In motion pictures, television, and in computer video displays, the frame rate is the number of frames or images that are projected or displayed per second. Frame rates are used in synchronizing audio and pictures, whether film, television, or video. In motion pictures and television, the frame rates are standardized by the Society of Motion Picture and Television Editors (SMPTE). SMPTE Time Code frame rates of 24, 25 and 30 frames per second are common, each having uses in different portions of the industry. The professional frame rate for motion pictures is 24 frames per second and, for television, 30 frames per second (in the U.S.).

In computer video streams, the frame rate describes playback rates for AVI and QuickTime movies. The video playback rate for an AVI or QuickTime movie directly relates to the perceived smoothness of its playback. The higher the number of frames playing per second, the smoother the video playback appears to the user. Lower rates result in a choppy playback. (As a reference point, film uses 24 frames per second to allow the viewer to perceive smooth playback.) Several factors affect the actual frame rate you get on your computer. For example, your PC processor or graphics hardware may only be capable of playing 10-15 frames per second without acceleration.

In developing motion pictures, television, and video, frame rate information is used as a reference for audio signals. The recorded signal includes information about location in time using a 24-hour clock, and individual frame numbers. This signal is used to synchronize multiple audio and video machines during the recording and editing process. Using a master synchronizing device, the operator can issue location commands from a central machine and have all slaved machine follow the master.

National Television System Committee

The name for the method used to transmit television signals in North America. Actually, the name of the group that sets the broadcast television standards in North America. Originally formed to standardize the method for color television broadcasting. The method chosen (augmenting the existing monochrome composite video signal) was standardized in 1953 and is still the standard for North America and Japan. The frame rate is 29.97 frames per second (0.1% slower than the original 30 frames per second, to avoid interference with the color subcarrier part of the NTSC television signal). In contrast, computer video usually runs at 30 frames per second, since it does not use NTSC. Each frame is made up of two fields, with the second field writing between the lines of the first, to provide more displayed lines per frame (the persistence of the CRT phosphor is long enough that the first field remains displayed while the second is being written). Each frame is made up of 481 horizontal lines (240.5 lines per field) that are visible (sometimes called "active") plus another 44 lines (22 per field) that are blanked (the electron beam is turned off ), since they occur while the scanning beam returns to the upper-left corner of the screen. This makes a total of 525 lines per frame. Such interlaced scanning was necessary to fit the screen resolution desired into the video bandwidth available. Newer technologies (such as computer monitors and HDTV) usually use noninterlaced (also called progressive) scanning. The term "NTSC" is also used to refer to the standard video signal that is used (for example) between a video cassette recorder (a standard home VCR) and television (it uses what is often called an RCA connector). When broadcasted, an NTSC signal requires a 6-MHz bandwidth. That is, channel 2 is 54 to 60 MHz, channel 3 is 60 MHz to 66 MHz, and so on.

To reduce interference, adjacent television channels (for example, channels 3 and 4) are not assigned in the same coverage area, and the transmitting antennas of transmitters that are assigned to the same frequency must be at least 155 miles apart. For each 6-MHz channel: The main (sometimes called video) carrier frequency is 1.25 MHz above the base frequency (of 54 MHz for channel 2, for example--so the video carrier is at 55.25 MHz). This carrier is amplitude modulated (AM) by the composite video signal (which has all of the picture and synchronization information). The (left+right) sound information is sent by frequency modulating (FM) a sound subcarrier that is 4.5 MHz above the video carrier frequency (so the sound for channel 6 is at 87.75 MHz--which explains why you can usually hear broadcast TV audio on a standard FM radio, since FM starts just above this, at 88 MHz). For stereo signals, an FM left-right audio signal is also sent, at a pilot frequency above the sound subcarrier. Standard television has a 4:3 (horizontal:vertical) aspect ratio. Regular monochrome (black-and-white) television broadcasts began in 1936 in Britain and in 1939 in the U.S. NTSC video can produce the changes per horizontal line listed in the following table. (These limitations are due to the modulation methods and frequencies chosen.)

PAL and SECAM are similar-technology systems that are used outside of North America. A higher-quality (than NTSC) standard is called S-Video and is supported by some VCRs and televisions.

Séquentiel Couleur Avec Mémoire

The analog color television broadcasting standard that is used in Eastern Europe and Russia. There are many different implementations, with names like SECAM-B (which requires 7 MHz per channel) and SECAM-L (which requires 8 MHz per channel--and, one hopes, can produce a better picture).

Phase-Alternation Line

The broadcast color television standard used in Western Europe (including the U.K.) and Australia. Compared to North America's NTSC, PAL:

1. Is not as well standardized (many countries use slightly different implementations)
2. Usually has better resolution (625 lines, compared to NTSC's 525 lines)
3. Usually has a slower frame rate (25 rather than 29.97 frames per second--therefore often showing noticeable flicker)
4. Uses a similar method of adding the color information (using a sub-carrier)--though the color (often called the hue or tint) is automatically calibrated and so does not need adjustment, as North American televisions do
5. Has the same 4:3 aspect ratio

Many countries have slightly different implementations of PAL, with names such as PAL-M (which is used in Brazil and is similar to NTSC in that it requires 6 MHz for each channel, has 626 lines per frame, and uses 60 Hz scanning) or PAL-I1 (which requires 8 MHz per channel, has 625 lines per frame, and uses 50 Hz scanning--and can provide a better picture because of it).

