nils-herrmann/clean_scirepeval huggingface dataset:
Effect of brightness on the quality of visual 3D perception

Over the years, a consensus has been reached that the introduction of 3D entertainment can only be a lasting success if the perceived image quality and the viewing comfort are better than those of conventional 2D television. There are different factors that affect the perceived quality of 3D content. In this paper, our objective is to obtain a good understanding of the effect that brightness has on the visual quality of 3D videos and compare it to that of the 2D. We capture outdoor and indoor scenes with different exposures and we perform subjective evaluation to investigate how brightness affects the perceived quality of the 3D experience.
A scheduling scheme for multiplexing of VBR sources in digital TV systems

Digital TV transmission systems allow a transmission channel to be shared by a number of sources. In order to improve the bandwidth utilization, variable bit rate encoding and statistical multiplexing techniques are usually used. However, the channel sharing requires a careful scheduling method for multiplexing. This is because the video and audio materials have to be presented at the receivers at specific points in time. In this paper, we present a novel scheduling scheme for statistical multiplexing of VBR sources. Our method is sensitive to the timing requirements of the sources and sends the packets as close to their transmission deadlines as possible. The advantages of our method are: (1) it decreases the broadcast deadline violation probability (or improves the bandwidth utilization), (2) it minimizes the delay and delay jitter of packets and (3) it generates a transport stream compliant with all the standard TV receivers. Simulations were conducted to compare our algorithm with the first-come-first-serve scheduling method. The results show that our algorithm significantly reduces both the percentage of dropped packets (by 35%-50%) and the average packet delay.
Determining bitrate requirement for UHD video content delivery

In this paper, our objective is to identify the best possible bitrate for transmitting Ultra High Definition (UHD) content at different complexity levels and frame rates. We compressed several UHD videos at different bitrate levels and evaluated their quality through subjective tests. Results revealed that when the original videos are not available, naïve viewers cannot distinguish the difference in quality for bitrates above 5.6 megabits per second (Mbps).
Efficient DVB-MHP to Blu-Ray System Information Transcoding

Blu-ray is a new-generation DVD format. Compared to the traditional DVD technology, Blu-ray offers advanced interactive features, high definition video quality and storage capacity that is more than 5 times that of DVD. DVB-MHP, on the other hand, is the latest Digital Video Broadcasting standard which supports a Multimedia Home Platform, specifically designed for offering advanced interactive TV services. Although both systems support Java-based interactivity, there are several differences between the two to make them incompatible. Our ultimate goal is to ensure compatibility between the two interactive services, enabling the video and interactive contents transmitted by the DVB-MHP system to be played in real time on the Blu-ray platform. One of the main challenges in realizing this compatibility is the conversion of DVB-MHP metadata, which are System Information transmitted in MPEG-2 Transport Stream packets, to the format supported by the Blu-ray standard. This study analyzed the differences between the two standards in terms of the System Information and proposed methods that ensure the desired compatibility. An optimized method for generating Program Association, Program Map and Selection Information contents for the Blu-ray system using DVB-MHP information at the elementary stream and transport stream levels is presented. Our approach takes advantage of the existing correlation between the two systems, adapts the existing DVB-MHP metadata, and intelligently searches for the information needed from the DVB-MHP elementary streams to generate in real-time the Blu-ray equivalent information.
Dynamic Resource Allocation for MGS H.264/AVC Video Transmission Over Link-Adaptive Networks

In this paper, we address the problem of efficiently allocating network resources to support multiple scalable video streams over a constrained wireless channel. We present a resource allocation framework that jointly optimizes the operation of the link adaptation scheme in the physical layer (PHY), and that of a traffic control module in the network or medium access control (MAC) layer in multirate wireless networks, while satisfying bandwidth/capacity constraints. Multirate networks, such as IEEE 802.16 or IEEE 802.11, adjust the PHY coding and modulation schemes to maintain the reliability of transmission under varying channel conditions. Higher reliability is achieved at the cost of reduced PHY bit-rate which in turn necessitates a reduction in video stream bit-rates. The rate reduction for scalable video is implemented using a traffic control module. Conventional solutions operate unaware of the importance and loss tolerance of data and drop the higher layers of scalable video altogether. In this paper, we consider medium grain scalable (MGS) extension of H.264/AVC video and develop new rate and distortion models that characterize the coded bitstream. Performance evaluations show that our proposed framework results in significant gains over existing schemes in terms of average video PSNR that can reach 3 dB in some cases for different channel SNRs and different bandwidth budgets.
An efficient low random-access delay panorama-based multiview video coding scheme

