SDI Titler Card with Extended Software.
Stream Alpha cards and the Alpha Pro 2.0 software can be use in a wide range of applications:
- TV programs titling during editing and live broadcasting;
- TV program logotypes production;
- automated screening of current time, temperature, atmospheric pressure, and other similar information (additional equipment required);
- audience telephone polls during live broadcasts (additional equipment required);
- informational and graphical design of sports broadcasts;
- generation of various digital and analog clocks and timers;
- pre-scheduled broadcasting of informational and advertisement blocks;
- animation and video clips playback (in 4:4:4, 4:2:2, DV type 2, and AVI formats);
New Stream Alpha SDI has become a multifunction video card, which can replace several studio devices. Apart from main function of superimposing graphics over the passing digital SDI signal or its playback for an external mixer, this video card can be used as transcoder between analog and digital SDI video signal formats and single frame or clip grabber.
Stream Alpha SDI video card is working with 8 and 10 bit serial component SDI input signal and 10 bit output signal, in full compliance with CCIR656 and SMPTE259m recommendations. In the course of signal passing through the card all control information is intact, sound packs may be either left intact or changed, depending on conditions required. The input signal is checked for errors with checksum calculation by the EDH method. For the output EDH packages are formed anew according to SMPTE165 recommendation.
The card works in external input signal synchronization mode. If only computer graphics is played back, then the Black burst synchronization signal can be fed either to the main input or to the optional analog input. In case of absence of external synchronization, the built-in generator is used.
For using the described devices with an external mixer with DSK (Down Stream Key), the output of the key signal (alpha channel) in analog and digital formats is provided. The card setup utility enables setting both positive and negative key signal delay with respect to graphics playback over a wide range.
On computer switch off or if BYPASS mode is on for all devices, input and output are interconnected through the relay, the 75 Om load being switched off. When computer power is switched on and in the course of initialization the passing signal is in no way distorted at the output.
The new model enables displaying the input video signal and the result of its mixing with computer graphics on the computer monitor in real time.
Computer graphics buffer
Video card memory buffer for computer graphics output is 720 x 576 points for 50 Hz video systems and 720 x 240 for 60 Hz video systems. Each point possesses a 32-bit representation, of which 24 bits represent its color (16 million hues), the remaining 8 bits being employed for representation of one of 256 grades of transparency (alpha channel). Though a computer graphics point color component is represented by 24 bits (8 x 8 x 8), in mixing the 30 bit representation is used (10 x 10 x 10), i.e. if the input signal has 10 bits, it will remain the same at the output.
Memory used for graphics buffer and PCI bus bandwidth of the modern computers makes it possible to update its contents in real time, without frame dropping, while transmitting uncompressed video (32 bit/pixel) together with the sound. Sound can be included in output signal in SDI format and be played through computer sound card simultaneously. All this makes it possible to use video card for broadcasting not only soundless titles and logos, but also full-screen slips with sound. This does not require using a have separate video station with offline editing card for that, all output is performed through a single card from a single computer. It simplifies overall switchboarding and ensures simple and reliable broadcasting automation.
Chroma key is another way of defining mixing proportions, when individual mixing proportion with computer graphics is set up for individual color groups of a video signal. Moreover, if only 12 bit (4 x 4 x 4) color space was considered before, which only allowed rough determining "cut-out" areas, at present its dimensionality is 24 bit (8 x 8 x 8), which, together with semi-transparent mixing, ensures very high precision at video signal and computer graphics borders that have now stopped "boiling". If the passing signal has high noise level, a mask on the lower bits in its digital representation can be used.
Signal format transcoding
Stream Alpha SDI video card apart from the serial digital input has analog YUV/RGB, S-Video, Composite inputs. It can form analog YUV/RGB, S-Video or Composite output signals simultaneously with SDI signal regardless of the input used (only one optional composite output was available before). Input signals may be in PAL, SECAM or NTSC, output ones in PAL or NTSC only. Frame rate does not change, i.e. NTSC can be obtained and converted from NTSC only.
Input decoder distinctive feature is 9 bit signal processing, as well as brightness and color component separation in composite PAL, SECAM and NTSC based on band split adaptive filter <> (rather than a rejector filter as before). It does not entail brightness channel pass band narrowing. 9 bit signal processing enables maintaining in numeralization all 256 brightness range values, rather than only 160 - 170 values as in the case of 8 bit signal processing.
