Quarter Common Intermediate Format Research Articles

On accounting for screen resolution in adaptive video streaming: QoE‐driven bandwidth sharing framework

SummaryScreen resolution along with network conditions are main objective factors impacting the user experience, in particular for video streaming applications. User terminals on their side feature more and more advanced characteristics resulting in different network requirements for good visual experience. Previous studies tried to link mean opinion score (MOS) to video bitrate for different screen types (e.g., Common Intermediate Format [CIF], Quarter Common Intermediate Format [QCIF], and High Definition [HD]). We leverage such studies and formulate a Quality of Experience (QoE)‐driven resource allocation problem to pinpoint the optimal bandwidth allocation that maximizes the QoE over all users of a network service provider located behind the same bottleneck link, while accounting for the characteristics of the screens they use for video playout. For our optimization problem, QoE functions are built using curve fitting on datasets capturing the relationship between MOS, screen characteristics, and bandwidth requirements. We propose a simple heuristic based on Lagrangian relaxation and Karush Kuhn Tucker (KKT) conditions to efficiently solve the optimization problem. Our numerical simulations show that the proposed heuristic is able to increase overall QoE up to 20% compared to an allocation with a TCP look‐alike strategy implementing max‐min fairness.

Conservative Approximation–Based Full-Search Block Matching Algorithm Architecture for QCIF Digital Video Employing Systolic Array Architecture

This paper presents a power-efficient hardware realization for a motion estimation technique that is based on the full-search block matching algorithm (FSBMA). The considered input is the quarter common intermediate format of digital video. The mean of absolute difference (MAD) is the distortion criteria employed for the block matching process. The conventional architecture considered for the hardware realization of FSBMA is that of the shift register-based 2-D systolic array. For this architecture, a conservative approximation technique is adapted to eliminate unnecessary MAD computations involved in the block matching process. Upon introducing the technique to the conventional architecture, the power and complexity of its implantation is reduced, while the accuracy of the motion vector extracted from the block matching process is preserved. The proposed architecture is verified for its functional specifications. A performance evaluation of the proposed architecture is carried out using parameters such as power, area, operating frequency, and efficiency.

Robust 2D principal component analysis: a structured sparsity regularized approach.

Principal component analysis (PCA) is widely used to extract features and reduce dimensionality in various computer vision and image/video processing tasks. Conventional approaches either lack robustness to outliers and corrupted data or are designed for one-dimensional signals. To address this problem, we propose a robust PCA model for two-dimensional images incorporating structured sparse priors, referred to as structured sparse 2D-PCA. This robust model considers the prior of structured and grouped pixel values in two dimensions. As the proposed formulation is jointly nonconvex and nonsmooth, which is difficult to tackle by joint optimization, we develop a two-stage alternating minimization approach to solve the problem. This approach iteratively learns the projection matrices by bidirectional decomposition and utilizes the proximal method to obtain the structured sparse outliers. By considering the structured sparsity prior, the proposed model becomes less sensitive to noisy data and outliers in two dimensions. Moreover, the computational cost indicates that the robust two-dimensional model is capable of processing quarter common intermediate format video in real time, as well as handling large-size images and videos, which is often intractable with other robust PCA approaches that involve image-to-vector conversion. Experimental results on robust face reconstruction, video background subtraction data set, and real-world videos show the effectiveness of the proposed model compared with conventional 2D-PCA and other robust PCA algorithms.

Rate-distortion optimised quantisation for direct current coefficients of Wyner–Ziv frame in unidirectional distributed video coding

This study presents a rate-distortion (RD) optimised quantisation algorithm for direct current (DC) coefficients of the Wyner–Ziv (WZ) frames in unidirectional distributed video coding. As the side information (SI) could be viewed as a ‘corrupted’ version of the original WZ frame, the correlation noise (WZ-SI) can be interpreted as a virtual channel with an error pattern. In this study, the distortion caused by virtual channel errors, besides quantisation errors, is analysed emphatically for unidirectional WZ video coding. In their presented quantisation algorithm, a novel RD model is developed to find out the optimal quantisation step size, in which the quantisation distortion and virtual channel error distortion together with the encoding rate are formulated using the quantisation step size without feedback channels. Then the RD optimal step size for DC coefficients can be solved through minimising the RD cost. In simulations, the comparison of RD performance between their proposed algorithm and the quantisation method used in distributed coding for video services (DISCOVER) is presented. Experimental results show that the proposed RD optimised quantisation for DC coefficients can improve the average peak signal-to-noise ratio of WZ frames by 0.4–1.2 dB for quarter common intermediate format (QCIF) sequences and 0.2–0.4 dB for common intermediate format (CIF), at the expense of increasing the encoding complexity slightly.

