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Originally featured on BroadcastEngineering.com
Mar 11

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3/11/2009 1:24 PM  RssIcon

q-down123-a-afd.jpgCrystal Vision has released a new version of its popular down converter and distribution amplifier. Q-Down-A-AFD combines flexible outputs and a unique level of image quality in its price range with the ability to use the SMPTE 2016 AFD data embedded in an HD video input to automatically select the appropriate aspect ratio when down converting.

Q-Down-A-AFD’s flexible output combinations make it suitable for a large number of applications, whether the broadcast engineer needs an HD distribution amplifier, SDI distribution amplifier, HD to digital SD down converter, HD to analog SD down converter, or Standard Definition D to A. Q-Down123-A-AFD gives two reclocked loop-throughs of the HD or SD input, while the ‘double decker’ Q-Down183-A-AFD gives eight loop-throughs. Both versions additionally provide three Standard Definition outputs individually link selectable between analog and digital, with the analog video configurable as composite, Y/C, YUV or RGB. One of the loop-throughs can alternatively be exchanged for a dedicated SDI output, further increasing the number of applications.

Q-Down-A-AFD also offers excellent picture quality. Explains Crystal Vision’s Managing Director, Philip Scofield: “We worked hard to get this low cost down converter to be good enough for the major broadcasters to accept for use in their main programme path. We needed to maintain all the sharpness of an HD signal that could be transferred to SD without any of the aliasing caused by trying to pass signals that shouldn’t be there. We also wanted to offer a short processing delay of just 16 lines to avoid the requirement for matching audio and video delays in the system. The results are outstanding, and the engineering ranks as some of the best carried out by Crystal Vision.”

Q-Down-A-AFD is ideal for those working with embedded audio. With an HD input it will de-embed the two groups of audio, converting them to the appropriate format before re-embedding them into the digital SD output. With a Standard Definition input it will pass two groups of embedded audio transparently to the digital SD output. Other notable features include a variable video delay of up to one video frame, adjustable in one line steps, allowing it to match other equipment delays in the system, and signal probe functionality which makes it useful for flagging up faulty signals, especially in multi-channel applications.

Q-Down-A-AFD has been designed for use in those HD installations which use SMPTE 2016 data to describe a source’s Active Format Description (AFD), causing a following down converter to output the Standard Definition with an appropriate aspect ratio conversion. HD programmes are often made of a mixture of true High Definition sources and SD sources that have been up converted and have black pillars at the sides, and when the HD signal is originated from Standard Definition it is necessary for the down converter to behave differently. When down converting Q-Down-A-AFD will select its output aspect ratio according to the AFD code embedded in the input video, and offers three options for the SD output. With Auto 16:9 mode the SD output can be set to be always 16:9 and in this case it will do the down conversion without ever changing the aspect ratio. Alternatively the SD output can be set to be always 4:3 (Auto 4:3 mode), in which case it will down convert and perform either a Letterbox or centre cut, depending on the source material. There is also a third adaptive option: Auto Adaptive mode. Here, if the HD input is 16:9 full frame the picture is down converted with no aspect ratio conversion and is output as 16:9 SD. If the SMPTE 2016 data indicates that the HD input is a 16:9 Pillarbox, however, a centre cut is performed and the output is 4:3 SD. Widescreen signalling can be inserted into the analog and SDI outputs to indicate the picture format to downstream equipment – either done manually or by automatically following the incoming AFD data. Q-Down-A-AFD makes it possible to have a powerful system with the majority of signals not containing SMPTE 2016 information. With Q-Down-A-AFD it is only necessary to label those HD video signals that are not full frame 16:9 images, so that when an input is not labelled Q-Down-A-AFD assumes that it is a full frame 16:9 – giving the broadcaster an automatic system with minimum effort.

Shipping now, Q-Down-A-AFD is a space-saving 100mm x 266mm module which fits in Crystal Vision’s standard frames alongside any other product from the range, with the flexible control options including PC software.

Based at Whittlesford near Cambridge in the UK, Crystal Vision provides digital keyers, picture storage modules and a full range of digital and analog interface equipment including converters, decoders, encoders, distribution amplifiers and audio embedders to the professional broadcasting industry worldwide.

www.crystalvision.tv

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