High-Definition Television

Motion Picture Experts Group

A committee of the ISO that has produced a standard for lossy data compression and storage of full-motion video. Interpolating between frames is used to provide better compression than the JPEG method, but this prevents the MPEG method from being used in frame-by-frame applications, such as editing and switching.

MPEG-1 is intended for computers, games, and set-top boxes (that is, a box that sits on top of your television, perhaps bringing video from the information highway--whatever that turns out to be). The video has a resolution of 352 x 240 pixels (horizontal by vertical) at 30 frames per second. Using specialized hardware (an MPEG decompression IC), it can provide near VHS-quality desktop video (that is, it is almost as good as playing a rented videotape on a home VCR) at a data rate of 150 kbytes/s (which is the data rate from a standard single-speed CD-ROM player).

MPEG-2 is intended for use with broadcast-quality (that is, really expensive and very high-quality) applications and defines a transport (protocol) that supports functions such as adding closed-captioning and different language channels.

• I (Intra) key frames are compressed by using JPEG and used to support quickly scanning through a file and as reference points for B and P frames.
• P (Predicted) frames are generated by comparing redundancies in images that are several frames apart (that is, looking for blocks of video data that are the same as portions of previous I frames).
• B (Bidirectional Interpolated) frames are generated by looking for redundancies in the immediately preceding and also succeeding P or I frames.

MPEG-1 competes with AVI video. For normal home use, MPEG-2 encodes at 3 Mbits/s, so an average 2-hour movie would require 2.7 Gbytes of storage.

Dr. Kilgore says:

Technically its called 2:3 pulldown, but everyone says it backwards...

An NTSC video image consists of 525 horizontal lines of information. The electron gun scans top to bottom, left to right, odd numbered lines first, then the even numbered lines. Each full scan of even numbered lines, or odd numbered lines constitutes a "field". Each field scan takes 1/60th of a second, therefore a whole frame is scanned each 1/30th of a second. (literally 29.97 frames per second)

Film is generally shot and projected at 24 frames per second (fps), so when film frames are converted to NTSC video, the rate must be modified to play at 29.97 fps. During the telecine process, twelve (12) fields are added to each 24 frames of film (12 fields = 6 frames) so the same images that made up 24 frames of film then comprise 30 frames of video. Video plays at a speed of 29.97 fps so the film actually runs at 23.976 fps when transferred to video.

That means that the first frame of film is represented by 2 fields of video; the second frame of film is represented by 3 fields of video (1.5 frames); the third frame of film is again represented by two ields and the fourth frame of film is represented by 3 fields, and so on. In the end, what was running at 23.976 fps is running at 29.97 fps.

Captain Bob says:

3:2 Pulldown - Conversion of film frame rate material (24 fps) to NTSC video (29.97 fps) which results in the addition of approximately 6 frames per second. Pulldown frames are created by blending frames from the original source in a specific pattern, and is very undesirable in compressed movies. Pulldown is introduced with a system called a "Telecine", and may be removed with Media Cleaner's "Intelecine" feature, or TMPGEnc's reverse telecine feature.

FILM is shot at 24 frames per second (fps), but NTSC television (the standard television format in North America -represented by VIDEO above) runs at 30 fps. The necessary conversion from 24 distinct FILM frames into 30 new VIDEO frames takes place using a process called "3:2 Pulldown". In the VIDEO example above you will see the following pattern: 3 "As", 2 "Bs", 3 "Cs", 2 "Ds" – hence 3:2 pulldown. Without this conversion FILM would run at 125% its original speed when displayed as VIDEO on your television: 1 minute of film would display in 48 seconds.

• The first frame of video contains two fields of the 1st (A) frame of film.
• The second frame of video contains two fields of the 2nd (B) frame of film.
• The third frame of video contains one field of the 2nd (B) and 3rd (C) frames of film.
• The fourth frame of video contains one field of the 3rd (C) and 4th (D) frames of film.
• The fifth frame of video contains two fields of the 4th (D) frame of film.

If we look at the illustration below its easier to see whats happening

Dr. Kilgore says:

Because this process involves duplication of frames and fields to stretch 24 fps to 30 fps, artifacts can occur during high-motion scenes. Jerky motion of objects, called "judder," may also be visible during lateral pans. These artifacts affect all source material originally shot on film and subsequently transferred to video, including DVDs, VHS tapes, and many television programs.

How does 3:2 Pulldown work?

