Analog Video Transmission Research Articles

JSCC-Cast: A Joint Source Channel Coding Video Encoding and Transmission System with Limited Digital Metadata.

This work considers the design and practical implementation of JSCC-Cast, a comprehensive analog video encoding and transmission system requiring a reduced amount of digital metadata. Suitable applications for JSCC-Cast are multicast transmissions over time-varying channels and Internet of Things wireless connectivity of end devices having severe constraints on their computational capabilities. The proposed system exhibits a similar image quality compared to existing analog and hybrid encoding alternatives such as Softcast. Its design is based on the use of linear transforms that exploit the spatial and temporal redundancy and the analog encoding of the transformed coefficients with different protection levels depending on their relevance. JSCC-Cast is compared to Softcast, which is considered the benchmark for analog and hybrid video coding, and with an all-digital H.265-based encoder. The results show that, depending on the scenario and considering image quality metrics such as the structural similarity index measure, the peak signal-to-noise ratio, and the perceived quality of the video, JSCC-Cast exhibits a performance close to that of Softcast but with less metadata and not requiring a feedback channel in order to track channel variations. Moreover, in some circumstances, the JSCC-Cast obtains a perceived quality for the frames comparable to those displayed by the digital one.

Human-Perception-Oriented Pseudo Analog Video Transmissions With Deep Learning

Recently, pseudo analog transmission has gained increasing attentions due to its ability to alleviate the cliff effect in video multicast scenarios. The existing pseudo analog systems are sorely optimized under the minimum mean squared error criterion without taking the perceptual video quality into consideration. In this paper, we propose a human-perception-based pseudo analog video transmission system named ROIC-Cast, which aims to intelligently enhance the transmission quality of the region-of-interest (ROI) parts. Firstly, the classic deep learning based saliency detection algorithm is adopted to decompose the continuous video sequences into ROI and non-ROI blocks. Secondly, an effective compression method is used to reduce the data amount of side information generated by the ROI extraction module. Then, the power allocation scheme is formulated as a convex problem, and the optimal transmission power for both ROI and non-ROI blocks is derived in a closed form. Finally, the simulations are conducted to validate the proposed system by comparing with a few of existing systems, e.g., KMV-Cast, SoftCast, and DAC-RAN. The proposed ROIC-Cast can achieve over 4.1dB peak signal- to-noise ratio gains of ROI compared with other systems, given the channel signal-to-noise ratio as -5dB, 0dB, 5dB, and 10dB, respectively. This significant performance improvement is due to the automatic ROI extraction, high-efficiency data compression as well as adaptive power allocation.

HDA Video Transmission Scheme for DASH

In recent years, with the development of Internet communication technology, more and more people tend to get information through the network. And people prefer multimedia video streaming services. Traditional streaming media technology cannot meet people's needs because of its limitations. Recently, HTTP-based Dynamic Adaptive Streaming Over HTTP (DASH) has emerged as a new approach. In this paper, we consider two hybrid digital and analog video transmission schemes for DASH and propose three methods of enhancing the video quality of experience (QoE) of DASH users. First of all, considering the importance of data to video quality, we propose an energy-aware recombination method of reorganizing and packaging data and define the priority of the generated DASH layer in transmission. Second, we design an adaptive bitrate allocation algorithm to improve bandwidth utilization and video quality. Finally, we propose a retransmission mechanism to address the situation in which the digital stream at the receiving end cannot be decoded due to channel distance errors. Experiments show that our two schemes are superior to traditional DASH schemes.

Distortion Estimation-Based Adaptive Power Allocation for Hybrid Digital–Analog Video Transmission

Hybrid digital–analog (HDA) video transmission schemes have shown advantages in avoiding the cliff effect . However, most current HDA schemes assume perfect transmission of the digital signal, which is hardly the case in practice. In this paper, we propose an adaptive recursive distortion estimate for the HDA system (ARDE-HDA), which recursively estimates the decoder-side distortion from the encoder and adaptively allocates the transmission power between the digital and analog signals in HDA. First, we derive the closed-form expression of a recursive distortion estimation (RDE) method, which does not require the digital part of the HDA output to be decoded perfectly, and both transmission error and superposition process of digital and analog parts are taken into consideration. Then, based on the deduced RDE model, an adaptive power allocation is proposed for the digital and analog parts to minimize the decoder-side distortion. Finally, simulation results are presented, which show the accuracy of the proposed RDE model and the ARDE-HDA method. Our method can achieve an average of 4.10 dB gain over existing HDA methods and 15.14-dB gain over the Softcast method in terms of the peak signal-to-noise ratio.

