Block-layer optimal bit allocation based on constant perceptual quality

Wang, Chao; Mou, Xuanqin; Zhang, Lei

doi:10.1117/12.908109

Cited by 4 publications

(4 citation statements)

References 7 publications

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“…The reason for choosing the size of 4x4 MBs is because such size areas can contain enough structure information for perceptual quality measure, and are of local enough at the same time. The 4x4 MB sized areas have been used in the constant perceptual quality based bit allocation methods in [8], which achieves good encoding performance.…”

Section: Model Accuracy For Local Areas Inside a Framementioning

confidence: 99%

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A perceptual quality based rate distortion model

Wang

Mou

Zhang

2012

2012 Fourth International Workshop on Quality of Multimedia Experience

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Rate and distortion models (R-D models) are important for current image/video encoders. They can help encoders to find the best encoding parameters for improving encoding performance quickly and effectively. However, most of the existing R-D models are based on mean square error (MSE). For the purpose of achieving better perceptual quality in encoding, the R-D models based on perceptual distortion measurement are involuntarily needed. In this paper, we proposed a perceptual quality based R-D model for lossy image/video encoding. The experimental results show that, the proposed model can accurately describe the R-D characteristics of the sources in the context of perceptual distortion, both for whole frames and the areas inside frame.Index Terms-Rate distortion model, perceptual quality metrics, lossy encoding.

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Section: Model Accuracy For Local Areas Inside a Framementioning

confidence: 99%

“…There have been a lot of works to pursue this goal [4][5][6][7][8]. Among them, two perceptual quality metric based R-D models have been presented.…”

Section: Introductionmentioning

confidence: 99%

A perceptual quality based rate distortion model

Wang

Mou

Zhang

2012

2012 Fourth International Workshop on Quality of Multimedia Experience

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“…The work of [5] has shown that the CPQ based block-layer bit allocation can help to release more bits. In that work, it showed an encoder for intra frame encoding, which optimized the bit allocation by minimizing the perceptual quality fluctuation among "local areas" over whole frame, had achieved attractive performance.…”

Section: Introductionmentioning

confidence: 99%

Block-layer bit allocation for quality constrained video encoding based on constant perceptual quality

et al. 2013

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In lossy image/video encoding, there is a compromise between the number of bits (rate) and the extent of distortion. Bits need to be properly allocated to different sources, such as frames and macro blocks (MBs). Since the human eyes are more sensitive to the difference than the absolute value of signals, the MINMAX criterion suggests to minimizing the maximum distortion of the sources to limit quality fluctuation. There are many works aimed to such constant quality encoding, however, almost all of them focus on the frame layer bit allocation, and use PSNR as the quality index. We suggest that the bit allocation for MBs should also be constrained in the constant quality, and furthermore, perceptual quality indices should be used instead of PSNR. Based on this idea, we propose a multi-pass block-layer bit allocation scheme for quality constrained encoding. The experimental results show that the proposed method can achieve much better encoding performance.

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“…There are already many works that use IQA metrics in video encoding and achieves promising results [10], [24]- [28]. Our previous works have shown the advantage of using IQA metrics in intra-frame constant quality encoding [29]- [31]. In this paper, we propose an CPQ-based method for the bit allocation of intra-frames in H.264/AVC.…”

Section: Introductionmentioning

confidence: 99%

QP Selection Optimization for Intra-Frame Encoding Based on Constant Perceptual Quality

Wang

Mou

Zhang

2016

IEICE Trans. Inf. & Syst.

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SUMMARYIn lossy image/video encoding, there is a compromise between the number of bits and the extent of distortion. Optimizing the allocation of bits to different sources, such as frames or blocks, can improve the encoding performance. In intra-frame encoding, due to the dependency among macro blocks (MBs) introduced by intra prediction, the optimization of bit allocation to the MBs usually has high complexity. So far, no practical optimal bit allocation methods for intra-frame encoding exist, and the commonly used method for intra-frame encoding is the fixed-QP method. We suggest that the QP selection inside an image/a frame can be optimized by aiming at the constant perceptual quality (CPQ). We proposed an iteration-based bit allocation scheme for H.264/AVC intra-frame encoding, in which all the local areas (which is defined by a group of MBs (GOMBs) in this paper) in the frame are encoded to have approximately the same perceptual quality. The SSIM index is used to measure the perceptual quality of the GOMBs. The experimental results show that the encoding performance on intra-frames can be improved greatly by the proposed method compared with the fixed-QP method. Furthermore, we show that the optimization on the intra-frame can bring benefits to the whole sequence encoding, since a better reference frame can improve the encoding of the subsequent frames. The proposed method has acceptable encoding complexity for offline applications.

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Block-layer optimal bit allocation based on constant perceptual quality

Cited by 4 publications

References 7 publications

A perceptual quality based rate distortion model

A perceptual quality based rate distortion model

Block-layer bit allocation for quality constrained video encoding based on constant perceptual quality

QP Selection Optimization for Intra-Frame Encoding Based on Constant Perceptual Quality

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