Originally featured on BroadcastEngineering.com
11/3/2008 8:32 AM
New from Crystal Vision is SYN HD-AFD – a multi-functional HD/SD synchronizer designed to synchronize incoming video signals, compensate for timing delays within a video system and insert SMPTE 2016 Active Format Description data into the output video for aspect ratio correction by downstream equipment.
Essentially a frame synchronizer allowing any timing difference, SYN HD-AFD additionally offers the advantages of a line synchronizer, with a short minimum delay of 2us and quick recovery of input timing. SYN HD-AFD has two operational modes: synchronizer and delay line. Synchronizer mode is ideal for external sources that are not timed to station references, with SYN HD-AFD taking its timing from the external analog reference and automatically synchronizing sources between 0 and 2 fields, fixing any incorrect frame rates plus any delays. Cross-locking means that an HD or SD input can be referenced to either HD tri-level syncs or SD Black and Burst – allowing SYN HD-AFD to conveniently use any existing timing signals. The output timing relative to the reference can be adjusted through an entire frame using horizontal and vertical settings. Delay mode is ideal for when the frame rate is correct but the source has been passed through equipment such as a chroma keyer and therefore been delayed for a few lines. With full adjustment of vertical and horizontal timing available, the fixed delay can be set between 2us and one frame. SYN HD-AFD offers a powerful synchronizing system, synchronizing at three separate points – the start of the field or frame, just after the switching point, and the start of the active field or frame – which allows it to avoid picture disturbances on input switches.
Not only does SYN HD-AFD have all of Crystal Vision’s well-respected synchronizing features, it also includes the ability to label a signal with SMPTE 2016 data to describe the Active Format Description (AFD), which some HD installations use to allow 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. When the HD signal is originated from Standard Definition therefore, it is necessary for the down converter to behave differently and perform a centre cut conversion. SYN HD-AFD can embed one of sixteen AFD codes into the signal for the down converter to read, with the code describing which areas of the screen contain a picture and which areas are black ‘padding’. The AFD code is contained in an ANC data packet, which is carried in the active portion of a specified line in the vertical blanking.
Explained Crystal Vision’s Managing Director, Philip Scofield: “SYN HD-AFD is a fairly low cost and convenient way of labelling signals with AFD information – not only does it fit in with automation systems, it also allows GPI control. It is especially economic if engineers use it where they would need a synchronizer anyway – when signals arrive from outside the station, for example. Crystal Vision can in fact offer customers a complete AFD solution, with our Q-Down-A-AFD down converter able to read the SMPTE 2016 data and select an appropriate aspect ratio conversion.”
Shipping now, SYN HD-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 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 analogue interface equipment including converters, decoders, encoders, distribution amplifiers and audio embedders to the professional broadcasting industry worldwide.