High-Quality Soft Video Delivery With GMRF-Based Overhead Reduction

Soft video delivery, i.e., analog video transmission, has been proposed to provide high video quality in unstable wireless channels. However, existing analog schemes need to transmit a significant amount of metadata to a receiver for power allocation and decoding operations causing large overhead and quality degradation due to rate and power losses. To reduce the overhead while keeping the video quality high, we propose a new analog transmission scheme. Our scheme exploits a Gaussian Markov random field for modeling video sequences to significantly reduce the required amount of metadata, which are obtained by fitting into the Lorentzian function. Our scheme achieves not only reduced overhead but also improved video quality, by using the fitting function and parameters for metadata. Evaluations using several test video sequences demonstrate that the proposed scheme reduces overhead by 99.7% with 1.2-dB improvement of video quality (in terms of peak signal-to-noise ratio) compared to the existing analog video transmission scheme. We also investigate the impact of bandwidth limitation, showing a significant gain up to 2.7 dB for narrow-band systems.

An Optimal Resource Allocation for Superposition Coding-Based Hybrid Digital–Analog System

Hybrid digital–analog (HDA) video transmission is a new cross-layer design, which can be widely used in Internet of Things. The key problem of HDA video transmission is to find the optimal resource allocation between the digital and analog part. This paper presents a new general resource allocation algorithm for superposition coding-based HDA system. On one hand, in order to achieve successful decoding in digital part, the bitrate is controlled by the quantization parameter (QP), and the channel coding rate and modulation order are determined by the signal to interference noise power ratio, in which analog part is considered as the interference. On the other hand, the overall video quality is directly determined by the mean square error of analog part, which depends jointly on the data variance of the analog part, the power allocated to the analog part and the channel noise power. We propose a prediction model to describe how the data variance of the analog part changes with the QP in the digital part. Based on the proposed model, the power allocation of two parts can be quantitatively connected to form an optimization problem. We prove the convexity of the resource allocation problem and the gradient descent method is utilized in system implementation. With extensive simulations, the proposed algorithm is validated, achieving 1.4–5.3 dB gain over the conventional digital system, and 6.2–7.4 dB gain over pseudo-analog system in peak signal-to-noise ratio.

Adaptive Hybrid Digital–Analog Video Transmission in Wireless Fading Channel

We propose an adaptive hybrid digital–analog video transmission (A-HDAVT) scheme for robust video streaming in mobile networks with realistic fading channels. This scheme is fundamentally different from recent research in hybrid digital–analog video transmission in which wireless channels are unrealistically assumed to be Gaussian. For fading channels, it is critical to take full advantage of diversity in both video contents and multiuser channels. Like all hybrid approaches, A-HDAVT is designed to exploit the benefits from both digital and analog systems. To achieve this goal, each group of pictures is first transformed into one low-pass frame and several high-pass frames with motion-compensated temporal filtering. The critical low-pass frame is reliably transmitted as base layer in a digital mode, while high-pass frames are transmitted as enhancement layers in an analog mode to achieve desired graceful degradation performance. In analog transmission, we introduce a channel prediction-based adaptive power-distortion optimization (P-APDO) scheme to combat channel fading in mobile networks. The basic idea behind P-APDO is to perform power allocation based on the video content as well as the predicted channel status. Furthermore, we also investigate the multiuser scenarios in which the content diversity and channel diversity among users are appropriately exploited. Extensive simulations have been carried out to evaluate the performance of A-HDAVT under various degrees of channel fading. The results show that A-HDAVT achieves significant performance gains over competing schemes Robust Uncoded Video Transmission, Parcast, and Softcast in both single-user and multiuser scenarios.

