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| Video Formates | - AVI
Audio Video Interleaved - A multimedia file format for storing sound and moving
pictures in RIFF format developed by Microsoft. An AVI file can use different
codecs and formats so there is no set format for an AVI file unlike for example
standard VCD video which sets a standard for resolution, bitrates, and codecs
used. - MPEG-1
An ISO/IEC (International Organization for Standardization/ International Electrotechnical
Commission) standard for medium quality and medium bitrate video and audio compression.
It allows video to be compressed by the ratios in the range of 50:1 to 100:1,
depending on image sequence type and desired quality. The encoded data rate is
targeted at 1.5Mb/s - this was a reasonable transfer rate of a double-speed CD-ROM
player (including audio and video). VHS-quality playback is expected from this
level of compression. The Motion Picture Expert Group (MPEG) also established
the MPEG-2 standard for high-quality video playback at a higher data rates. MPEG-1
is used in encoding video for VCD.
- MPEG-2
An encoding standard designed as an extension of the MPEG-1 international standard
for digital compression of audio and video signals. MPEG-1 was designed to code
progressively scanned video at bit rates up to about 1.5 Mbit/s for applications
such as CD-i. MPEG-2 is directed at broadcast formats at higher data rates; it
provides increased support for efficiently coding interlaced video, supports a
wide range of bit rates and provides for multichannel surround sound coding such
as PCM, Dolby Digital, DTS and MPEG audio.
- MPEG / VCD
/ SVCD/ DVD
MPEG is the dominant file format used to create VCD,
SVCD and DVD. This high quality compressed format can be used across all platforms.
VCD, SVCD and DVDs accept MPEG files that conform to their respective standards.
MPEG files differ in many parameters that characterizes the MPEG format.
The table below lists down the format in which MPEG files are made by Video Workshop
depending on the type of video disc.
| Video
Disc | MPEG
Format (Standard) | | Disc
Format | Picture
Standard | Disc
Type | MPEG
Type | Dimension
(pixels) | Frame
Rate (FPS) | Video
Bitrate (Kbps) | Audio
Bitrate (Kbps) | | VCD | NTSC | CD | MPEG
1 | 352
x 240 | 29.97 | 1152 | 224 |
| VCD | PAL | CD | MPEG
1 | 352
x 288 | 25 | 1152 | 224 |
| SVCD | NTSC | CD | MPEG
2 | 480
x 480 | 29.97 | 2500 | 192 |
| SVCD | PAL | CD | MPEG
2 | 480
x 576 | 25 | 2500 | 192 |
| DVD | NTSC | DVD | MPEG
2 | 720
x 480 | 29.97 | 6000 | 224 |
| DVD | PAL | DVD | MPEG
2 | 720
x 576 | 25 | 6000 | 224 |
- NTSC
Abbreviation of National Television Standards Committee. The
NTSC is responsible for setting television and video standards in the United States
(in Europe and other parts of the world, the dominant television standards are
PAL and SECAM). The NTSC standard for television defines a composite video signal
with a refresh rate of 60 fields (half-frames interlaced) per second. Each frame
contains 525 lines and can contain 16 million different colors. The resolution
of an NTSC VCD is 352x240 pixels, an NTSC SVCD is 480x480, and an NTSC full D1
DVD is 704 or 720 x 480. - PAL
Short for Phase Alternating Line, the dominant television standard in
Europe. The United States uses a different standard, NTSC. PAL delivers 625 lines
at 50 fields (half-frames interlaced) per second. The resolution of a PAL VCD
is 352x288 pixels, a PAL SVCD is 480x576, and a PAL full D1 DVD is 704 or 720
x 576.
- ASF
Advanced Streaming Format (ASF): This file format stores audio and video information,
and it is specially designed to run on networks like the Internet. This file format
is a highly flexible and compressed format that contains streaming audio, video,
slide shows, and synchronized events. When you use .asf files, content is delivered
to you as a continuous flow of data. You no longer have to wait for your audio
and video files to fully download before you start to view them. When an AVI file
is compressed and converted to an .asf file, the file begins playing after only
a few seconds. The file can be unlimited in length and can run over Internet bandwidths.
- MOV,QT
(Quick Time)
A digital video Format standard developed by Apple Computer
for Macintosh (Mac OS) and Windows operating systems.
- RM
Real
Media streaming format for audio/video data.
- MP4
A container format allows you to combine different multimedia
streams (most of the time audio and video) into one single file.
Multimedia
containers are for example the well known AVI (.avi), MPEG (.mpg, .mpeg), Matroska
(.mkv, .mka), OGM (.ogm), Quicktime (.mov) or Realmedia (.rm, .rmvb)
MP4 is the global file extension for the official container format defined in
the MPEG-4 standard (ISO 14496-14)
MP4 is streamable and supports all kinds
of multimedia content (multiple audio-, video-, subtitlestreams, pictures, variable-framerates,
-bitrates, -samplerates...) and advanced content (officially called "Rich
Media" or "BIFS") like 2D and 3D animated graphics, user interactivity,
DVD-like menus... - next to nothing handled by the often used AVI
- iPod MP4
A file format developed for iPod video. - PSP
MP4 A file format developed for PlayStation Portable (PSP).
