Emerging ubiquitous multimedia services are expected to be available anytime, anywhere, and using different computing devices. video compression is necessary for transmission of digital video over today's band-lim...
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ISBN:
(纸本)9783540717881
Emerging ubiquitous multimedia services are expected to be available anytime, anywhere, and using different computing devices. video compression is necessary for transmission of digital video over today's band-limited networks, or for storage constrained applications. This paper gives a short overview over previous video coding standards and analyzes in more detail H.264, which is the latest international video coding standard. Since scalable videocoding (SVC) provides the capability of reconstructing lower resolution or lower quality signals from partial bitstream, it is a good paradigm to the streaming video application for ubiquitous multimedia service. Hence, we also discuss several coding techniques and frameworks for SVC including fine granular scalability (FGS).
In H.264 advanced video coding standard, the intra prediction made by referring to the surrounding coded pixels plays an important role in achieving the compression efficiency. To find the best prediction mode, the H....
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In H.264 advanced video coding standard, the intra prediction made by referring to the surrounding coded pixels plays an important role in achieving the compression efficiency. To find the best prediction mode, the H.264 reference software JM 6. 1 d suggests two criteria, the sum of absolute differences (SAD) and the sum of absolute transformed differences (SATD). The SATD criterion with extra Hadamard transform achieves better coding performance, but needs more computation than the SAD criterion. A fast algorithm is developed to reduce the computation of the SATD, by using the property of linear transform and the fixed-spatial relationship of predicted pixels in each intra mode. With the fast SATD computation, about 50% computation of the original SATD algorithm can be reduced. To further reduce the SATD computation, a two-stage simplified SATD method is proposed, which first uses the SAD criterion to eliminate some unwanted modes and then performs the fast SATD computation to select the best mode. Experimental results show that the proposed two-stage simplified SATD method can save about 70% of computation costs with negligible PSNR loss for H.264 intra prediction.
This paper presents an innovative algorithm for detecting all-zero discrete cosine transform (DCT) coefficient blocks prior to DCT and quantization for all block-based video coding standards. A mathematic model is est...
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This paper presents an innovative algorithm for detecting all-zero discrete cosine transform (DCT) coefficient blocks prior to DCT and quantization for all block-based video coding standards. A mathematic model is established based on analyzing DCT coefficient distribution and applying Paseval energy conservation theorem. The algorithm is applied to H.264 videocoding and experimental results show up to 32% higher detection ratio without degrading video quality, compared with results of the existing methods. Furthermore, up to 47% higher detection ratio is achieved by changing the threshold based on DCT coefficient distribution. For motion estimation, much less search points needed by using the proposed method as early termination criterion than that by using the existing methods.
Motion estimation plays an important role in video compression systems, and it's the most intensively computational and the most time-consuming part at the same time. So it could significantly affect the operation...
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ISBN:
(纸本)0819460583
Motion estimation plays an important role in video compression systems, and it's the most intensively computational and the most time-consuming part at the same time. So it could significantly affect the operation efficiency of whole videocoding systems and the reconstructed quality of video sequence. The latest video coding standard, H.264, provides a significant coding efficiency than previous standards. But this coding gain comes at the cost of a very computationally-intensive motion estimation module. To realize the implementation of the H.264 videocoding in-time, it's desirable to develop fast motion search algorithm. In order to reduce computation complexity of the motion search at sub-pixel accuracy, a fast and effective search algorithm for half-pixel motion estimation is proposed in this paper. Based on the single valley characteristic of half-pixel error matching function inside search grid, half-pixel candidate points needing checking are predicted with the help of comparison results of SAD values for four integer-pixel points around integer-pixel motion vector, so a great number of computations associated with search process are avoided. The experimental results reveal that, to all kinds of video sequences, the proposed algorithm can obtain almost the same video quality as that of the half-pixel full search algorithm with reduced average 72% computation cost.
The H.264/MPEG-4 AVC is the video coding standard which achieves much higher coding efficiency than previous standards such as H.263 or MPEG4. The improvement in the rate-distortion performance of the H.264 is mainly ...
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ISBN:
(纸本)0780393953
The H.264/MPEG-4 AVC is the video coding standard which achieves much higher coding efficiency than previous standards such as H.263 or MPEG4. The improvement in the rate-distortion performance of the H.264 is mainly due to the accurate motion estimation with multiple block sizes and multiple reference frames. However, this performance gain comes at the cost of a greatly increased computational complexity. In this paper, a very fast mode decision algorithm is proposed for H.264 videocoding, which can enables the H.264 encoder to be effectively adopted for video communications and mobile implementations. Simulation results show that the proposed algorithm can efficiently reduce the encoding time by 85% with similar visual quality and bit rate.
Conventional videocoding techniques make use of the most recently decoded reference frame(s) for motion-compensated inter prediction. However, it has been shown that to allow using reference frames in a flexible way ...
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ISBN:
(纸本)0819459763
Conventional videocoding techniques make use of the most recently decoded reference frame(s) for motion-compensated inter prediction. However, it has been shown that to allow using reference frames in a flexible way such that not only the latest reference frames are used is beneficial. A typical use of flexible reference frame is feedback based reference picture selection, wherein error-free reference frames available in both the encoder and decoder sides are selected and used for inter prediction reference. This paper first overviews support of reference picture selection in different video coding standards, and then presents three specific feedback based reference picture selection methods using flexible reference frames. In addition, a novel simple reference frame management method that enables using of flexible reference frame is proposed. The reference frame management method enables much simpler video codec implementations compared to the complex reference frame management methods in H.263 Annex U and H.264/AVC. The proposed coding methods and some conventional methods are compared with each other. Simulation results show significantly improved error resiliency performance of the proposed reference picture selection methods compared to conventional methods. The effect on the performance imposed by feedback delay variation is also shown. Thanks to the merits, support of flexible reference frame and the reference frame management has been adopted to the AVS-M video coding standard.
In this paper,we present a new method to enhance image quality at face region of head and shoulder type image sequence and to shorten processing latency to achieve synchronization between lip movement and voice (lip s...
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In this paper,we present a new method to enhance image quality at face region of head and shoulder type image sequence and to shorten processing latency to achieve synchronization between lip movement and voice (lip sync).The new method can significantly improve image quality at face region and reduce frame skip operation during high movement image coding. Improvement is done by allocating more bits budget to the face region,where the center of perceptual interest point usually *** number of bits of dynamically change background region is compressed by applying temporal filter to suppress background *** design a new fast rate control based on non-zero coefficient evaluation to shorten compression *** experimental result shows the increment of face region's PSNR by around 2 dB,the decreasing of skipping operation around 60 frames during encoding of 382 frames of highly movement video sequence and the advantage of having a very small compression latency around 3 frames which can resolve the lips sync problem.
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