An MPEG-2 to H.264 Video Transcoder in the Baseline Profile

Based on our previous efforts, we introduce in this letter a high-efficient MPEG-2 to H.264 transcoder for the baseline profile in the spatial domain. Machine learning tools are used to exploit the correlation between the macroblock (MB) decision of the H.264 video format and the distribution of the motion compensated residual in MPEG-2. Moreover, a dynamic motion estimation technique is also proposed to further speed-up the decision process. Finally, we go a step further on our previous research efforts by combining the two aforementioned speed-up approaches. Our simulation results over more than 40 sequences at common intermediate format and quarter common intermediate format resolutions show that our proposal outperforms the MB mode selection of the rate-distortion optimization option of the H.264 encoder process by reducing the computational requirements by up to 90%, while maintaining the same coding efficiency. Finally, we conduct a comparative study of our approach with the most relevant fast inter-prediction methods for MPEG-2 to H.264 transcoder recently reported in the literature.

Adaptive Unicast Video Streaming With Rateless Codes and Feedback

Video streaming over the Internet and packet-based wireless networks is sensitive to packet loss, which can severely damage the quality of the received video. To protect the transmitted video data against packet loss, application-layer forward error correction (FEC) is commonly used. Typically, for a given source block, the channel code rate is fixed in advance according to an estimation of the packet loss rate. However, since network conditions are difficult to predict, determining the right amount of redundancy introduced by the channel encoder is not obvious. To address this problem, we consider a general framework where the sender applies rateless erasure coding to every source block and keeps on transmitting the encoded symbols until it receives an acknowledgment from the receiver indicating that the block was decoded successfully. Within this framework, we design transmission strategies that aim at minimizing the expected bandwidth usage while ensuring successful decoding subject to an upper bound on the packet loss rate. In real simulations over the Internet, our solution outperformed standard FEC and hybrid automatic repeat request approaches. For the quarter common intermediate format Foreman sequence compressed with the H.264 video coder, the gain in average peak signal to noise ratio over the best previous scheme exceeded 3.5 dB at 90 kb/s.

Reduced-Resolution Intra Block Coding Mode

In this letter, a new intra-block coding mode is presented to improve the coding efficiency for band-limited signals. A band-limited block is sub-sampled, and the sub-sampled signal is coded on the basis of the conventional prediction/transform coding. The rest of the samples are reconstructed by interpolation at the decoder side without any side information. Experimental results show that the proposed algorithm achieves coding gains of 2.7% for common intermediate format (CIF), 4.29% for quarter CIF, and 6.39% for 720p60 sequences against the H.264/AVC JM10.2 reference software.

A 125 $\mu{\hbox{W}}$, Fully Scalable MPEG-2 and H.264/AVC Video Decoder for Mobile Applications

A low-power dual-standard video decoder has been developed for mobile applications. It supports MPEG-2 SP@ML and H.264/AVC BL@L4 video decoding in a single chip and features a scalable architecture to reach area/power efficiency. This chip integrates diverse algorithms of MPEG-2 and H.264/AVC to reduce silicon area. Three low-power techniques are proposed. First, a domain-pipelined scalability (DPS) technique is used to optimize the pipelined structure according to the number of processing cycles. Second, bandwidth scalability is implemented via a line-pixel-lookahead (LPL) scheme to improve the external bandwidth and reduce the internal memory size, leading to 51% of memory power reduction compared to a conventional design. Third, low-power motion compensation and deblocking filter are designed to reduce the operating frequency without degrading system performance. A test chip is fabricated in a 0.18mum one-poly six-metal CMOS technology with an area of 15.21 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . For mobile applications, H.264/AVC and MPEG-2 video decoding of quarter-common intermediate format (QCIF) sequences at 15 frames per second are achieved at 1.15 MHz clock frequency with power dissipation of 125 muW and 108 muW, respectively, at 1V supply voltage

An assessment of the video image quality required in a remote vision guidance system for visually impaired pedestrians

A study was carried out to determine the most acceptable quality of video images for use in remote guidance of visually impaired pedestrians. A video image clip of 20 s duration was captured using a digital camera, while walking a sample route. The video image clip was encoded at bit rates of 30 and 48 kbit/s, and frame rates of 10, 7.5, 5 and 2.7 fps. Two standard resolutions were used: Quarter Common Intermediate Format (QCIF) (176 x 144 pixels) and Common Intermediate Format (CIF) (352 x 288 pixels). Twelve participants gave their judgment on the picture update rate (smoothness of movement), the bit rate and the static resolution. The mean scores for total quality (five-point scale) ranged from 3.3 to 4.8, but there was no significant difference between them. The mean scores for smoothness (five-point scale) ranged from 3.0 to 4.7, but there was no significant difference between them. The mean score for the resolution of the QCIF video clips was 2.9 (SD = 0.9) and for the CIF recordings were 4.1 (SD = 0.7), but there was no significant difference between them. The majority of the participants were most comfortable with video which was transmitted at 48 kbit/s and 7.5 fps. Therefore, this quality can be considered satisfactory for remote guidance.

