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Supported Video Formats
| Format |
Description |
| AVI
(DivX, XviD, MPEG-4, Uncompressed, Cinepak) |
| |
AVI stands for Audio Video Interleave.
It is a special case of the RIFF (Resource Interchange
File Format). AVI is defined by Microsoft. AVI
is the most common format for audio/video data
on the PC. AVI is an example of a de facto (by
fact) standard.
AVI Files are a special case of RIFF files.
RIFF is the Resource Interchange File Format.
This is a general purpose format for exchanging
multimedia data types that was defined by Microsoft
and IBM during their long forgotten alliance.
Please note: If there are
not DivX or XviD codec installed in your computer,
you need to download and install the DivX or
XviD codec so that you can operate DviX or XviD
video files.
DviX: http://www.divx.com/divx/
(free version is enough for palying and converting
DivX video files)
XviD: http://www.xvidmovies.com/codec/
For the details, please see FAQ |
|
| MPEG
(MPEG-1, MPEG-2 Video) |
| |
MPEG is both a file format and a
codec for digital video. There are actually three
forms of MPEG: MPEG video, for picture only; MPEG
audio, which is discussed in the previous section;
and MPEG systems, which includes both audio and
video tracks.
MPEG files provide excellent picture quality but
can be very slow to decompress. For this reason,
many MPEG decoding systems are hardware-assisted,
meaning that you need a board to play MPEG files
reliably without dropping a lot of frames. Although
software decoders definitely exist (and there
are some very good ones out there), they tend
to require a lot of processor power on your system
and also usually support MPEG video only (they
have no soundtrack).
A third drawback of MPEG video as a standard for
the Web is that MPEG movies are very expensive
to encode. You need a hardware encoder to do so,
and the price ranges for encoders are in the thousands
of dollars. As MPEG becomes more popular, those
prices are likely to drop. But for now, unless
you already have access to the encoding equipment
or you're really serious about your digital video,
a software-based format is probably the better
way to go. |
|
| WMV |
| |
Windows Media Video.
Formerly known as .ASF file format from Microsoft.
A .WMV file includes a video stream (compressed
using MS MPEG4 or WMV1 codec) combined with
WMA encoded audio stream. The file format is
proprietary and backward incompatible. Currently,
dedicated to slow dialup connections, this media
format does not allow even sub-VHS video quality
due to blurred picture. WMA audio quality, compared
to MPEG Layer3 of the same bitrate, isn't better
either.
You may wish to use Windows Media format to
create smallest files that are suitable to send
by e-mail, however you must keep in mind that
.WMV file works like "one way ticket"
- once created, it can't be edited anymore,
without horrific quality loss. As opposite,
AVI files compressed with MPEG4 video codec
are still editable and often it is possible
to retain source video quality.
If you are having problems creating or playing
Windows Media files, download the latest codecs.
These may be found at http://www.microsoft.com/windows/windowsmedia/format/codecdownload.asp.
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| RM |
| |
Real Networks Video (convert to
only)
It is a streaming media format known as RealMedia
with the file extension .rm using RealAudio audio
compression and RealVideo video compression (RealVideo,
also known as ClearVideo, is Iterated Systems
fractal video compression). |
|
Quick
Time |
| |
Apple video format for the Macintosh
(convert from only)
Although QuickTime was developed by Apple for
the Macintosh, QuickTime files are the closest
thing the Web has to a standard cross-platform
movie format (with MPEG a close second). The
Apple system software includes QuickTime and
a simple player (called MoviePlayer or SimplePlayer).
For PCs, QuickTime files can be played through
the QuickTime for Windows (QTfW) package, and
the freely available Xanim program will play
them under the X Window System and UNIX. QuickTime
movies have the extension .qt or .mov.