- 3GP
The mpeg4 based video format used in mobile terminals, like cell
phones.
| Cellular
Phone Model | Video
Output | Audio
Output | | Sony
Ericsson W800i | Bit
rate: 500kbps
Format: h263
Size: 176x144
pixel
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| | Sony
Ericsson K750i | Bit
rate: 104kbps
Format: mpeg4
Size: 176x144
pixel
Frame rate: 25.00fps | Format:
mpeg4aac
Sample rate: 22050Hz
Channels:
Mono | Nokia
6230 | Bit
rate: 118kbps
Format: mpeg4
Size: 128x96
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Nokia
6620 | Bit
rate: 79kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Nokia
6630 | Bit
rate: 138kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Motorola
V710 | Bit
rate: 78kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Motorola
V635 | Bit
rate: 216kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Motorola
V547 | Bit
rate: 122kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Samsung
D. 500 | Bit
rate: 73kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| Sanyo
5600 | Bit
rate: 96kbps
Format: h263
Size: 176x144
Frame rate: 25.00fps | Format:
amr_nb
Sample rate: 8000Hz
Channels: Mono
| - Flash
Video (FLV)
SWF is not the only Flash format. FLV
files (Flash Video Files) are a binary file format that delivers "bitmapped"
video, limited to one video and one audio stream per file, over the Internet to
the Macromedia Flash Player version 7. FLV content may also be associated with
SWF files by ActionScript external references. FLV format can also imported
into Macromedia Flash Authoring tool.
Unlike SWF format, FLV do not have
maximum of 16000 frames limitation and ideally for large
video file size. - Frame
Television:
A set of scanlines in video to make a complete
picture. If the video is interlaced the frame consists of both of the interlaced
fields (half frames). If the video is progressive the the frame is made up of
one continuous scan from top to bottom. The number of scanlines vary in a frame
depending on the TV system used. PAL50 uses 625 scan lines, NTSC60 (US) 525.
Video Encoding:
A frame is one picture but depending on the encoding
scheme it may not be a complete picture (I-Frame) but dependent on frames before
or after the current frame (P-Frame, B-Frame).
- MP3
MP3 is an acronym for MPEG-1 (or MPEG-2) Layer 3 audio encoding (it is not an
acronym for MPEG3). MP3 is a popular compression format used for audio files on
computers and portable devices.
The compression in MP3 works on the
basis of a "psychoacoustic model" which means that parts of the audio
that human ears cannot detect are discarded by the encoder. Although this is a
LOSSY process, it can yield very high quality audio files are relatively high
compression rates.
A typical MP3 file encoded at 128 kbit/s (12:1 compression)
is near CD quality. - Wave
Wave is the standard form for uncompressed audio on a PC. Since a wave
file is uncompressed data - as close a copy to the original analog data as possible
- it is therefore much larger than the same file would be in a compressed format
such as mp3 or RealAudio. Audio CDs store their audio in, essentially, the wave
format. Your audio will need to be in this format in order to be edited using
a wave editor, or burned to an audio CD that will play in your home stereo.
- Sample Rate
The sample rate of an audio recording partially determines the overall
sound quality. In the recording process, audio samples are saved to memory or
disk; the rate each sample of audio input is recorded per second is the sample
rate. The sample rate is measured in Hertz (Hz - cycles per second) and Kilohertz
(kHz - thousand cycles per second). CD quality audio has a sample rate of 44100Hz,
16-bit (resolution) and stereo (channels). The most common sample rates are 11,
22 and 44kHz, with most recording software supporting sample rates from 6kHz up
to 192kHz. Like early footage filmed at a low frame rate looks flickered and robotic,
the quality of an audio recording decreases as the sample rate is lowered. For
audio recordings destined to be encoded to MP3, 22kHz is considered acceptable. - Bit
Rate
Bit rate is the amount of information (bits) transferred
in a second ('bps' is the abbreviation of bits-per-second). Bitrate or
Bit Rate is the average number of bits that one second of video or audio data
will consume. Higher bitrate means bigger file size and generally better video
or audio quality while lower bitrate means lower file size but worse video or
audio quality. Some bitrate examples in common video and audio files:
MP3
about 128 kbps (kilobits per second)
VCD about 1374 kbps
DVD about 4500
kbps
DV about 25 Mbps (megabits per second).
- bps
Bits per second. A unit of data rate
- fps
Frames per second. A measure of the rate at which pictures are shown for a motion
video image. In NTSC and PAL video, each frame is made up of two interlaced fields.
- Codec
An acronym for "compression/decompression", a codec is an algorithm
or specialized computer program that encodes or reduces the number of bytes consumed
by large files and programs. Files encoded with a specific codec require the same
codec for decoding. Some codecs you may encounter in computer video production
are Divx, MPEG-1, MPEG-2, Xivd, DV type 1 and type 2 for video and MP3 for audio.
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