Digital Video Editing

Transcription

1 Digital Video Editing

2 DVD Video Training in Adobe Premiere Pro

3 Video Signals: Analog signals are made up of continuously varying waveforms. In other words, the value of the signal, at any given time, can be anywhere in the range between the minimum and maximum allowed. Digital signals, by contrast, are transmitted only as precise points selected at intervals on the curve. The type of digital signal that can be used by the computer is binary, describing these points as a series of minimum or maximum values - the minimum value represents zero; the maximum value represents one. These series of zeroes and ones can then be interpreted at the receiving end as the numbers representing the original information.

4 Frame Resolution: FRAME PIXEL PIXELS (Picture Elements) is the minimum screen display element, represented as a point with a specified color and intensity level (RGB or YCC). FRAME is a single still image in a sequence of images (Video). FRAME RESOLUTION is the amount of information (PIXELS) in each frame X X 480 Higher resolution will result in a better quality image and more storage required.

5 Width Height Frame Aspect Ratio: The Frame Aspect Ratio describes the ratio of width to height in the dimensions of a frame. For example, the frame aspect ratio of NTSC video is 4:3, and some motion-picture (Film) frame sizes use the more elongated aspect ratio of 16:9. Frame Aspect Ratio :3 16:9

6 Pixels Aspect Ratio: Square Pixels (1.0), DV NTSC (0.9), DV PAL (1.067), Widescreen 16:9 (1.422) etc. Pixels Aspect Ratio: Some video formats use a different aspect ratio for the pixels that make up the frame. When a video using square pixels is displayed on a non-square pixel system, or vice versa, shapes and motion appear stretched. For example, circles are distorted into ellipses. Square Pixels Aspect Taller Pixels Aspect Wider Pixels Aspect

7 24 FPS MOTION PICTURE (FILM) Frame Rate: FRAME RATE is the number of images (Video Frames) shown within a specified time period; often represented as FPS (Frames Per Second) creates the illusion of motion. 25 FPS PAL/SECAM TV SCREEN 2 FPS 5 FPS 8 FPS 12 FPS FPS NTSC TV SCREEN 15 FPS 20 FPS 25 FPS 30 FPS The more frames per second (FPS), the smoother the motion appears and more storage required.

8 00:00:00:00 Hours Minutes Seconds Frames Hours Minutes Seconds TIMEBASE Frame -NTSC Frame -PAL Frame -Film RANGE For example, in a 25 fps timebase, you never see a 25 (00:00:00:25) in the frames part, because the 25th frames is one second (00:00:01:00). Same for Second, Minute, hour and the NTSC, PAL, Film timebase. 00:00:00:00 Non Drop Frame Time Code 00;00;00;00 Drop Frame Time Code Time Code: Timecode defines how frames are counted and affects the way to view and specify time throughout a project. Timecode never changes the timebase or frame rate of a clip or project - it only changes how frames are numbered. Professional videotape decks and camcorders can read and write timecode directly onto the videotape, which lets it synchronize audio, video, and edits, or edit offline using the timecode SMPTE (Society of Motion Picture and Television Engineers). When using the NTSC-standard timebase of 29.97, the fractional difference between this timebase and 30 fps timecode causes a difference between the displayed duration of the program and its actual duration. While tiny at first, this difference grows as program length. Drop-frame timecode is a SMPTE standard for fps video that eliminates this error, preserving NTSC time accuracy. When using drop-frame timecode, it renumbers the first two frames of every minute except for every tenth minute. For example, the frame after 59:29 is labeled 1:00:02. No frame are lost, because drop-frame timecode doesn t actually drop frames, only frame numbers. The 18962th frame in a NTSC fps timebase is 00:10:32:20 The 18962th frame in a PAL 25 fps timebase is 00:12:38:12 The 18962th frame in a Film 24 fps timebase is 00:13:10:02

9 Frame Rate Convert: A 24 fps frame rate clip (one-half second shown here) display in a 24 fps frame rate project. All frames display as expected. A 24 fps frame rate clip (one-half second shown here) display in a 30 fps frame rate project. Some of the frames are repeated. For smooth and consistent playback, the timebase, the source frame rate, and the project frame rate should be identical. In general, use 24 fps for editing motion-picture film, 25 fps for editing PAL and SECAM video, fps for editing NTSC video, and 30 fps for other video type. If the source frame rate and the project frame rate don t match, the system will convert the source frame rate to the project frame rate by repeat or omit some of the source frames. The effect may be distracting or imperceptible depending on the differences between the timebase and the frame rates in the project. A 24 fps frame rate clip (one-half second shown here) display in a 15 fps frame rate project. Some of the frames are omitted. When time system don t match, the most important value to set is the timebase, which you should choose appropriately for the most critical final medium. You ll get the most predictable results if your timebase and frame rate are identical, or are at least even multiples of each other.

