Video Digitization and Editing: an Overview of the Process

Video Digitization and Editing: An Overview of the Process

Vinod Kumari Sharma, RK Bhatnagar & Dipti Arora

Abstract

Digitizing video is a complex process. Many factors affect the quality of the resulting digital video, including: quality of source video (recording equipment, video formats, lighting, etc.), equipment used for digitization, and application(s) used for editing and compressing digital movies. In this article, an attempt is made to outline the various steps taken for video digitization followed by the basic infrastructure required to create such facility in-house.

1. INTRODUCTION 2. ADVANTAGES OF DIGITIZATION Technology never stops from moving A digital video movie consists of a number forward and improving. The future of media is of still pictures ordered sequentially one after constantly moving towards the digital world. another (like analogue video). The quality and Digital environment is becoming an integral playback of a digital video are influenced by a part of our life. Media archival; analogue number of factors, including the number of audio/video recordings, print media, pictures (or frames per second) contained in photography, microphotography, etc. are the video, the degree of change between slowly but steadily transforming into digital video frames, and the size of the video frame, formats and available in the form of audio etc. The digitization process, at various CDs, VCDs, DVDs, etc. Besides the stages, generally provides a number of numerous advantages of digital over parameters that allow one to manipulate analogue form, the main advantage is that various aspects of the video in order to gain digital media is user friendly in handling and the highest quality possible. manipulation of data using minimum man and Digital video has several advantages over machine (system) time. With the evolution of analogue video: digital technology, time required on editing of one hour cine-film in analogue form has t Flex i ble interactivity reduced from weeks to few hours. Moreover, t Easy to edit the creativity can be extended to any limit t Mul ti ple cop ies with out qual ity loss within no time for better and better output t Easy to ma nip u late which may not be possible while working with t Ease of use in ad di tional features (ti tling, analogue media. Latest video editing software vi sual mixing, sound inser tion, ed it ing, packages and systems have made the spe cial ef fects, tran si tion, etc.) complex and complicated video editing simple t Trans mis sion through e-mail and easy. t Video conferencing

DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5) 3 t Can be used as an impres sive way of The analog video signal is normally in for ma tion dis sem i na tion ef fec tively on web transferred through an S-Video (or composite sites/multi me dia programmes. video) cable to the input of a digitizer board or Qual ity of digi tal video output depends to an AV machine with a built-in digitizer. The upon var i ous fac tors such as the source video hard disk speed, whether the hard disk is as Betacam, U-matic, Hi–8. These can give internal or external (an internal hard disk better quality than VHS record ing. Some time generally has a faster connection to the rest must be in vested to find the best set tings for a of the computer), and the speed of the par tic u lar video source. Fur ther more, the best machine and the digitizer board inside the settings for one partic u lar video source may machine will determine the possible number not neces sar ily pro duce the best re sults for a of frames per second and picture size of the dif fer ent video source. movie. Before starting digitization, the hard disk 3. VIDEO DIGITIZATION PROCESS should preferably be defragmented and the Steps of video digitization are as follows machine should be booted in a minimal (Fig.1& 2): system configuration (in particular, network (a) Capturing the source video software should be off). There are software utilities, called disk optimizers or (b) Editing the captured video defragmenters that defragment a disk. For (c) Assembling of edited video best system performance, one should (d) Special effects like titling, transition, etc. defragment the hard disks periodically. (e) Sound effects, narration, speech, The video capturing software chosen commentary, music insertion, etc. should provide at least few features, like start (f) Compression and final output. and stop recording during editing, style titling, sound effects, transitions, audio insertion,

Source V ide o Analog Video

Video Captur e Card

Computer (Editing Software)

Test Run

If, No Sati sfie d?

