Paeth predictor and a hardware Paeth codec capable of computing three different quantities: the Paeth predictor of three inputs, the difference of the current pixel and the Paeth predictor of the other inputs (coding), and the sum of the coded input and the Paeth predictor of the other three inputs (decoding). The proposed Paeth codec takes two cycles, where a cycle is comparable to an general purpose ALU cycle. Depending on the mode of operation, the proposed mechanism produces the predictor or the (de/en)-coded pixel value.
This paper describes new statistical models of the JPEG lossless mode subject to the super high definition images (SHDI). Seven predictors prepared in the JPEG are very simple to alleviate the complexity of the predic...
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This paper describes new statistical models of the JPEG lossless mode subject to the super high definition images (SHDI). Seven predictors prepared in the JPEG are very simple to alleviate the complexity of the prediction process, which indicates that prediction residuals correlate. The actual correlation of the residuals exhibits a tendency to be more significant as the number of picture elements increases. Consequently, the conditional probability densities of the residual signals for SHDI differ from the Laplacian distribution commonly assumed in predictive coding. We propose two statistical models considering the peculiar probability densities and investigate the validity of the models by coding simulations.
In video communication systems based on motion-compensated predictive coding, transmission errors cause spatial and temporal distortion propagation during; the reconstruction of the video sequence at the receiver. Two...
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In video communication systems based on motion-compensated predictive coding, transmission errors cause spatial and temporal distortion propagation during; the reconstruction of the video sequence at the receiver. Two commonly used techniques to stop error propagation are (1) periodic refreshing by intra-frame coding and (2) retransmission. However, frequent intra-frame refreshing may be expensive in band-limited applications such as wireless video transmission. On the other hand, retransmission causes additional delay which may be intolerable in real-time applications. We present a novel video coding mode which we call transmitter receiver identical reference frame (TRIRF) based inter-frame coding. Under the assumption of the existence of a feedback channel, TRIRF-frame coding constructs a new type of reference frame from the correctly received data which is made identical both at the receiver and the transmitter. Motion estimation and compensation are based on the TRIRF-frame. Simulations show that TRIRF-frame coding prevents error propagation as effectively as intra-coding but with improve compression efficiency. We also propose a packetization scheme for the encoded video bit streams which enables rapid resynchronization of the decoder.
In this paper, a new fast block matching algorithm is developed for motion estimation. The feature of the new algorithm comes from the center-biased checking concept and the trend of pixel movements. In this algorithm...
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In this paper, a new fast block matching algorithm is developed for motion estimation. The feature of the new algorithm comes from the center-biased checking concept and the trend of pixel movements. In this algorithm, we develop two criteria for the searching algorithm to be adapted to local characteristics of the test block. Simulation results show that the total search positions are about 20% fewer than TSS while the MSE performance is better than TSS and very close to the full search method.
This paper presents a method for designing and optimizing predictive vector quantizers (PVQ) for coding the line spectral frequencies (LSF) in LPC-based speech and audio coders. The algorithm is based on iterative opt...
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This paper presents a method for designing and optimizing predictive vector quantizers (PVQ) for coding the line spectral frequencies (LSF) in LPC-based speech and audio coders. The algorithm is based on iterative optimization of the predictors and the vector-quantizer codebooks. It is shown that the proposed method yields high quality LSF predictive quantizers with performance exceeding that of the PVQ used in the G.729 standard.
In this paper, we present a VQ-based two-codebook design which uses separate codebooks for predicted residuals and full pixel values. We show that our approach captures abrupt scene changes while exploiting inter-fram...
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In this paper, we present a VQ-based two-codebook design which uses separate codebooks for predicted residuals and full pixel values. We show that our approach captures abrupt scene changes while exploiting inter-frame dependencies. We use a simple universal code consisting of two codebooks, an intra-codebook containing codewords that are used as reproduction of image blocks together with a residual-codebook. Codebooks are selected to minimize distortion for the block being coded. If there is relatively little motion in a frame, most blocks use the residual-codebook. On the other hand, if a frame is very different from the previous one, most blocks will be coded using the intra-codebook. When compared to other VQ schemes mentioned above, the resulting quantizer not only follows scene changes closely with satisfactory fidelity but also is robust against mismatch between the training and test sequence. We compare the PSNR of three coding schemes, intra-coding-only, inter-coding only, and the proposed method.
Linear predictive techniques perform poorly when used with color-mapped images where pixel values represent indices that point to color values in a look-up table, Reordering the color table, however, can lead to a low...
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Linear predictive techniques perform poorly when used with color-mapped images where pixel values represent indices that point to color values in a look-up table, Reordering the color table, however, can lead to a lower entropy of prediction errors, In this paper, we investigate the problem of ordering the color table such that the absolute sum of prediction errors is minimized, The problem turns out to be intractable, even for the simple case of one-dimensional (1-D) prediction schemes, We give two heuristic solutions for the problem and use them for ordering the color table prior to encoding the image by lossless predictive techniques. We demonstrate that significant improvements in actual bit rates can be achieved over dictionary-based coding schemes that are commonly employed for color-mapped images.
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