10 Interlaced & Non-Interlaced Video: TV NTSC Lower Field First TV PAL Upper Field First Interlaced video describes a frame with two passes of alternating scan lines. A picture on a television or computer monitor consists of horizontal lines. There is more than one way to display those lines. Most personal computers display using Progressive Scan (Non-Interlaced) display, in which all lines in a frame are display in one pass from top to bottom before the next frame appears. Television standards such as NTSC, PAL, and SECAM standards are interlaced, where each frame is divided into Two Fields. Each field contains every other horizontal line in the frame. A TV display the first field of alternating lines over the entire screen, and then display the second field to fill in the alternating gaps left by the first field. Computer Monitor Progressive-scan video describes a frame with one pass of sequential scan lines. 1 Frame = 2 Fields NTSC: frames per second; about 60 fields per second PAL: 25 frames per second 50 fields per second SECAM: 25 frames per second 50 fields per second

11 RED Video Color: RGB RGB: Computer monitor typically transmit color with 8 bits of information for each of the Red, Green, and Blue components. With these 24 bits of information, over a million different variations of color can be represented for each pixel (that is 2 raised to the 24th power). This type of representation is known as 24-bit RGB color. GREEN BLUE YCC: The TV screen uses the YCC color to represents the image. The Y was the luminance signal that was used by black and white televisions, while the C s stood for the color components. The two color components would determine the hue of a pixel, while the luminance signal would determine its brightness.

12 Overscan and Safe Zones: Frame size can be misleading if it s preparing video for television. Most NTSC consumer television sets enlarge the picture; however, this pushes the outer edges of the picture off the screen. This process is called Overscan. Because the amount of overscan is not consistent across all televisions, it should keep action and titles inside two safe areas - Action-Safe Area and Title-Safe Area. The action-safe zone is a margin, about the width of a typical amount of overscan, around all sides of a frame. The title-safe zone is a margin that extends further into the frame than the action-safe zone. The title-safe zone helps ensure that text and important graphics are completely displayed, and avoids the distortion of text and graphics which can occur toward the edges of many television. Always anticipate overscan by using safe zones, keeping important action and text within them, and testing the video on an actual television monitor. Computer monitor Television monitor Computer monitor can show 100% of the frame Television monitor can only show center part of the frame

13 Composite With Audio S-Video With Audio Component Analog Video Formats & Their Typical Connections: Because of the noise, in analog video, the type of connection between devices is extremely important. There are three basic types of analog video connections. Composite: The simplest type of analog connection is the composite cable. This cable uses a single wire to transmit the video signal. The luminance and color signal are composited together and transmitted simultaneously. This is the lowest quality connection because of the merging of the two signals. S-Video: The next higher quality analog connection is called S-Video. This cable separates the luminance signal onto one wire and the combined color signals onto another wire. The separate wires are encased in a single cable. Component: The best type of analog connection is the component video system, where each of the YCC signals is given its own cable. Typically, the higher the quality of the recording format, the better the quality of the connection type. TAPE FORMAT VIDEO FORMAT QUALITY APPROPRIATE APPLICATIONS Video-8, VHS Composite Good Home Video S-VHS, Hi-8 S-Video Better Prosumer, Industrial Video BetaSP Component Best Industrial Video, Broadcast

14 IEEE 1394 is also know as FireWire (Apple Computer) and i. LINK (Sony Corporation) Digital Video Formats & Their Typical Connections: DV25: A prosumer-targeted variation on the theme is called MiniDV and Digital8. They offer the same data rate and color sampling as DV25. Sampling is 4:1:1. DVCAM and DVPRO: The basic DV format was designed for the consumer marketplace. Sony has introduced a professional variant known as DVCAM, which uses the same compression and tape as DV, but records less video on each tape. Recording is accomplished by magnetizing very small sections of videotape with differing polarities. Both the DVCAM and DVCPRO systems are designed with the professional in mind and each offers distinct benefits for a particular customer type. DV50 and DV100: In addition to the DV25 standard, there are also emerging standards known as DV50 and DV100. Since DV25 indicates 25 Mbits/sec of video, DV50 indicates 50 Mbits/sec and DV100 represents 100 Mbits/sec. The DV50 standard uses 4:2:2 color sampling and a lower compression of 3:3:1. The video quality of this standard is extremely high, and is suitable for the most demanding professional broadcast purposes. The DV100 format will be used for HDTV (High Definition Television) recording. Digital Betacam: Also known as DigiBeta, Digital Betacam is the high-end broadcast professional's choice. It provides superior image quality, and the high-end equipment required to work in this format is commensurately costly. Analog Betacam SP tapes can also be played back in DigiBeta decks. DV FORMAT DV25 (MiniDV) QUALITY Good APPROPRIATE APPLICATIONS Home/Prosumer Video, Web, CD-ROM, DVD DVCAM, DVPRO Better Prosumer, Industrial Video, DVD DV50, DV100,DigiBeta Best Industrial Video, DVD, Broadcast