If , Ye s

Burn the CD

Figure 1. Flow chart rep re sent ing the video ed it ing pro cess

4 DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5) Shooting/Re cor ding Capturing Har dware Editing Output

Figure 2. Video editing setup compression and output in required file further video editing. Image quality of the formats. captured video can be improved by changing the following parameters: 3.1 Capturing Source Video t Video bit rate The process of creating a movie starts with t In put fil ter/sharp ness capturing source video clips. Before capturing, spend some time to decide which t Using S-video out put. part of the video is to be digitized, better note 3.2 Editing of Video down the approximate counter reading of the There are two types of video editing: source player. Connect the source to the digitization machine, and establish the t Linear editing digitization parameters within the appropriate t Non-linear editing program. We can set the desired frame rate In linear editing, the editing is performed and picture size according to the desired directly from one tape to another. In this case, output quality. If audio components are not PC only controls the source and recorder. In required, one can turn off the audio non-linear editing, sequences to be edited are component, so that any audio contained in transferred back to tape. Here the video the source video will not be digitized. To capture card transfers the video to the PC’s digitize the video, one starts recording in the hard disk and the editing is then performed capturing software program (for example, entirely within the PC. Pinnacle Studio MP10 (fig 3), Adobe Premiere, etc.). Once the source video Normally, editing involves few or all of the frames are captured, these are ready for following steps: t Working with video scene t Open ing the cap tured video t Re viewing video scenes in the al bum t Trimming scenes t Split ting clips t Com bining and sub di vid ing scenes t Re-detecting scenes. 3.3 Assembling After opening the captured video, we may review the scenes and make adjustments before placing them on the video track. we can decide to combine, split or detect new Figure 3. Editing screen of studio scenes within specific scenes. MP 10

DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5) 5 One can select and/or combine the best background music, recording voice-overs, video frames or can drop unwanted frames. and inserting audio effects such as applause, bells, seawaves, etc. Such sound effects can 3.4 Special Effects be picked up from clip art gallery supplied Videos can be made more impressive by with editing software. A huge number of using features like transitions, titles, sound pre-recorded or created sound effects are effects, etc. available as sound files in clip art CDs. Similarly the music audio files stored in hard 3.4.1 Titling disk in sound file format can be inserted along ‘Titling’ is an integrated title editor program with the videos or we can import audio of the editing software that allows quick and directly from an audio CDs. In addition, the easy creation of professional quality titles and audio track of all video clips is captured along graphics. Titles can contain words, shapes, with the video, and is always available which background colors, and photos or graphics can be manipulated according to the visual imported from other programs. This feature demand. offers a preset, professionally developed Voice-overs and other audio can be styles for quickly making titles, along with recorded into the movie directly from virtually endless custom styling. Titles can be computer, (any length and type of background modified by adding transitions for a wide music can be inserted). variety of effects, such as, fading in sliding, and adjusting duration of the title appearing in Audio clips are selected and placed on the movie. Overall the title should be their tracks in the same way as video clips. informative, describing the contents of the Once an audio clip is placed on its track, it movie and awaken interest. can be edited in the same way as a video clip like play duration, volume adjustment, 3.4.2 Adding Transitions trimming, beginning or end, dissolve, fade-in, Transitions are used according to the fade-out, etc. content of the video. Properly used transitions subtly reinforce the meaning of the movie and 3.6 Video Compression how it plays without the audience becoming Video compression is the process of aware that a transition is used. In reducing the file size of digitized video by professionally produced video on television, removing the redundancy. To reduce the one can see many ways to improve tapes. amount of space needed to record or transmit Generally, it is advisable to refrain from the information, compression is a must. overusing transitions that tend to cause Uncompressed video and audio data take a abrupt changes or otherwise draw attention to lot of memory. PAL (Phase Alteration by Line) themselves. There is a big difference between has a resolution of 768X576 pixels and is a subtle dissolve from one clip to the next, transmitted at 25 (full) screens per second. and employing a heart-shaped wipe. Thus one second of PAL video requires 768X576X25X2 bytes, that is approximately 3.5 Working with Audio 22MB. This means that 30 seconds of While appropriate music can add touch to uncompressed video will fill up a CD (650 a movie, a professional finishing and can do a MB). 30 seconds of CD-quality audio would lot to reinforce the message of a video. The amount to 176 KB. Reducing the video music selected, however, should always be resolution to one-fourth (SIF) or even appropriate to the massage of the film. This is one-sixteenth of full resolution would still sometimes a time consuming matter and a result in a data stream of more the 1 MB. challenge, but it is worth the effort, since well The technology by which video chosen music is usually greatly appreciated compression is achieved is known as a by the viewer. A great deal of polishing and ‘Codec’ an abbreviation of compression/ depth can be generated by adding decompression. ‘Codecs’ can be