Customizing Multiprocessor Implementation of an Automated Video Surveillance System

This paper reports on the development of an automated embedded video surveillance system using two customized embedded RISC processors. The application is partitioned into object tracking and video stream encoding subsystems. The real-time object tracker is able to detect and track moving objects by video images of scenes taken by stationary cameras. It is based on the block-matching algorithm. The video stream encoding involves the optimization of an international telecommunications union (ITU)-T H.263 baseline video encoder for quarter common intermediate format (QCIF) and common intermediate format (CIF) resolution images. The two subsystems running on two processor cores were integrated and a simple protocol was added to realize the automated video surveillance system. The experimental results show that the system is capable of detecting, tracking, and encoding QCIF and CIF resolution images with object movements in them in real-time. With low cycle-count, low-transistor count, and low-power consumption requirements, the system is ideal for deployment in remote locations.

Fast search algorithms for video coding using orthogonal logarithmic search algorithm

The paper presents a novel fast search algorithm for block base motion compensation called the orthogonal logarithmic search. The performance of the algorithm is evaluated by using standard 176 x144 pixels quarter common intermediate format (QCIF) benchmark video sequences and the results are compared to the traditional well-known full search algorithm and the sub-optimal three step search which is used in international video coding standards such as ISO MPEG-1/2 and ITU-T H.263. The important metrics of time and peak signal to noise ratio are used to evaluate the novel algorithm. The results show that the strength of the algorithm lies in its speed of operation as it is much faster than both the full search algorithm and the three step search. It has speed advantages of almost 87% and over 23% over the full search and three step search algorithms respectively. Furthermore, the accuracy of the prediction of orthogonal logarithmic search algorithm is comparable to that of the three step search.

Algorithm and VLSI architecture for high performance adaptive video scaling

We propose an efficient high-performance scaling algorithm based on the oriented polynomial image model. We develop a simple classification scheme that classifies the region around a pixel as an oriented or nonoriented block. Based on this classification, a nonlinear oriented interpolation is performed to obtain high quality video scaling. In addition, we also propose a generalization that can perform scaling for arbitrary scaling factors. Based on this algorithm, we develop an efficient architecture for image scaling. Specifically, we consider an architecture for scaling a Quarter Common Intermediate Format (QCIF) image to 4CIF format. We show the feasibility of the architecture by describing the various computation units in a hardware description language (Verilog) and synthesizing the design into a netlist of gates. The synthesis results show that an application specific integrated circuit (ASIC) design which meets the throughput requirements can be built with a reasonable silicon area.

High efficiency and low power consumption in active matrix organic light emitting diodes

Abstract Phosphorescent full color 2.2 inch quarter common intermediate format (QCIF) active matrix organic light emitting diodes (AMOLED) have been developed for mobile phone application. Red and green phosphorescent emitters have been adopted as light emitting components and the efficiency of the AMOLED as measured was enhanced up to 10.9 cd/A at a white brightness of 100 cd/m2. The power consumption of the AMOLED was reduced below 200 mW due to high efficiency and low driving voltage.

CIF-to-QCIF video bitstream down-conversion in the DCT domain

Many advanced video applications require converting a compressed video bitstream from the Common Intermediate Format (CIF) to the Quarter Common Intermediate Format (QCIF). This task could be performed in the pixel domain or in the discrete cosine transform (DCT) domain. In this paper, we propose a DCT-domain approach, which requires lower complexity than that in the pixel domain. We also propose a scheme for selecting a coding mode and a motion vector for a macroblock (MB) in a QCIF video sequence from those of the corresponding CIF video without motion estimation (ME), which is computationally very expensive. Simulation results show that our DCT-domain approach reduces computational complexity by about 40% compared to the pixel-domain approach while providing comparable picture quality with about 0.4 dB degradation.

37.3: High Performance 2.2″ QCIF Full Color AMOLED Display based on Electrophosphorescence

AbstractFull color 2.2‐inch Quarter Common Intermediate Format (QCIF) organic EL displays were developed using phosphorescent materials and low temperature poly‐Si (LTPS) technology. These displays exhibited a world record efficiency of 11cd/A at an optimized white CIE coordinate of (0.31, 0.32) with an OLED operating voltage of 6V. The current pixel structure for the 2.2‐inch display allows about 32% aperture ratios and a white peak luminance of over 300cd/m2.