15 NTSC: National Television Systems Committee PAL: Phase-Alternating Line SECAM: Sequential Couleur Avec Memoire Broadcast Standards: There are three television standards in use around the world. These are known by the acronyms NTSC, PAL, and SECAM. If you begin producing content for international consumption, or if you wish to incorporate foreign content into your production. You can translate between the various standards, but quality can be an issue because of differences in frame rate and resolution. The multiple video standards exist for both technical and political reasons. BROADCAST FORMAT HORIZONTAL LINES FRAME RATE PIXELS ASPECT COUNTRIES NTSC 525 Lines fps 0.9 USA, Canada, Japan, Korea, Mexico etc. PAL SECAM 625 Lines 625 Lines 25 fps 25 fps Australia, China, Most of Europe, South America etc. France, Middle East, Much of Africa etc. The SECAM format is only used for broadcasting. In countries employing the SECAM standard, PAL format cameras and decks are used.

16 IEEE 1394 Card Analog Capture Card Real-Time Editing Card Getting Video Into Your Computer: IEEE 1394 Cards The simplest kind of card available is the IEEE 1394 interface card. This card does not support any analog video I/O, compression, or special processing. In fact, it does not really capture video, it merely enables the transfer of digital video into your computer. The IEEE 1394 interface can be used for many other connections as well, such as hard drives, scanners, and networking. Analog Capture Cards Analog capture cards actually perform the task of converting analog video to and from digital video. There are many different sources of analog video, including VHS tapes, Hi-8 cameras, Beta-SP tapes, etc. These cards vary in price depending upon the type of analog interface supported. Real-Time Editing Cards When you do editing a video, a special effect like a transition would make you wait while it calculated the effect, whereas the high-end system included specialized hardware to create it instantly. Sometimes the calculation of the effect (Called Rendering) on the desktop system could take minutes or even hours, which would slow production to a crawl. This productivity barrier between the high-end and the desktop has now been shattered by a variety of newly introduced Real-Time editing cards. These boards have specialized processors to handle the enormous number of calculations required for video effects.

17 File Formats: Graphic: Vector or Bitmap still picture. Color Depth - 8, 16, 24 and 32 bits. Image Resolution - 320x240, 640x480 and 720x576 etc. PSD, AI, JPG, BMP, GIF, PNG, TGA, TIF and EPS etc. Stereo Mono 5.1 Audio: Sample Rate , 22050, 32000, 44100, 48000, Hz. Sample Type - 8, 16, 24, 32 bits. Channels - Mono, Stereo and 5.1 Surround Sound. Audio CD Hz, 16bits and Stereo. AIF, MP3, Wav, RA, MOV, ASF and AVI etc. Video: Color Depth - 8, 16, 24 and 32 bits. Frame Size - 320x240, 640x480 and 720x576 etc. Frame Rate - 5, 8, 12, 15, 24, 25, and 30 fps etc. Pixel Aspect Ratio - Square Pixels (1.0), DV NTSC (0.9), DV PAL (1.067), Widescreen16:9 (1.422) etc. AVI, MOV, WMV, MPEG, etc

18 Uncompress Video Size 720 X 480 x 3 = Frame Storage HR VR RGB 1 Frame Size Video Compression: The goal of data compression is to represent the same content (Quality) using the less data (Storage). Using the Codec (Compressor/Decompressor) to manage the compression. 1 Frame = 1 MB 1 Second = 30 MB 1 Minute = 1.5 GB Spatial Compression Whole Frame Repeating Pixels Non-Repeating Pixels Spatial compression uses a method to delete information that is common to the entire frame by looking for pattern and repetition among of pixels. It looks for redundant information, but instead of specifying each pixel in an area, it defines that area using coordinates. Whole Sequence Key Frame Temporal Compression Delta Frames This method of compression looks for information that is not necessary for continuity to the human eye. It looks at the video information on a frame-by-frame basis for changes between frames. The compression algorithm compares the first frame (Key Frame) with the next (Delta Frame) to find anything that changes. After the key frame, it only keeps the information that does change, thus deleting a large portion of the file. It does this for each frame until it reaches the end of the file.