6 DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5) implemented in hardware and software or a TV cards and graphic boards with a video combination of both. Hardware codecs are input also use AVI format. These are able to generally more powerful. They are used to grab video clips at lower resolution (mostly compress multimedia files for transfer and 320X240 pixels). The compressed video files storage and then to reverse the process for are ready for playing, saving on CD, sending playback. Codecs are constantly being via e-mail, using on web, inserting in upgraded for higher compression without multimedia presentations, etc. loosing quality during playback. In plain terms codec is just another module of the 4. TIPS FOR VIDEO EDITING multimedia control interface (MCI) and the t Do not string together scenes in which MCI makes it available to other software. cam era is mov ing. There are number of audio compression t Di a logue should al ways be shot al ter nately codecs and video compression codecs. from vary ing an gles of view. For compression, streams of symbols are t Make cuts when per sons are in mo tion. transferred into codes. If the compression is t Make harmo ni ous cuts, avoid vi sual effective, the resulting stream of codes will be disjunction. smaller than the original symbols. Video is t Shots with less movement should be of compressed using a process called variable shorter dura tion and shots with fast bit rates encoding which allots a changing move ment can be lon ger. number of dots to enhance resolution in a t Long shots have more content, so they given scene. Scenes with lots of light or little should be shown lon ger. action require less bits than dark scene or t Do not edit a video file after compressing it those with lots of action. The case where as the editing process may cause information is relayed more efficiently and degradation of the video data. recovered exactly as it was before compression with no loss of fidelity is called ‘lossless compression’, as opposed to lossy 5. BASIC SET UP FOR VIDEO compression, in which same information is EDITING irretrievably lost during encoding, decoding Minimum System Configuration: process. Lossless compression discard only m Intel Pentium 133 MHz or equiva lent redundant information. The higher the proces sor compression ratio, the worse the resulting m Windows 95 or Windows 98 OS image. m VGA card, DirectX 5.0-compatible; 256 Some compression formats are; AVI, colour minimum MPEG, CINEPAK, IVI, INDEO and RLE. m At least 32 MB of RAM Different compressors are capable to m Hard disk with sufficient free space for compress the data from 2:1 to 200:1. studio software and MPEG files (30 MB to Commonly used formats are AVI and MPEG. install software, and 100 to 300 MB for The MPEG file format is supported on all every 10 minutes of captured Windows 95, 98, NT. In some instances, one audio/video) may wish to output the movie in AVI file m CD-RW drive format. Generally AVI files are larger and not m Parallel interface support for ECP or of as high quality as MPEG files. There may EPP-mode be two reasons for using AVI format because m Sound card, DirectX 5.0-compatible one may require importing the video into the m Speakers application that doesn’t support MPEG files or some viewers will be running Windows 3.1. m Microphone to record voice-overs m Video capturing card (internal or external) Despite its age and numerous problems, with latest video editing software. the AVI format is still used in semi-professional video editing cards. Many

DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5) 7 Video Equipment: depends on the application where the final m Any source with a composite or S-video edited video files are to be used. Commonly output (e.g. camcorder, VCR, laser disc, used formats are ‘AVI’ and ‘MPEG’. But, now or TV tuner) a days ‘dat’ format is widely used. Video is a very important part of 6. CONCLUSION multimedia presentation as it gives In digital media, the creativity can be effectiveness to the show. A lot of video extended to any limit within no time for better editing software are available in the market. output. However, few factors certainly effect Let us hope, in future, we will have more and the final outcome, like availability of free more video editing software which will give space on hard disk, defragmentation, and more flexibility in editing to make our video RAM, etc. There should be sufficient space in more impressive. the hard disk, it should be defragmented It is hoped that the topic discussed in this frequently, and minimum RAM should be 128 article will be well received and critically MB. examined by other experts in the profession. Adding effects like transition, titling, etc., Possibly some useful comments will be give realistic beauty to the video. The file forthcoming, so that in due course of time format chosen is very important, but it also good amount of literature is available to us for

Contributors: Smt Vinod Kumari Sharma is Scientist D at Defence Scientific Information and Documentation Centre (DESIDOC), Delhi - 110 054. Shri R K Bhatnagar is Tech Officer ‘B’ at DESIDOC, Delhi - 110 054. Smt Dipti Arora is STA at DESIDOC, Delhi - 110 054.

following new and up-to-date methods for video digitization and editing.

8 DESIDOC Bulletin of Inf Technol, 2002, 22(4 & 5)