QuickTime supports many different codecs, particularly
CinePak and Indeo, both of which can be used
cross-platform. See the "Codec Formats"
section later in this chapter for more information
on these formats. |
|
Supported Audio Formats
| Format |
Description |
| PCM |
| |
Standard Windows WAV format for
non-compressed audio files. Pulse Code Modulation
(PCM) is the standard method of digitally encoding
audio. It is the basic uncompressed data format
used in file types such as Windows .wav. |
|
| ADPCM |
| |
Compressed WAV format. ADPCM (Adaptive
Differential Pulse Code Modulation) is an audio
compression scheme which compresses from 16-bit
to 4-bit for a 4:1 compression ratio. |
|
| A-LAW |
| |
Compressed WAV format. A-Law (or
CCITT standard G.711) is an audio compression
scheme common in telephony applications. It is
a slight variation of the u-Law compression format,
and is found in European systems. This encoding
format compresses original 16-bit audio down to
8 bits (for a 2:1 compression ratio) with a dynamic
range of about 13-bits. Thus, a-law encoded waveforms
have a higher s/n ratio than 8-bit PCM, but at
the price of a bit more distortion than the original
16-bit audio. The quality is higher than you would
get with 4-bit ADPCM formats. Encoding and decoding
is rather fast and generally, widely supported.
|
|
| U-LAW |
| |
Compressed WAV format. u-Law (or
CCITT standard G.711) is an audio compression
scheme and international standard in telephony
applications. u-Law is very similar to A-Law,
a variation of u-Law found in European systems.
This encoding format compresses original 16-bit
audio down to 8 bits (for a 2:1 compression ratio)
with a dynamic range of about 13-bits. Thus, u-Law
encoded waveforms have a higher s/n ratio than
8-bit PCM, but at the price of a bit more distortion
than the original 16-bit audio. The quality is
higher than you would get with 4-bit ADPCM formats.
Encoding and decoding is rather fast and generally,
widely supported. |
|
| CCIT
U-LAM |
|
| DSP |
| |
Compressed WAV format. DSP Group
True Speech (TM) format. |
|
| GSM |
| |
Compressed WAV format. Good for
keeping of human speech. |
|
| MP3 |
| |
MPEG Layer-3 format. Very popular
format for keeping of music. |
|
MP2 |
|
| Ogg
Vorbis |
| |
Ogg Vorbis format. Ogg Vorbis is
an audio compression format. It is roughly comparable
to other formats used to store and play digital
music, such as MP3, VQF, AAC, and other digital
audio formats. It is different from these other
formats because it is completely free, open, and
unpatented. |
|
| WMA |
| |
Windows Media Audio format. A special
type of advanced streaming format file for use
with audio content encoded with the Windows Media
Audio codec. The .wma extension indicates a file
format and how the content is encoded. |
|
AVI |
| |
Audio stream format (Convert
From Only) |
|
AIF,
AIFF, AIFC |
| |
Apple audio file format
(Convert From Only)
|
|
AU,
SND |
| |
Unix audio file format
(Convert From Only)
|
|
G.721 |
| |
Used for computer telephony. 32
kbit/s adaptive differential pulse code modulation
(ADPCM).
Good for keeping of human speech. |
|
G.723 |
| |
Used for computer telephony. Extensions
of Recommendation G.721 adaptive differential
pulse code modulation to 24 and 40 kbit/s for
digital circuit multiplication equipment application.
Good for keeping of human speech. |
|
| G.726 |
| |
Used for computer telephony. Good
for keeping of human speech. |
|
| VOX |
| |
Dialogic ADPCM format. The Dialogic
ADPCM format is commonly found in telephony applications,
and has been optimized for low sample rate voice.