We present an efficient low random delay scheme for multiview video coding (MVC). In the proposed scheme, inter-view prediction (disparity estimation), which introduces time-consuming computations and random access delay to MVC, is replaced with a residue-stream coding process. Our algorithm transforms the middle view to a panoramic view of the scene. Then the residue streams are created as the difference of the luma and chroma values of overlapping regions of each view and the panoramic view. Finally the panoramic stream and all residue streams are encoded separately (simulcast coding). The hierarchical B picture prediction structure is implemented for coding each stream. Performance evaluations show that our proposed coding method outperforms the recent multiview video coding standard by up to 2.13 dB PSNR and enhances the compression ratio by 24.6%, while reducing random-access delay by 50%.
An Encoder Complexity Reduction Scheme for Quality/Fidelity Scalable HEVC

Due to the compression performance of the latest coding standard known as high efficiency video coding (HEVC), there has been a significant interest in developing a scalable version to address industry's demand for cost effective universal access of digital media. One of the issues with the scalable extension of HEVC (known as SHVC) is its computational complexity. The focus of this study is on developing complexity reduction schemes for SHVC encoder with quality/fidelity scalability. In this paper, we propose a complexity reduction scheme for quality scalable extension of HEVC with two enhancement layers. The proposed scheme potentially can make coding/transmission of several different-quality versions of the same video content in one bit-stream an attractive proposition for the content delivery industry, allowing for cost effective digital media delivery to a variety of playback display devices. Performance evaluations confirm that the proposed complexity reduction scheme reduces total SHVC's encoding time by up to 51.95% while maintaining the overall quality of the coded streams.
Modeling of Loss-Distortion in Hierarchical Prediction Codecs

Existing video distortion models used for hybrid video codecs do not match the hierarchical prediction structure employed in SVC. In this paper, we derive a new video distortion model that captures the sensitivity to frame losses of a hierarchical prediction video decoder using the picture copy (PC) concealment strategy of SVC. Existing frameworks only cover non-scalable coders, and therefore, fall short of accurately modeling scalable coders due to the additional parameters that come into play. Performance evaluations show that our model closely approximates the loss-distortion of hierarchical coders for video sequences with different levels of motion, with exceptional performance in sequences with homogeneous levels of motion
Low redundancy layered multiple description scalable coding using the subband extension of H.264/AVC

The task of broadcasting video in wireless environments requires high coding efficiency in addition to reliable error resilience techniques. Existing solutions are set to tackle either coding efficiency and bandwidth utilization on the one hand, or error resilience and recovery from packet delay or loss on the other. We propose a novel combined approach to deal with the problem of video broadcast over wireless networks by offering a layered multiple description scalable coding (LMDSC) technique using the subband extension of H.264. This approach combines the high coding efficiency and layered structure of the subband extension of H.264/AVC along with the highly error resilient performance of multiple description coding (MDC) while virtually eliminating all redundancy between the transmitted video streams. Performance evaluations show that when faced with the same amount of packet loss, our approach achieves significant improvement in PSNR over existing methods.
An access control video watermarking method that is robust to geometric distortions

A new video watermarking algorithm for access control is introduced. This method is content- dependent and uses the dual tree complex wavelet transform (DT CWT) to create a watermark that is robust to geometric distortions and lossy compression. The watermark is a random array of 1's and -1's. A one-level DT CWT is applied to this watermark and the coefficients of this transformation are embedded into selected frequency components of the video sequence. The robustness of this method is tested against a joint attack, which involves rotation, scaling, cropping and H.264 video compression.
Analysis of the Impact of Demosaicking on JPEG Image Compression

Most consumer digital cameras capture colour data using a single light sensor with a colour filter array (CFA). This results in a mosaic image where each pixel location contains either a red, green or blue sample, and the two missing colours must be interpolated from the surrounding samples in a process called demosaicking. After demosaicking the image is typically compressed with lossy methods. In this paper we examine the impact demosaicking has on subsequent JPEG compression of still images. Simulations indicate the demosaicking method chosen affects the amount of error introduced in the compression stage and that the amount of compression applied affects the benefit from using more advanced demosaicking methods.
An Efficient Re-quantization Error Compensation for MPEG2 to H.264 Transcoding

During transcoding, the coefficients have to pass through another quantization step. This introduces re-quantization errors to the coefficients. H.264 integer transform and quantization features are different from those of MPEG2 and other standards. Based on these features, in MPEG2 to H.264 transcoding, an efficient algorithm that measures the re-quantization error is proposed. Then this measured error is used to compensate for the quality loss in transcoding. The experimental results from four typical video test sequences show that the proposed compensation procedure improves the PSNR value by about 4.82 dB. The error calculation and compensation could be carried in the transform domain resulting in significant computational saving
Bit-rate estimation for bit-rate reduction H.264/AVC video transcoding in wireless networks

