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

IEICE Trans. Inf. & Syst.

2015

Self Cite

SUMMARYIn this letter, we study the R-D properties of independent sources based on MSE and SSIM, and compare the bit allocation performance under the MINAVE and MINMAX criteria in video encoding. The results show that MINMAX has similar results in terms of average distortion with MINAVE by using SSIM, which illustrates the consistency between these two criteria in independent perceptual video coding. Further more, MINMAX results in lower quality fluctuation, which shows its advantage for perceptual video coding. key words: optimal bit allocation, MINAVE, MINMAX, perceptual video coding

Section: Introductionmentioning

confidence: 79%

A Study on Consistency between MINAVE and MINMAX in SSIM Based Independent Perceptual Video Coding

Wang

IEICE Trans. Inf. & Syst.

2015

Self Cite

“…This largely restricts its applications in designing image processing algorithms such as image compression and restoration. Recently, some works [36][37][38] have been reported to adopt SSIM for image/video perceptual compression. However, these methods are not "one-pass" and they have high complexity.…”

Section: G Discussionmentioning

confidence: 99%

Gradient Magnitude Similarity Deviation: A Highly Efficient Perceptual Image Quality Index

Xue

IEEE Trans. on Image Process.

et al. 2014

Self Cite

1,329

644

Abstract-It is an important task to faithfully evaluate the perceptual quality of output images in many applications such as image compression, image restoration and multimedia streaming. A good image quality assessment (IQA) model should not only deliver high quality prediction accuracy but also be computationally efficient. The efficiency of IQA metrics is becoming particularly important due to the increasing proliferation of high-volume visual data in high-speed networks. We present a new effective and efficient IQA model, called gradient magnitude similarity deviation (GMSD). The image gradients are sensitive to image distortions, while different local structures in a distorted image suffer different degrees of degradations. This motivates us to explore the use of global variation of gradient based local quality map for overall image quality prediction. We find that the pixel-wise gradient magnitude similarity (GMS) between the reference and distorted images combined with a novel pooling strategy -the standard deviation of the GMS map -can predict accurately perceptual image quality. The resulting GMSD algorithm is much faster than most state-of-the-art IQA methods, and delivers highly competitive prediction accuracy. MATLAB source code of GMSD can be downloaded at http://www4.comp.polyu.edu.hk/~cslzhang/IQA/ GMSD/GMSD.htm.Index Terms-Gradient magnitude similarity, image quality assessment, standard deviation pooling, full reference

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

Wang

IEICE Trans. Inf. & Syst.

2016

Self Cite

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.