Non-linear editing in the digital television programs Application Analysis

Abstract: With the non-linear editing system in the field of radio and television universal application, bringing radio and television practitioners faster and more efficient production processes and ways of working, non-linear editing systems are widely used in film and television program post-production. Author combines practical work , discusses the technology in the digital video non-linear editing the position and its application.

Keywords: nonlinear editing digital video program production system construction

In the late 20th century, with the rapid development of digital technology, is widely used in nonlinear editing video post production. Nonlinear editing mainly refers to the various types of computer-centric information consisting of video and audio editing; refers to the acquisition program to your computer directly from the computer's hard drive in order to frame or papers quickly and accurately access the material for editing mode; was able to randomly access any material from material storage time, interval limit edits. Broadly speaking, nonlinear editing digital video programming techniques can include: video material available, the synthesis of video objects, video clip editing, video effects generation, painting and color adjustment, six aspects superimposed subtitles in non-linear editing systems , the most important is the inclusion of animated models, digital effects and multi-synthesis and other functions, enabling the system to become non-linear editing film and television production to fully play its creativity and imagination of the technology platform papers download.

Construction of a non-linear editing system

Non-linear editing system is mainly used in broadcast television production units and all kinds of advertising and it is dominated by computer platform (including video and audio processing cards, professional graphics, three-dimensional special card, etc.), high-speed large-capacity hard drives, audio and video input and output devices, monitors and other hardware devices, and with the corresponding non-linear editing software.

1.1 System hardware mid-1990s, non-linear editing and began to appear in our country has been applied in non-linear editing system, the most essential point is that the digital signal is processed by the system, such as non-digital signal input system is required for A / D conversion, the use of digital technology into the computer's hard drive, and use editing software program production operations on the computer, the operation due to non-linear editing system data storage capacity of the hard disk is limited, rather than broadcast television signal data compression is very large, if QPSK modulation is used, the required transmission bandwidth above 100 MHz, so the image quality requirements should be based on the original signal corresponding compression greater the compression ratio, the input image signal can be more, but the image quality is also worse.

1.2 System Software nonlinear editing system software for the non-linear editing system provides a GUI (Graphical User Interface) and network management features such as bone, can also be used to complete the video clips, subtitles superimposed, 3D animation, digital effects, audio production, color rendering, etc. complex editing. now the world's many different types of non-linear editing software, you can put them according to their functions into two categories: the first category: special type of software, hardware settings for the specially developed, they can be called directly nonlinear card Set hardware stunt stunt card or specialized hardware stunt stunt or a short time to form a real-time generation of special effects, thus greatly accelerating the speed of the program to edit the second category: Universal software, general purpose software mostly not directly comparable to non-linear Editing boards anchored for input and output, but can be entered on the hard disk array has audio-visual material for processing, processing and editing, or make your own two-dimensional or three-dimensional images and video clips to those synthesized by the input output software output.

Two non-linear editing technology and its application

2.1 video material to obtain three-dimensional scanner or camera angle shots of objects of different photo as the three-dimensional model parameter input to Image Modeler software, the software will calculate the object through the polygon mesh frame; Then the user based on this framework to produce three-dimensional model ; the 3D model built, the optical capture system (MotionAnalysis) from the actual shooting of the scene to extract the motion parameters, the input to the Match Mover software in order to achieve the effect of three-dimensional animation; Finally, in order to make the effect more realistic, using Phoenix Tools for MAYA software to render the whole animation.

2.2 Synthesis of a video image digital video includes the following four technologies:

2.2.1 multi-layer stack of the multilayer video objects (images, text, graphics, and animations, etc.) superimposed together, stacking mode can be opaque or partially transparent in the multi-layer stack, each layer different from the priority level of the video object, displayed on the screen of the outermost layer of the highest priority, the more inside the lower priority level. each video object can also conduct their own special treatment, such as rotation, scaling, filtering and so on.

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2.2.2 Health effects chroma key color in the foreground is the first video object cutout from one color (usually blue), this process is called a mask (Mask) generation process in the mask, the video object within each pixel a = 1, for each pixel outside a = 0, by a value of the foreground and background synthesis, a = 1 is displayed in the foreground of the video object , a = 0 is displayed in the background, resulting in the foreground and background video object cutout synthesis results, this technique can be used for virtual studio.

2.2.3 The foreign key is used to select a portion of the video image superimposed. The mask saved as a separate image file, and the image is applied to any video image, and then select a value that is displayed in a = 1 a video image at a = 0 Department is shown another video objects.

2.3 video clips and video clips stunt generated by nonlinear editing software, you can conduct video clip editing, wipe, move, replace, insert and overwrite operation, in this process, the production staff may need to add video effects. The most commonly used video effects are fade, wipe, fly, like, page curl, flip, etc. With the development of computer graphics, three-dimensional effects are increasingly being used and it is mainly through the simulation of natural light, method using the shaded surface, transparent, light tracing method, the texture image is generated, so that the two-dimensional image generating three-dimensional effect.

2.4 color correction and color correction that is superimposed captions for digital image chrominance signal processing. Subtitles superimposed hardware and software are divided in two ways. Subtitle software is to use the principle of mapping software as the subtitle graphics processing, import it to edit Rail-to-keying a layer image mapping, complete subtitle function; hardware subtitles usually consists of a graphics accelerator and a graphics frame buffer composition, graphics accelerator is mainly used for a single pixel, pixel and the pixel group dedicated graphical components such as management, It has a drawing lines, arcs, and high-level graphics display module. superimposed subtitles is the process of character font from the hard disk in the computer's memory transferred to the linear address into graphics frame buffer, the attribute describes the output to video mixer and outputs the synthesized video image.

2.5 the output of the digital video editing software is the current linear uncompressed digital video processing circumstances, huge amount of data, therefore, have a lot of non-linear editing software audio compression encoding, the edited program Fast compressed into MPEG-1/2/4, M-JPEG and other encoding format output, thereby greatly reducing the amount of data stored to suit different applications.

3 new developments in non-linear editing techniques

Studio production involves a large number of programs for encoding compression processing, such as splicing between different programs, add subtitles on the screen, logo and other effects. Present, due to non-linear editing systems use the studio for not compressed video signals editing program production method, which requires the storage of the compressed image and editing the non-compressed image format conversion between not only increases the amount of, the codec will be caused due to the resulting image and quantify the degradation in this case , people need to be considered directly in the compressed domain for editing digital video, thus speeding up the television program production, distribution, storage, transmission and broadcast integration process.

4 Conclusion

Digital TV systems increasingly accelerated pace of development, computer technology gradually penetrate into all areas of radio and television. Nonlinear editing technology has undergone many years of development, its hardware and software technology matures. Meets high-end film production lifelike dazzling special effects needs but also to meet the low end of the news clips produced. nonlinear editing systems function more perfect, in the broadcast television industry will occupy an increasingly important position as a sunrise technology, its applications will usher in a glorious era.

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