Multimedia applications such as video streaming and mobile TV are emerging as the most promising applications over wireless networks. The increased coding efficiency and network friendly architecture of the latest video coding standard H.264/AVC has facilitated the delivery of coded video content to wireless users. However, wireless networks allow lower transmission bit-rates than wired networks while the display resolution of mobile devices is generally smaller than that of standard definition (SD) TV. This calls for fast bit-rate reduction techniques through video transcoding that can deliver the best video quality to the mobile receiver while adhering to the bit-rate constraints of the wireless network. In this paper, we present a bit-rate estimation model that speeds up the transcoding process by predicting the transcoded video bit-rate for different spatial resolution reduction ratios and quantization steps. We demonstrate that, on average, our proposed model can accurately estimate the bit-rate of the transcoded video to within 5% of the actual bit-rate of the transcoded video.
Correcting unsynchronized zoom in 3D video

When capturing 3D video with a stereoscopic camera setup, it is important for the cameras to be precisely aligned and synchronized. This is particularly difficult in transitions such as zooming where the camera parameters must be changed in unison, or else the perceived 3D effect will be degraded. In this paper we study the problem of unsynchronized zooming in 3D video. First, we present a subjective study that shows that the perceived quality of stereo video is greatly reduced if the two views are zoomed by different amounts. Next, we present a method for correcting zoom mismatch by applying cropping and scaling to ones of the views. Our method involves finding matching points between the left and right views, and performing least-squares regressions to estimate the amount of scaling and cropping required to make the views consistent. Experiments were performed on videos with digitally introduced zoom mismatch and videos with optical unsynchronized zoom. In both cases the results show that our method is highly accurate and produces videos without size differences or vertical parallax between the two views.
Fair scheduling for real-time multimedia support in IEEE 802.16 wireless access networks

Successful deployment of Broadband Wireless Access Networks such as WiMAX (IEEE 802.16) will be contingent on provisions for supporting multimedia traffic. In this paper, we review the quality of service features of access networks such as the 802.16 standard, and identify algorithms and schemes that are needed for supporting multimedia traffic in such networks. The 802.16 standard only specifies the features that should be implemented and leaves the design of a quality of service solution to developers. This includes the design of a mandatory scheduling framework. We present a comprehensive multimedia support framework based on the standard features. The framework specifies the architectures for the base station and the subscriber station, and contributes a number of algorithms for different service provisioning objectives. We use the concept of virtual packets to provide fair packet based centralized scheduling of uplink and downlink packets. The presented solution also provides algorithms for temporal and throughput fair scheduling in multirate physical layer of the 802.16 networks. An important part of the presented design is a multi-class fair scheduling scheme which is proposed for providing better delay performance for real time applications, while maintaining slightly longer term fairness.
Improving depth map compression using a 3-phase depth map correction approach

Autosteroscopic multiview displays are the future of 3D technology. At the same time, this technology requires transmission of multiple video streams and depth maps, increasing the necessity for efficient compression. In this work, we address the challenging issue of 3D and multiview compression by introducing a method that corrects depth maps to achieve high quality synthesized views while significantly reducing the required bitrate. Our proposed method uses a three-phase depth map correction, including eliminating anomalies, segmentation, depth value correction, and finally inter-frame and intra-frame filtering. Subjective performance evaluations show that our method yields high quality synthesized views while significantly reduces the required bandwidth for the corrected depth maps (up to 48%).
Adaptive compression coding

A compression technique which preserves edges in compressed pictures is developed. The proposed compression algorithm adapts itself to the local nature of the image. Smooth regions are represented by their averages and edges are preserved using quad trees. Textured regions are encoded using BTC (block truncation coding) and a modification of BTC using look-up tables. A threshold using a range which is the difference between the maximum and the minimum grey levels in a 4*4 pixel quadrant is used. At the recommended value of the threshold (equal to 18), the quality of the compressed texture regions is very high, the same as that of AMBTC (absolute moment block truncation coding), but the edge preservation quality is far superior to that of AMBTC. Compression levels below 0.5-0.8 b/pixel may be achieved.
Joint media-channel aware unequal error protection for wireless scalable video streaming