It will only save mono 16-bit audio, and like
other ADPCM formats, it compresses to 4-bits/sample
(for a 4:1 ratio). This format has no header,
so any file format with the extension .VOX will
be assumed to be in this format. |
|
| RAW |
| |
Raw format of audio files. Doesn't
contain header of an audio file. |
|
MPC |
|
Supported Image Formats
| Format |
Description |
| JPEG |
| |
Joint Photographic Experts Group
(JPEG) format is commonly used to display photographs
and other continuous-tone images in hypertext
markup language (HTML) documents over the World
Wide Web and other online services. JPEG format
supports CMYK, RGB, and Grayscale color modes,
and does not support alpha channels. Unlike GIF
format, JPEG retains all color information in
an RGB image but compresses file size by selectively
discarding data.
A JPEG image is automatically decompressed when
opened. A higher level of compression results
in lower image quality, and a lower level of compression
results in better image quality. In most cases,
the Maximum quality option produces a result indistinguishable
from the original. |
|
| GIF |
| |
Graphics Interchange Format (GIF)
is the file format commonly used to display indexed-color
graphics and images in hypertext markup language
(HTML) documents over the World Wide Web and other
online services. GIF is an LZW-compressed format
designed to minimize file size and electronic
transfer time. GIF format preserves transparency
in indexed-color images; however, it does not
support alpha channels. |
|
| BMP |
| |
BMP is a standard Windows image
format on DOS and Windows-compatible computers.
BMP format supports RGB, Indexed Color, Grayscale,
and Bitmap color modes. You can specify either
Windows or OS/2® format and a bit depth for
the image. For 4-bit and 8-bit images using Windows
format, you can also specify RLE compression.
BMP images are normally written bottom to top;
however, you can select the Flip Row Order option
to write them from top to bottom. You can also
select an alternate encoding method by clicking
Advanced Modes. (Flip Row Order and Advanced Modes
are most relevant to game programmers and others
using DirectX.) |
|
| PNG |
| |
Developed as a patent-free alternative
to GIF, Portable Network Graphics (PNG) format
is used for lossless compression and for display
of images on the World Wide Web. Unlike GIF, PNG
supports 24-bit images and produces background
transparency without jagged edges; however, some
Web browsers do not support PNG images. PNG format
supports RGB, indexed-color, grayscale, and Bitmap-mode
images without alpha channels. PNG preserves transparency
in grayscale and RGB images. |
|
| TIFF |
| |
Tagged-Image File Format (TIFF)
is used to exchange files between applications
and computer platforms. TIFF is a flexible bitmap
image format supported by virtually all paint,
image-editing, and page-layout applications. Also,
virtually all desktop scanners can produce TIFF
images.
TIFF format supports CMYK, RGB, Lab, indexed-color,
and grayscale images with alpha channels and Bitmap-mode
images without alpha channels. Photoshop can save
layers in a TIFF file; however, if you open the
file in another application, only the flattened
image is visible. Photoshop can also save annotations,
transparency, and multiresolution pyramid data
in TIFF format. |
|
| PCX |
| |
PCX format is commonly used by IBM
PC-compatible computers. Most PC software supports
version 5 of PCX format. A standard VGA color
palette is used with version 3 files, which do
not support custom color palettes.
PCX format supports RGB, Indexed Color, Grayscale,
and Bitmap color modes, and does not support alpha
channels. PCX supports the RLE compression method.
Images can have a bit depth of 1, 4, 8, or 24. |
|
| WMF |
|
| EMF |
|
TGA |
| |
TGA (Targa®) format is designed
for systems using the Truevision® video board
and is commonly supported by MS-DOS color applications.
Targa format supports 16-bit RGB images (5 bits
x 3 color channels, plus one unused bit), 24-bit
RGB images (8 bits x 3 color channels), and 32-bit
RGB images (8 bits x 3 color channels plus a single
8-bit alpha channel). Targa format also supports
indexed-color and grayscale images without alpha
channels. When saving an RGB image in this format,
you can choose a pixel depth and select RLE encoding
to compress the image. |
|
| RAS |
| |
Sun Raster Image File Format |
|
| J2K |
| |
It is JPEG 2000 format.
The JPEG-2000 image compression system has a rate-distortion
advantage over the original JPEG. |
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