19 THE CREATIVE PROCESS DVD Video Training in Adobe Premiere Pro

20 THE CREATIVE PROCESS An Overview of Movie-Making: A Movie-Making Process Better making a movie includes Pre-Production, Production and Post Production. Pre-Production is the planning stage. Typically, it includes steps to take before beginning production (Shooting Film or Video). But this is a flexible process and the non-linear editing methods made possible by the advent of digital video make it even more so. When beginning the project, it may have already shot some or all of the video as need. Production, Capturing live or animated action and sound on film, videotape, or DV - Shooting or Creating raw footage. Post-Production, edit and assemble the clips and, perhaps, add visual effects, graphics, titles, and a sound track. An Overview of Movie-Making Pre-Production Production Post Production Plan the Project Create / Gather Raw Material Capture / Import Assemble / Edit Create / Composite Output and Distribute Outline Script Storyboard Budget/Finance Locations Shoot Video. Create Text, Graphics and Audio. Import Graphic, Audio and Video. Digitize Analog/Digital Audio and Video. Using Non- Linear Editing system to Assemble and Edit the Video. Create Motion Graphics and Visual Effects in a Composite system. Render and Export the Video to the Web, CD- Rom, DVD, Video Tape and Film.

21 THE CREATIVE PROCESS Linear and Non-Linear Editing: Linear Editing is the standard process used successfully for many years where you copy parts of your video source material from your camcorder to a VCR to build up your final program. Non-Linear Editing (NLE) makes editing and assembling your production as easy and as flexible as word processing. Random-access editing of video and audio on a computer, allowing for edits to be processed and re-processed at any point in the timeline, at any time. Traditional videotape editors are linear because they require editing video sequentially, from beginning to end. Once your raw materials are in your computer, you can edit, alter, adjust, and reconfigure them - over and over again - with a few mouse clicks. Online and Offline Editing: Online Editing: Online editing is the practice of doing all editing (Including the Rough Cut) on the same clips that will be used to produce the final cut. Previously, online editing had to be done on costly, high-end workstations designed to meet the quality and data-processing requirements of broadcast video. When you work with DV source material, all editing is done online. DV compression makes standard DV manageable on many desktop systems. For online editing using analog source material, you capture clips once at the highest level of quality your computer and peripherals can handle. Offline Editing: In offline editing, you edit a rough cut of your video using low-quality clips, and then produce the final cut using high-quality clips.

22 THE DISTRIBUTING OF THE PRODUCTION DVD Video Training in Adobe Premiere Pro

23 THE DISTRIBUTING OF THE PRODUCTION Record and Export the Timeline: Web The program edited in the Timeline does not actually contain the material from which it was pieced together - rather, it references the source files. Before export, make sure that the timeline is ready to output at the quality require. For example, replace any offline files with high-resolution files suitable for final export. To get the edited program out of the computer in one piece, it can: Record the timeline to physical media including videotape or motion picture film, if it has the proper hardware for video or film transfer, or has access to a service provider that offers the appropriate equipment and services. Export a video file for viewing from a hard disk, removable cartridge, CD-ROM, DVD, or the Web. It can also output stills or sequences of stills, portions of the timeline as clips, and/or an EDL (Edit Decision List). CD-ROM, DVD Video Tape Timeline

24 THE CONFIGURATION OF THE SYSTEM DVD Video Training in Adobe Premiere Pro

25 THE CONFIGURATION OF THE SYSTEM Amateur System Software and Hardware: Non-Linear Video Editing requites both Software Applications and Hardware Systems to achieve the goal. Software Applications: Adobe Premiere Pro, Pinnacle Liquid Edition, Avid Xpress Pro and Apple Final Cut Pro etc. Hardware Systems: Windows, Macintosh, Linux, IRIX etc. DV Camcorder Personal Computer With an IEEE 1394 Card 1024x bit Video Adapter at least. NOTE: It s important to check the Software Applications and their Hardware Requirements before invest on an Editing System. Prosumer System Professional System TV Monitor DV Camcorder Extend Storage Personal Computer With a Real-Time DV Card 1280x bit Video Adapter at least. TV Monitor DV Camcorder DV Deck Disk Array PC With a Real-Time Analog/DV Editing System 1600x bit Dual-Head Video Adapter.

26 Visual Contents Studio For a latest version of this document, Please go to DVD Video Training in Adobe Premiere Pro