Each frame of NTSC VIDEO contains 2 "fields", which equals 60 fields in a second (remember- VIDEO runs at 30 fps). Now it's a matter of simple math: 24 and 60 have a common denominator of 12. Thus: 2x12=24 and 3x12=36. When we mix "2 pattern's and "3 patterns" of fields (24+36) we get 60 fields in a second. Basically, 1 frame of FILM is placed on 3 fields of VIDEO, the the next frame of FILM is placed on 2 fields of VIDEO and so on. The result is that every 4 frames of FILM will land on every 5 frames of VIDEO: 24 divided by 6 equals 4 frames of FILM, and 30 divided by 6 equals 5 frames of VIDEO.

There is also an excellent article devoted to 3:2 in our Articles section

or I love Panavision

See Our Page devoted to Anamorphic Widescreen... Here

I love the really Widescreen. I prefer 2.35:1 aspect ratio. A.K.A. Panavision. most of the time though anamorphic DVD is in 1.85:1 not true panavision. An excellent resource for widescreen is The Ultimate Guide to Anamorphic Widescreen DVD for Dummmies

VCD

VCD (also called video CD, video compact disc or "disc") is a compact disk format based on CD-ROM XA that is specifically designed to hold MPEG-1 video data and to include interactive capabilities. VCD has a resolution similar to that of VHS, which is far short of the resolution of DVD. Each VCD disk holds 72-74 minutes of video and has a data transfer rate of 1.44 Mbps. VCDs can be played on a VCD player connected to a television set (in the same way that video cassettes can on a VCR) or computer, on a CD-i player, on some CD-ROM drives, and some DVD players. VCD was introduced in 1993 by JVC, Philips, SONY and Matsushita and is described in detail in the White Book specifications.

Video data is demanding in terms of storage capacity; it requires approximately 5 MB of storage per second of video, which would translate to about two minutes of video on a 680 MB CD. In order to store video information on a CD in a practical fashion, the data must be compressed for storage and then decompressed for replay in real time. MPEG-1 compresses data at ratios of up to 200:1. MPEG is an international standard, and can be used by any manufacturer to create hardware for use with MPEG video. MPEG video can also be recorded on any CD. VCD formatting removes unnecessary information from MPEG-1 data, and adds specialized video authoring capabilities through inclusion of a CD-i (CD- Interactive) runtime application.

VCD variations include: VCD 2.0, which was introduced in 1995 and adds hi-resolution stills, fast-forward, and rewind functions to the original specifications; VCD-ROM, which was introduced in 1997 and enables the creation of hybrid VCD/CD-ROM disck; VCD-Internet, which was introduced in 1997 and is a standardized means of linking video and Internet data; and SuperVCD, which uses either high bit rate MPEG-1 or variable bit rate MPEG-2 for the use of CD-R drives instead of DVD drives.

VCD is more common in Asia than it is in North America, where the VCR had already cornered the home video market by the time that VCD was introduced. Because of the ease with which VCDs can be pirated, they are creating the same kind of problem for the movie industry that MP3 caused for the music industry. Thieves may record movies from a movie screen with a camcorder, or may copy them from laserdiscs or DVDs. With the advent of recordable CDs (such as the CD-R and CD-RW), it became possible for the home user to create VCDs on some CD recorders.

CD-ROM XA

CD-ROM XA (Compact Disc - read-only-memory, extended architecture) is a modification of CD-ROM that defines two new types of sectors that enable it to read and display data, graphics, video, and audio at the same time. CD-ROM XA was developed jointly by Sony, Philips, and Microsoft, and its specifications were published in an extension to the Yellow Book.

CD-ROM XA (for eXtended Architecture) discs contain Mode 2 sectors (areas left free for extra data by the omission of error detection and correction code) and were designed to allow audio and other data to be interleaved and read simultaneously. Formerly, images had to be loaded before the audio tracks could be played. The CD-ROM XA specifications include 256 color modes, which are compatible with PC formats and CD-i, and Adaptive Differential Pulse Code Modulation (ADPCM) audio, which is also defined for CD-I. Photo CD, Video CD and CD-EXTRA have all subsequently been based on CD-ROM XA, although it has not survived as a separate technology.

DVD

digital versatile disc

DVD (digital versatile disc) is an optical disc technology that is expected to rapidly replace the CD-ROM disc (as well as the audio compact disc) over the next few years. The digital versatile disc (DVD) holds 4.7 gigabyte of information on one of its two sides, or enough for a 133-minute movie. With two layers on each of its two sides, it will hold up to 17 gigabytes of video, audio, or other information. (Compare this to the current CD-ROM disc of the same physical size, holding 600 megabyte. The DVD can hold more than 28 times as much information!) DVD-Video is the usual name for the DVD format designed for full-length movies and is a box that will work with your television set. DVD-ROM is the name of the player that will (sooner or later) replace your computer's CD-ROM. It will play regular CD-ROM discs as well as DVD-ROM discs. DVD-RAM is the writeable version. DVD-Audio is a player designed to replace your compact disc player.

DVD uses the MPEG-2 file and compression standard. MPEG-2 images have four times the resolution of MPEG-1 images and can be delivered at 60 interlaced fields per second where two fields constitute one image frame. (MPEG-1 can deliver 30 noninterlaced frames per second.) Audio quality on DVD is comparable to that of current audio compact discs.