• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.744-752
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• 2005

When the multiple video sources are transmitted together through the channel of fixed bandwidth, an efficient picture quality control is necessary. This paper presents a joint picture quality control method to satisfy the user requirement by priority among the video sources. The better picture quality is assigned to the source of higher priority compared to lower priority. We obtain the bitrate for each source to have a required distortion level among the sources by using an approximate distortion-bitrate model for simple implementation. It is shown by simulation that the proposed bandwidth allocation method can keep almost the user-required picture quality among the sources in comparison to an independent bandwidth allocation method.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.84-90
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• 1997

We proposed a new bit-rate control algorithm to improve MPEG-2 video software encoder. Bit-rate Control plays an improtant role in picture quality of MPEG-2 encoder. To achieve better encoding performance such as controlling picture quality and using bity properly, we proposed a MPEG-2 bit-rate control algorithm using linear average Step-Size. Using a benchmark Program, we compared our algorithm with MPEG-2 Test Model 5. Our proposed algorithm showed better Bit-Rate Control with respect to used bits, picture quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.130-136
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• 2002

It is required to control the picture quality among video sources when the multiple video sources are together transmitted through the channel of fried bandwidth such as satellite and terrestrial broadcasting. This paper presents a control method to keep the uniform picture quality among the video sources. We first find a model of distortion and titrate far the multiplexing system of multiple sources. Then we allocate the bitrate to each source for uniformly divided picture quality among the sources by using the distortion-bitrate relationship for the real-time implementation without time delay. It is shown by simulation that the proposed quality control method can keep almost uniform picture quality among the sources in comparison to the conventional control method.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.316-321
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• 2001

When the multiple video sources are together transmitted through the channel of fixed bandwidth, the efficiently picture quality method is necessary. This paper presents the picture quality control method to keep the same distortion level among the video sources. We first find a model of distortion and bitrate for the multiplexing system of multiple sources. Then we obtain the bitrate for each source to have same distortion level among the sources by using the approximated model parameters for simple implementation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.187-190
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• 1997

Test Model15, which is used widely for the MPEG-2 bit rate control, has several problems such as non-unform picture quality, scene change and buffer underflow. Therefore, various algorithms have been developed to solve these problems. In this paper, we study various algorithms for the MPEG-2 bit rate control and compare their performances using software simulations. We also propose a new bit rate control strategy based on coded types of macroblocks within a picture.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.149-152
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• 2011

A Multi-Vision needs an image adjust of each product to make the same picture quality for all products when it's installed. Owing to this reason need individual control. This document request indivisual control method for each product with the Remote controller. To realize this method need make Set ID and Picture ID on the UI and need daisy chain of cable to connect Remocon code(IR Signal) In to Out, After allocation the Set ID for each product. Picture ID of the product which want to change picture quality make equal to Set ID. And the product which is same Set ID and Picture ID is only controlled through decoding of Remocon code to Scaler.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2010-2024
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• 1998

In video coding, it is important to improve the average picture quality as well as to maintain cosistent picture quality between consecutive pictures. In this paper, we propose a distortion-rate estimation method for MPEG-2 video and a forward rate control method, using the proposed estimation result, to be able to obtain the improved and consistent picture quality of CBR (Constant Bit Rate) encoded MPEG-2 video. The proposed distortion-rate estimation enable us to predict the distortion and the bits generated from an encoded picture at a given quantization step size and vice versa. The most attactive features of proposed distortion-rate estimation are its accuracy and low computational complexity enough to be applied to the practical video coding. In addition, the proposed rate control first determined a quantization parameter per frame by following procedure: distortion-rate estimation, target bit allocation, distortion constraint and VBV(Video Buffer Verification) constraint. And then this quantization parameter is applied to the encoding so that improved and consisten picture quality can be obtained. Furthermore the proposed rate control method can solve the error propagation problem caused by scene change or anchor picture degradation by using the B-picture skipping and the guarantee of the minimum bit allocation for the anchor picture. Experimental results, comparing the proposed forward rate control method with TM5 method, show that the proposed method makes more improed and consistent picture quality than TM5.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.670-675
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• 2012

If the region of interest (ROI) is set within the picture of image and video and the high quality is provided in ROI compared to Non ROI, then overall subjective picture quality can be increased. ROI extracted by the color camera only increases the calculation complexity and reduces the extraction accuracy. In this paper, we use depth camera to set the ROI and calculate the object distance from camera, then propose a method that the different picture quality is controlled by depending on the distance of an object. That is, we apply a high quantization step size to the far object, but relatively a low quantization step size to the close object, so better picture quality can be provided. Simulation results show that applying the differential quantization step size to the distance of objects by the proposed method can improve the subjective picture quality.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.591-596
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• 1999

In this paper, we present a joint quality control system to be able to accurately control the relative picture quality among the video programs in terms of PSNR. The joint quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determined relative picture quality among the aggregated video programs while keeping a constant sum of the bit rates for all programs to be transmitted over a single constant bit rate (CBR) channel. This is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. Furthermore we also suggest buffer regulation method based on the analysis of the constraints imposed by sender/receiver buffer sizes and total transmission rate. Through various simulation results, it is found that our quality control systems guarantee that the video buffers do not overflow and underflow and the quality control errors do not exceed 0.1 ㏈.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.69-84
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• 1998

In digital broadcasting, services such as digital satellite TV, cable TV and digital terrestrial TV, several video programs are compressed by MPEG-2, and then simultaneously transmitted over a conventional CBR (Constant Bit Rate) broadcasting channel. In this paper, we propose a joint quality control scheme to be able to accurately control the relative picture quality among the video programs, which is achieved by simdt;,nL'Ously controlling the video encoders to generate the VBR (Variable Bit Rate) compressed video streams. Our quality control scheme can prevent the video buffer overflow and underflow by total target bit allocation process, and also exactly control the relative picture quality in terms of PSNR (Peak Signal to Noise Ratio) between some programs requiring higher picture quality and others by rate-distortion modification. Furthermore we present a rate-distortion estimation method for MPEG-2 video, which is base of our joint quality control, and verify its performance by experiments. The most attractive features of this estimation method are as follows: 1) computational complexity is low because main operation for the estimation is to calculate the histogram of OCT coefficients into quantizer; 2) estimation results are very accurate enough to be applied to the practical MPEG-2 video coding applications. Simulation results show that the proposed joint quality control scheme accurately controls the relative picture quality among the video progran1s transmitted over a single channel as well as provides more consistent and higher picture quality than independent coding scheme that encodes each program independently.