Hybrid AM-VSB/256-QAM/internet transport systems in the campus

We propose and demonstrate simultaneous transport of 1556 nm downstream CATV analog video, 256-quadrature amplitude modulation (QAM) digital TV and Internet access signals, as well as 1310 nm upstream Internet access signals over the existing multimode fiber (MMF) in the campus. This technique makes possible analog and digital video transmission, gigabit Ethernet as well as Internet access to the classrooms through the existing MMF. Our proposed system has the distinctive advantages of simplicity and lower cost, and is thus eminently suitable for fiber to the classrooms application.

A hybrid DWDM system for CATV and 256‐QAM transport in the campus

AbstractIn this paper, we propose and demonstrate a 4‐wavelength hybrid dense‐wavelength‐division‐multiplexing (DWDM) system for CATV and 256‐QAM transport over a 4‐km multimode fiber (MMF) in the campus. Good performances of carrier‐to‐noise ratio (CNR), composite second order (CSO) and composite triple beat (CTB) were obtained for CATV video signals; and low bit error rate (BER) had been achieved for 256‐QAM digital passband signals over a 4‐km MMF transport. This technique makes possible analog video transmission and gigabit Ethernet to the classrooms through the existed MMF in the campus. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 000–000, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10533

Digital Video and Audio Transmission Alternatives

As television plants convert to serial digital video and digital audio, it becomes apparent that the analog and digital transmission requirements are vastly different. In analog video transmission, it is common to use custom equalizers for long cable lengths, where in digital video transmission, automatic equalization is provided for up to 300 m (1000 ft) of coaxial cable. Where longer transmission paths are required, fiber-optic links offer a better solution. Single-mode fiber-optic transmitters and receivers for serial digital video meeting the proposed SMPTE standards for a serial digital fiber transmission system for ANSI/SMPTE 259M signals' and coaxial cable distribution for AES/EBU digital audio 2 offer several advantages that are described in this paper.

Three-dimensional imaging for video telephony

The Advanced Media Unit at BT has been investigating the possibility of producing 3D video telephones. These would have to be usable with no disadvantages when compared with conventional 2D video telephones. This precludes the use of glasses-based systems. We have selected an autostereoscopic system based around a lenticular sheet as the most appropriate for our requirements. Ray-tracing models of lenticular sheet systems have been used to evaluate alternative sheet designs. Some of these alternative designs were intended to alleviate the limitations of current LCD technology. Attention was also paid to the recording aspect of 3D images. A model of the system was developed and used to calculate suitable camera positions for comfortable 3D images. Record and display components were built following the designs calculated previously. These were then used in a 3D video telephone system. Initial tests simply used analogue video transmission between the two ends, but later tests were run over the ISDN (Integrated Services Digital Network) using separate channels for left- and right-eye images. The paper will discuss this work in detail and describe the results of the experiments. Plans for further work will also be discussed.

1480-nm pumped erbium-doped fiber amplifiers with optimized noise performance for AM-VSB distribution systems

Within analog video transmission systems, optical amplifiers have to display simultaneously good noise and output power performance because of the very stringent carrier-to-noise ratio requirements imposed by the AM-VSB modulation format. We show, theoretically and experimentally, that properly designed forward 1480-nm pumped erbium-doped fiber amplifiers can deliver +16 dBm saturated output power with noise parameter (n/sub sp//C/sub x/) as low as 3.5dB. These amplifiers do not exhibit significant degradation of their noise performance when the input powers are as large as +3 dBm. These characteristics make 1480-nm pumped amplifiers suitable for AM-VSB transmission systems. >

Multilevel signaling and pulse shaping for spectrum efficiency in subcarrier multiplexing transmission

Subcarrier multiplexing (SCM) transmission has been widely used for analog video transmission in CATV systems. As digital video technology rapidly advances, there is a strong need to transmit digital video over the same SCM system. Since digital video such as HDTV requires a much larger bandwidth, multilevel signaling becomes an important approach. As the number of levels increases, however, the noise margin decreases and the system is more subject to adjacent channel interference (ACI). In this paper, we analyze the spectrum efficiency and power penalty of multilevel SCM transmission. We found that using pulse shaping can make multilevel signaling attractive. Depending on the ACI that can be tolerated, results show that multilevel amplitude-shift keying (ASK) of 5-7 b/symbol can give the optimum spectrum efficiency using the raised-cosine pulse. The price paid is a slight power penalty of 0.4 dB to reduce intersymbol interference (ISI) to zero. >

