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.
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 donot 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.