Burst-by-burst adaptive joint detection CDMA/H.263 based video telephony

Since wireless channels exhibit dramatic near-instantaneous channel-quality fluctuations, it is unrealistic to expect that a transceiver relying on time-invariant modulation and coding modes is capable of delivering as good a performance as a near-instantaneously adaptive arrangement. Hence, a near-instantaneously adaptive joint-detection code division multiple access (CDMA)-based video transceiver is proposed for wireless video telephony. Specifically, the transceiver is capable of reconfiguring itself in 1, 2 and 4 bits/symbol direct-sequence CDMA modes and delivers an unimpaired video quality associated with a peak signal-to-noise ratio (PSNR) of 34-41 dB for channel SNRs in excess of about 5 dB over the COST207 bad urban channel model at video rates between 5-26.9 kbits/s using 176/spl times/144 pixel quarter common intermediate format (QCIF) and 128/spl times/96 pixel sub-QCIF (SQCIF) video formats.

Multipriority video transmission for third-generation wireless communication systems

This paper presents a robust dual-priority video partitioning method suitable for twin-class unequal protected video transmission over wireless channels. The partitioning is based on a separation of the variable-length (VL) coded discrete cosine transform (DCT) coefficients within each block. The scheme is suitable for constant bit-rate transmission (CBR), where the fraction of bits assigned to each of the two partitions can be adjusted according to the requirements of the unequal error-protection scheme employed. The distribution of the VL-coded (VLC) information between the two partitions is performed adaptively. Subsequently, the partitioning method was applied to the ITU-T H.263 coding standard. It was shown that, for the input video with quarter common intermediate format (QCIF) spatial resolution (or less), the partitioning overhead can be embedded in the B-bit code word representing the group number (GN), thus avoiding transmission of additional bits. As a transport vehicle, we have considered one of the leading third generation cellular radio standards known as wide-band code division multiple access (W-CDMA). A dual-priority transmission system is then invoked on the W-CDMA system where the video data, after being broken into two streams, are unequally protected. We use a very simple error-correction coding scheme for illustration and then propose more sophisticated forms of unequal protection of the digitized video signals. We show that this strategy results in a significantly higher quality of the reconstructed video data when they are transmitted over time-varying multipath fading channels.

Multi-frame packet reservation multiple access using oscillation-scaled histogram-based Markov modelling of video codecs

Abstract A model is proposed for replacing the video codec in networking studies, which is tested for sources with a mean bit-rate in the range of 10 Kb/s to 10 Mb/s. The standard frame sizes investigated are the International Telecommunications Union’s (ITU) 352×288-pixel Common Intermediate Format (CIF), 176×144-pixel Quarter CIF (QCIF), 704×576-pixel 4CIF and 128×96-pixel Sub-QCIF (SQCIF). The proposed 20-state ‘oscillation-scaled’ Markov model was found to represent the relevant video codec characteristics adequately. The performance of this model is then tested in the context of a novel Multi-frame Packet Reservation Multiple Access or MF-PRM A scheme, which is shown in Fig. 17 to outperform conventional PRMA in terms of both its delay and packet dropping performance, reaching throughput values as high as 79%.

Edge-based motion estimation and region-based contour tracing for very low bit rate video coding

A new algorithm for image sequence coding with a very low bit rate and high picture quality is proposed. The proposed cod- ing system is composed of interframe and intraframe coding. In the interframe coding, an edge-based motion estimation algorithm is used to find the motion vector of a moving block instead of using the conventional block-matching algorithm. The edge-based method re- duces the entropy of the estimated motion vectors within a frame. Since the motion vectors are usually encoded by entropy coding, bit rate is also reduced. In the intraframe coding, a region-based algo- rithm is used to trace the contour of an object and estimate its pa- rameters from a predetermined database of various geometric shapes. It can reduce the blocking effect. By testing several image sequences such as ''Miss America'' and ''Claire'' with 10 frames/s in quarter common intermediate format (QCIF) the proposed coding system has about 1 to 2 dBs higher peak SNRs than the H.263 system. © 1998 SPIE and IS&T. (S1017-9909(98)01401-9)

A 60-mW MPEG4 video codec using clustered voltage scaling with variable supply-voltage scheme

A 60-mW MPEG4 video codec has been developed for mobile multimedia applications. This codec supports both the H.263 ITU-T recommendation and the simple profile of MPEG4 committee draft version 1 released in November 1997. It is composed of a 16-bit reduced instruction set computer processor and several dedicated hardware engines so as to satisfy both power efficiency and programmability. It performs 10 frames/s of encoding and decoding with quarter-common intermediate format at 30 MHz. Several innovative low-power techniques were employed in both architectural and circuit levels, and the final power dissipation is 60 mW at 30 MHz, which is only 30% of the power dissipation for a conventional CMOS design. The chip was fabricated in a 0.3-/spl mu/m CMOS with double-well and triple-metal technology. It contains 3 million transistors, including a 52-kB on-chip SRAM. Internal supply voltages of 2.5 and 1.75 V are generated by on-chip dc-dc converters from 3.3-V external supply voltage.