10 bit digital-to-analog converter with 4x oversampling is used for analog signal shaping at the outputs. This enables complete signal filtering from high-frequency noise without additionally reducing the output signal brightness channel pass band.
Single frame and video clip capture
Stream Alpha SDI can effect capture from any of its inputs: Composite, S-Video, YUV/RGB or SDI. The latter is especially important since input signal component 10 bit depth is conserved. The video card enables capturing video clips to hard disk or computer memory in real time without compression and dropped frames. Such SDI/YUV/RGB grabbers are very rare and can be very useful in video production offline editing, for video slow replay or storage of images. With 2 such cards it is possible to create video delay line for a few seconds or even minutes.
Additional video image processing and open architecture
The card has a powerful general-purpose Phillips Trimedia processor and memory for program loading. It means that, without physically changing the card, new opportunities can be obtained through upload of micro programs of "virtual" logical elements operation. Moreover, it is not only card logical structure that can be changed, but the very algorithms of video processing as well.
For example, it is possible to:
- add compressed image processing options
- add input signal motion "tracing" program, which is actually used in security and supervision programs developed for security systems
- trace domain of connectivity in chroma key setting
- apply textures in real time, using input image, etc.
Alpha Pro 2.0, operating in Windows 98/2000 media enables creating scenarios (title sequences to be output with various effects) and play them back through the device for computer graphics superposition over TV/video signal. From the user's point of view it resembles a multi-window text processor, in which several scenarios can be edited and kept ready for output simultaneously. Besides, the same scenario can be opened in several separate windows, which simplifies text changing procedure in its various parts.
A scenario is paged, number of pages being unlimited. An individual video effect is related to every page determining its appearance, motion and fading out from video screen. The following effect types are supported: vertical text moving from bottom to top, Drum, Roll, infinite page moving horizontally from right to left (Creeping Line), Crawl, static page Cross Fade with a pause for display, Wipe, including user-defined, with adjustable transition softness, animation playback over static pages, effects with operating areas restricted to a certain part of the screen, animation symbols in Roll or Crawl pages. User-defined parameters for video effects are application area, speed and delay duration.
Alpha Pro 2.0 extended version provides for object management be external applications, including user developed programs. That comprises programs written in Microsoft Office VBA script language, including Word, Excel and Access scenarios, programs in Visual Basic, Web-pages containing scenarios in VBScript, and programs written in Delphi and Visual C++. That enables the user to play back the required pages at the required moment with program modifications in the course of playback (for real-time presentation of any information input to the computer). If computers with video cards are connected into a network, centralized output control from one program is possible.
Broadcasting arrangement design is set up in the form of templates that may be prepared beforehand and/or edited on air. Real-time data are merged into the template immediately at the playback moment. A function is provided for automatic screen update synchronously with input data updates. A system of any capacity may be constructed out of standard equipment (IBM PC, video cards) and can be reconfigured if necessary. The user edits templates as desired and if necessary can write his own Visual Basic, VBScript or VBA programs for his specific tasks.
Using VBscript language in-built in the Internet Explorer it is possible to concentrate program control within one or several HTML pages comprising text boxes and operation buttons. For example, the textbox Surname and two buttons, Show and Hide. Through writing the appropriate scenario and preparing Alpha Pro page templates it is possible to set exactly the design style (background, font for surname display) and effects for its appearance and fading out. That way we get the control panel without distracting foreign control elements.
Having prepared page templates based on broadcast design style and written the management scenario in Visual Basic, it is possible to broadcast appropriate pages at the right moment making software changes directly at the moment of broadcasting (for real-time presentation of any input data). It solves the design problems of sport translation, game shows, etc. The same approach enables telephone polling broadcasting by installing required amount of modems into the computer or using a dedicated card for the purpose.
With a high-precision time-code source in SMPTE/EBU format it is possible to program schedule of page broadcasting time specifying calendar functions and precision up to one frame, which enables automated airing simple commercial inserts (creeping line, logo, animation logo). User interface (HTML page) can be tailored by yourself so as to exclude all incidents in the course of broadcasting, keeping strictly necessary functions only (title text choice from the list, broadcast title, hide title).