May2012 www.tvbeurope.com


TVBEurope 15


News & Analysis Guest Opinion


SDI:


NOW MORE than ever, with the widespread use of HD and 3G technologies along with SD, broadcasters and A/V professionals are being increasingly challenged by SDI signal management issues. SDI signals come in various forms, such as 3G, Dual Link, HD and SD, adding to the complexity of facilities and equipment. Common questions arise when


working with this technology, such as how to monitor professional grade SDI signals affordably and how to extend and duplicate these signals. Some might want to switch between two independent signals, or combine them into a single cable for efficient transport. Cinematographers dealing with 3D filmmaking, stereographers, also have some important questions regarding their monitoring and processing workflows. This raises the question ‘how far can this SDI technology go?’ The challenge of monitoring SDI signals is one of the most commonly found within the industry. Many professionals are trying to find inexpensive ways to


How far can we push it?


Charles P Amyot, Matrox Video product manager, discusses the challenge of monitoring SDI signals


monitor professional SDI signals. A solution is to convert the SDI video feed into an affordable format, such as HDMI. This process requires


extracting the image from the serial data stream of the SDI signal and transferring it to an HDMI encoder chip. The signal can then be sent to consumer grade HDMI displays. Proper calibration of the HDMI monitor is essential to precisely replicate the SDI colours. Distribution is also a


widespread challenge for SDI users, mostly in large venues where the signal needs to cover long distances. This distribution cannot be achieved with the help of a simple mechanical splitter, since this would cause significant signal degradation, while increasing return loss and jitter. For proper distribution, a repeater needs to be used, which includes an equaliser. The equaliser will ensure the reception of a proper signal by the repeater, which extends the signal. Professionals also wish to


switch between distinct video feeds. Some equipment will perform the operation anywhere


within the video frame, which will most certainly cause a glitch in the video stream. This glitch can also affect downstream devices that are being used to process or record the signal. These devices might start


dropping frames, or even fail altogether. Glitch-free switching can be achieved by following the SMPTE RP-168 specification, which states that switching should only occur on the switching line. Both video streams need to be synchronised to align both switching lines. This technique lets a device act as a true broadcast switcher, providing clean, glitch-free switching. In the case of a loss of signal, switching can also occur automatically. In this case, a device needs to detect a loss of signal via the previously mentioned equaliser, then automatically switch to the second input if the first one is lost or becomes invalid. To reduce by half the amount


of wiring needed to distribute HD-SDI signals, multiplexing can be used. This process involves taking two independent


A software SeaChange


Market Analysis By David Fox


SEACHANGE INTERNATIONAL has sold its broadcast server and storage business in a move away from the decreasing margins of what is becoming increasingly commoditised hardware. It will now focus largely on back office systems, video streaming, multiscreen software and targeted advertising systems. SeaChange started revising its


strategy a couple of years ago, after acquiring Eventis, then the market leader in VoD back office software in Europe. It has now become a purely software and services company, “to set ourselves up for growth and sustainability in the future,” said


Harry Koiter, VP EMEA Business Development, who used to be with Eventis. “It is quite hard to have a hardware


All change: Harry Koiter sees cloud on horizon for SeaChange


business if your focus is not there anymore.” The divestment of its storage and server business mainly involved its operations in China, and nobody is losing their job under the new owner, Vantage Point, an investment company. “The business [named XOR Media] is definitely not dead, but for SeaChange it is non core, so it is a natural step. Being a software and services company will definitely see an overall improvement in margins in the next 18 months,” he said. “We still need hardware for our solutions, and will be working with partners for CDN, transcoder tools and DRM. This allows us to create an ecosystem around our software where we are mostly a systems integration or


User experience counts: SeaChange’s new Nitro running on an iPad


hosting company. From there we can make a leap to the Cloud.” One of its services is cloud- based. “We don’t necessarily need to have installations or operations.” Indeed, he is seeing many new entrants, broadcasters and others, who don’t want to invest in infrastructure and prefer to have their operations in the Cloud, although it is also selling its systems to operators for running on head ends.


HD-SDI video feeds, which are 1.5GB each, and combining them into a single 3G (3GB) transport stream, part of the SMPTE-425M specification. On the receiving end, another SMPTE-425M-compatible device demultiplexes the signal, providing two independent HD-SDI video signals. Several other challenges arise


when dealing with 3D video production. When it comes to realtime 3D output processing, the device of choice must accept independent left and right SDI image signals then output, for programme or monitoring, in side-by-side or over/under modes on a single SDI cable. Monitoring on HDMI can be done in side-by- side or over/under modes, or better yet, in frame packing mode on HDMI 1.4a which displays the image in full resolution. Analysis modes such as


anaglyph, difference and 50/50 are great tools for alignment and advanced monitoring. These modes are ideal to see the magnitude of the disparity between both cameras while positioning rigs and validating


Charles Amyot: ”When it comes to realtime 3D output processing, the device of choice must accept independent left and right SDI image signals”


shots. To verify that the footage will be adequate for post production work, other advanced processing such as horizontal image translation controls, including sub-pixel convergence and divergence settings, can be used for slight adjustments or preview. To accommodate mirror rigs, which typically involve an inverted camera, vertical and/or horizontal flips as well as pixel- based vertical offsets are required. For 3D workflows where


cameras are not synchronised, a video frame synchroniser is necessary. After defining one of the video inputs as the reference source, time base correction is applied to the second video input. Both video streams are then output in sync.


“The way we see the Cloud is


to reduce one-off costs and attract customers we couldn’t get in the past. It sets us up for growth mainly in the OTT space,” where he wants to enable customers to take the next step in multiscreen video, increasing revenue and “take the content store seriously”. Part of this will be through


targeted recommendations, promotions and advertising around the multiscreen content. SeaChange started with advertising technology (for linear and on- demand ad insertion) in 1994. It will do this through Infusion, a new product that offers much more effective advertising in a multiscreen system. Other key new products are:


Adrenalin, a multiscreen back-office system that can be run in the Cloud; Affinity, its new social media system; and Nitro, which gives a consistent consumer user interface across every type of screen. www.schange.com


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