In this paper, we propose a joint source-channel unequal error protection scheme for scalable video streaming over capacity constrained high speed packet access (HSPA) networks. Conventional link adaptation schemes in HSPA networks use the modulation and coding scheme (MCS) that achieves a preset channel frame error rate. Our scheme utilizes video priority information along with channel quality information to set the channel coding rate that maximizes the cumulative coding rate of channel coding and application layer unequal error protection. Performance evaluations show that that under the same constraints our scheme results in an average performance improvement of 0.5dB in video PSNR for different channel conditions and different video sequences.
A new hybrid approach for view extrapolation and hole filling

Generating high quality synthesized views is key factors in the successful adoption of multiview and stereoscopic 3D TV technology. One of the main issues regarding synthesized views is the occluded regions which appear as holes in the virtual views. Filling these holes is even more challenging when only one view is available and other views need to be generated via extrapolation. These holes must be filled with texture data that resembles the real texture that would exist in the real view. We present a new method for filling these holes, which allows for realistic texture data to be used, thus improving the perceived quality of the extrapolated view. Our subjective results show that our method outperforms the current state-of-the art synthesizing approach.
A similarity measure for analyzing human activities using human-object interaction context

Understanding the context of human-object interactions plays an important role in human activity recognition. Modeling the interaction context is a challenging problem due to the large number of possible objects in the scene and the large number of ways these objects may seem to relate to human activities taking place in the scene. In addition, providing labeling information of the object and human body parts is a very difficult and labor intense part of the training process. In this paper, we use a new class of kernels for image/video data as an extension of string kernels for 2 and 3 dimensional signals to model the human body parts and objects interaction context. In contrast to similar works, the proposed method does not require labeling of the human body parts and objects in the scene for the learning process, making it more practical when dealing with large datasets. Our experimental results show that the proposed kernel efficiently models the context of human-object interactions in image/video sequences and results in improved performance when compared to state-of-the-art methods.
Compression Efficiency of High Dynamic Range and Wide Color Gamut Pixel’s Representation

Ultra-high definition (UHD) is currently being deployed in video distribution pipelines for improved quality of experience. This new recommendation not only improves spatial and temporal resolution, but also the quality and accuracy of pixels using wide color gamut (WCG) and high dynamic range (HDR) technologies. Indeed, HDR video technology aims at conveying the full range of perceptible shadow and highlight details with enough different tonal levels to prevent loss of visual information, while WCG increases the amount of visible color that can be represented. However, these technologies require different standard digital pixel representations than the ones currently employed in high definition (HD) television. While the impact of increasing spatial and temporal resolution (i.e., increase of resolution and frame rate) on compression efficiency has already been assessed, it is not clear how new pixel representations would affect the compression performance. In this paper, we discuss the differences between HD color pixel representation and the newly standardized representations developed to meet the requirements introduced by WCG and HDR. Moreover we explain why existing HD pixel representations are sub-efficient for encoding HDR and WCG pixels. We also perform a statistical analysis of pixel distribution in real images to explain how pixel’s representation influences compression efficiency. Results show that by tailoring a pixel representation upon the range of luminance and color values accessible in content and displays, bandwidth savings can be achieved while increasing the quality of delivered content. We conclude this paper by discussing the shortcomings of the color pixel representation recommended for the UHD television standards and provide guidelines to create a more efficient one.
On-the-fly tone mapping for backward-compatible high dynamic range image/video compression

In this paper, we propose a real-time tone-mapping scheme for backward compatible high dynamic range (HDR) video compression. The appropriate choice of a tone-mapping operator (TMO) can significantly improve the HDR quality reconstructed from a low dynamic range (LDR) version. We develop a statistical model that approximates the mean square error (MSE) distortion resulting from the combined processes of tone-mapping and compression. Using this model, we formulate a numerical optimization problem to find the tone-curve that minimizes the expected MSE in the reconstructed HDR sequence. We then simplify the developed model in order to reduce the computational complexity of the optimization problem to a closed-form solution. Performance evaluations show that the proposed methods provide superior performance in terms of HDR MSE and SSIM compared to existing tone-mapping schemes. It is also shown that the LDR image quality resulting from the proposed methods matches that produced by perceptually-based TMOs.
Rate and distortion modeling of medium grain scalable video coding

Scalability in video coding is becoming the primary choice for providing quality of service (QoS) guarantees in wireless video communication. In this paper, we develop real-time rate and distortion prediction models for medium grained scalable (MGS) coded video streams. These models allow mobile video encoders to predict the packet size and corresponding distortion of a video frame using only the mean absolute difference (MAD) of the motion prediction and the quantization parameter (QP). The prediction of rate and distortion measures can be used in devices with cross layer optimization capabilities to choose the combination of base and enhancement layer packets that deliver the best picture quality given channel quality information. Performance evaluations demonstrate that our models accurately predict the size and distortion of base and enhancement layer MGS packets.