Clock Station

By Dmitry Repkin

Review contents:

CGs yesterday, today and tomorrow Software and hardware tools for TV programs graphic branding Graphic tools of DMS module system The use of XDR2-GENSEC in the systems of regional air branding Akula VTM video compositing system. New model range — new features Profitt’s titling and air branding systems, clock and logo generators Overview of the systems based on extended version of Alpha Pro software X-CG character generator — good choice for titles creation TitleBox graphic manager Clock Station Leitch’s equipment for air branding Matrox InfonetTV Deko CGs from Pinnacle Systems Company Pixel Power equipment Stream Labs.’s video cards Videoprinter system for DSC video switchers Videonics titling machines

Like many things in TV broadcasting air clock have their specifics. Solving, from one side exclusively functional task — current time display, they must, from other side, be compliant to common design of TV channel branding. Keeping in mind the fact that channel’s design is changing at least two times a year it is necessary that the clock forming system could provide both precision of time displayed and design flexibility at the same time.

Most complicated in terms of design versions of clock are being created using compositing applications and so clock are displayed as video clip they produce a problem of synchronization to real time. It related to that that the clock being a video clip must be rendered for each momentum of time they are displayed in the air. It may take sufficient disk space on the company’s video server. Besides, any change of broadcast schedule leads to need of new change of “in” point for clock’s video clip.

Precision of clock being displayed is extremely important — they must absolutely accord to reference time. TV viewers always wait for accordance of key programs to program schedule and, first of all, news, and many viewers trust screen clock so much that confirm with them their own clock. In fact, incorrect time display will harm TV channel reputation.

Clock Station system was created with respect of requirements mentioned above and is dedicated to forming and output to air the complex image of clock synchronized with real time. System’s flexibility gives designers pretty freedom in forming of unique style with no compromise to synchronization with world time. The system provides audio accompaniment which can be either played back form disk synchronously to video or uses passing through audio signal or mixes these two audio signals.

For video signal forming the Clock Station system uses well accepted Matrox DigiSuite LE card which allows exploiting graphic frame buffer and video clip layer simultaneously. DigiSuite LE card provides high picture quality and allows using both composite and component inputs/outputs. Additional module adds a possibility of using SDI inputs/outputs. Software codec makes it possible to prepare background video on any remote computer with no need of additional card.

Clock image in the Clock Station is being formed from following components:

• Background video clip or passing through video layer;
• Clock plate graphic layer;
• Clock’ hours arrows dynamic layer;
• Clock’ minutes arrows dynamic layer;
• Clock’ seconds arrows dynamic layer;
• Logo or graphics layer placed over seconds arrows.

Arrows in the Clock Station system can be either rotating graphic elements or graphic frames sequence. For each arrow any type can be chosen. The system supports both 12- and 24-hour time display modes.

Centers for arrows rotation can be independent. For rotating hour and minute arrows the possibility to define increment of rotation exists.

Clock types formed by ClockStation system

Special algorithm of full screen antialiasing allows avoiding the comb effect when arrows reach angles close to 90°. In contrast to algorithms of multi-point (most often 4-point) super sampling the method used allows reaching good antialiasing even for such lines which are mostly horizontal which minimizes flicker effect in interlaced scan of PAL/SECAM.

Use of graphic frame sequence for arrows forming gives a possibility to use any kind of images for hours, minutes and seconds values display. It allows emulating digital clock with high degree of reality giving the designers possibility of using any graphic elements (gradient paint, glows etc.) for clock displayed which is often impossible for digital clock software generators that form image “on the fly” using system fonts.

A feature which makes the Clock Station system special is the ability of using the video layer not only for background creation but also for forming of arrows. For example, it is possible to display seconds using video clip with one minute duration in which second’ arrows is animated. Clock Station tracks current time and automatically adjusts a video clip to it.

In the latest version of the system lot of attention is paid to the background video-to-reference time synchronization problem. This specific problem arises upon necessity of playback of previously rendered clock’ video image synchronous to reference time. While output of graphic elements is totally synchronous the speed of video clip playback is locked to external synch generator but not to UTC time. Even high quality synch generators like Tektronics SPG-422 have deviation about 1 pixel/min. With such precision the second’ arrow of previously rendered video clip moving with synch generator defined speed will deviate with reference time for 1 frame per 11 hours. The deviation will be visible when it reaches 4…5 frames — after two days. Unfortunately even such precision is defined only for particular temperatures of synch generator operation and in real world of studio this parameter value may drop down several times. Moreover if TV Company uses less quality synch generators the deviation may appear sooner, possible in few hours. For such cases tracking the Clock Station system was specially enhanced to automatically bypass or add frames for complete synchronization of all image elements to UTC time.

All system’s settings can be stored for further recall which allows upon necessity quickly switch from one clock design to another one.

Clock Station system successfully works on RenTV channel in 24/7 mode.

Material provided by JC System Integration Company