A new compound modulation technique for multichannel analog video transmission on fiber

An analog transmission technique for multichannel TV transmission on fiber using frequency-modulated/time-division multiplexing (FM/TDM) is described and compared with present digital and analog systems. Analysis and simulations indicate that the proposed system has a very low sensitivity to nonlinearities, similar to digital systems, and much better than current frequency-modulated/frequency-division multiplexed (FM/FDM) systems. This permits the use of higher optical modulation depth (as high as digital systems), which results in achieving high signal-to-noise ratio, large power budget, and/or the use of lower cost optical components. Furthermore, a better spectrum efficiency is possible.

Distortion due to gain tilt of erbium-doped fiber amplifiers

It was found experimentally and theoretically that the second-order intermodulation product, namely composite second-order (CSO) distortion, is caused by coupling of the gain tilt of an erbium-doped fiber amplifier (EDFA) with laser chirp. When the signal light is not at the gain peak of the EDFA, gain tilt exists and EDFA cannot be used in an AM-FDM optical analog video transmission system because of CSO degradation. To counteract the gain tilt induced CSO, the authors demonstrated that codoping Al and setting the laser oscillation wavelength at the gain peak are useful. Er-Al-codoped fiber amplifiers have better linearity than Er-doped fiber amplifiers because the gain tilt of the former is smaller. >

Optical Fiber: The 1990s Adaptive Television Transmission Medium

Within the “television industry,” a constantly increasing array of studio interface and recording standards for analog component, digital component and digital composite video signal waveforms now exists, supplementing the 1953 FCC-approved NTSC analog composite broadcasting standard. SMPTE 240-M is a studio interface standard for HDTV production and post-production. The “computer industry” is spawning its own array of standards for high resolution image generation. — There is an expanding demand for a terrestrial infrastructure of local and long haul fiber circuits to transmit these signals between and among a variety of unrelated business enterprise facilities. This demand in total comes from broadcasting and cable, plus business, financial, education, health care and government enterprises involved in distance learning, videoconferencing, advanced television (ATV, which includes HDTV) programming and new image transmission services. — However, the “telephone industry's” fiber infrastructure currently operates on its own hierarchy of digital standards for voice and data signal transmission. Terrestrial circuits for analog video transmission are scarce and costly. The demand for these urgently needed fiber transmission media will not become real, therefore, until the standards setters of the television and telephone industries begin to counsel together.

Time-Multiplexed Analog Transmission of Three Broadcast-Quality Television Channels Through One Satellite Transponder

This paper describes a TV signal compression scheme which may become a common practice for analog video transmission and broadcast via satellite by the year 2000. The technique uses twodimensional interfield processing to reduce the video bandwidth with minimum degradation in subjective quality, and time multiplexed with analog multiplexing technique for transmission in component format. Computer simulations of the processing technique on the test slides, and analysis of subjective quality and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S/N</tex> expected over a typical satellite link, are reported. A proof-of-concept prototype being developed at COMSAT Laboratories is also outlined.

Analogue video transmission over cabled monomode fibre using optical frequency modulation with heterodyne detection

The design and receiver sensitivity of a heterodyne detection system using analogue optical frequency modulation is examined for the transmission of a single baseband colour video signal. After transmission over 30 km of cabled monomode fibre, receiver sensitivity was measured to be −70.3 dBm for a 53 dB unified weighted video SNR.

Simple model to calculate repeater spacings on analogue optical fibre video transmission routes

Analogue video transmission over a tandem connection of optical fibre systems is examined. A simple mathematical model is presented which relates section length and fibre attenuation to route length and video SNR at the final receiver. The model takes account of any analogue modulation format and applies to direct and coherent detection.

LED linearisation for video bandwidth transmission employing a monolithically integrated PIN-PD

Nonlinear distortion and frequency response for light-emitting diodes in analogue video transmission are greatly improved by using a wideband optoelectronic feedback loop employing monolithically integrated PIN photodiodes. Large monitoring efficiency of more than 2% makes it easy to realise this wideband and high-gain feedback loop.