AVI Graphics Format Overview

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AVI Graphics Format Overview

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setting the biBitCount field in the BITMAPINFOHEADER of the DIB to 16 or
32. An uncompressed AVI file that stores images using the RGB 15, RGB
16, or RGB 32 color formats stores the video frames as DIB's using
these "new" color formats.

By default, the Microsoft 16 bit per pixel format is actually RGB 15
where one bit is unused, 5 bits for red, 5 bits for green, and 5 bits
for blue. This was done because the 15-bit RGB or 5-5-5 format was
used in 16-bit-per-pixel color video cards. Hardware designers found
it easier to build chips using a 5-5-5 pixel format with one bit
unused than the slightly higher resolution 5-6-5 color format.

The Microsoft 32 bit per pixel format has the most significant byte of
the pixel set to zero. Then 8 bits for red, 8 bits for green, and 8
bits for blue. This is RGB 32 bit. Why do this? The 32-bit pixels
in this format are DWORD aligned on 32 bit boundaries in this format
which is more efficient for operations and memory transfers under a 32
bit processor architecture than the unaligned 24-bit RGB format.

Microsoft also added a new value for the biCompression field of the
BITMAPINFOHEADER called BI_BITFIELDS. If biCompression is set
to BI_BITFIELDS, then the color table is three DWORD (32 bit)
masks giving the bits used for the red, green, and blue components
of a pixel. In this way, a "custom" format such as RGB 5-6-5 (5 bits
for Red, 6 bits for Green, and 5 bits for Blue) can be defined. This
is 16-bit RGB.

Although Four Character Codes (FOURCC's) such as 'RGB8' are used to
identify different Color Formats in some parts of Microsoft Windows,
the DIB data structures don't use FOURCC's, rather they use combinations
of biBitCount and biCompression.

In addition to 16-bit and 32-bit formats, Microsoft also defined a
mechanism for custom encodings such as YUV, YUY2, and so forth.
Manufacturers can register the new format with Microsoft. Microsoft
also concocted a JPEG-DIB specification for wrapping the JPEG still
image compression standard in a DIB. The JPEG DIB specification is
virtually unused, having lost to the JFIF JPEG file format. JPEG
images in general use, such as on Web pages, are JFIF's not JPEG
DIB's.

YUV Color Space and Color Formats

YUV is the color space used in the European PAL broadcast television
standard. PAL was originally introduced in Britain and Germany in
1967. PAL is used by most European nations and many nations around
the world. The United States and Japan use the NTSC standard. France
and a few other nations use the SECAM standard.

Y refers to the luminance, a weighted sum of the red, green, and blue
components. The human visual system is most sensitive to the luminance
component of an image. Analog video systems such as NTSC, PAL, and
SECAM transmit color video signals as a luminance (Y) signal and
two color difference or chrominance signals (the U and V above).

If, R, G, and B are the red, green, and blue values, then:

Y = 0.299 R + 0.587 G + 0.114 B

U = 0.493 (B - Y)

V = 0.877 (R - Y)

U is very similar to the difference between the blue and yellow
components of a color image. V is very similar to the difference
between the red and green components of a color image. There is
evidence that the human visual system processes color information
into something like a luminance channel, a blue - yellow
channel, and a red - green channel. For example, while we
perceive blue-green hues, we never percieve a hue that is
simultaneously blue and yellow. This may be why the YUV
color space of PAL is so useful.

To exploit this, digital color formats such as YUV9 or YUY2
exist that represent pixels as levels of Y, U, and V.

Summary

Both BMP still image files and AVI files may be saved in many
different color formats. While 24 bit RGB is almost universally
supported, there is no guarantee that your graphics software or
AVI playback drivers will support some of the less well-known
color formats. You may need to get special software, drivers, or
even hardware to use some of these formats.

For example, all of the color formats listed above are supported by
hardware and software drivers with the miro miroMEDIA PCTV TV Tuner
and Video Capture card. Some of these, like 8 bit grayscale Y8, are
not widely known or supported.

In general, video capture drivers allow selection of the color
format used when the video (AVI file) is captured. These color
format options should be accessible through the video capture software
application.

In Microsoft's VidCap and VidCap32 video capture applications, the
user may select the color format through Options | Video Format...

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Microsoft Run Length Encoding

Microsoft Run Length Encoding uses the Four Character Code MRLE

[drivers32]
VIDC.MRLE=MSRLE32.DLL

in Windows 95

[drivers]
VIDC.MRLE=MSRLE.DLL

in Windows 3.x

Microsoft Run Length Encoding usually appears with the
name "Microsoft RLE" in lists of Video Compression options.

8 BIT ONLY

Microsoft RLE only supports 8 bit color, a maximum of 256 colors using
a color lookup table. It does NOT support 16 bit color, also known as
"High Color" or "Thousands of Colors", or 24 bit color, also known as
"True Color" or "Millions of Colors".

WHERE TO GET Microsoft RLE

Historically, Microsoft RLE has been one of the standard Video for
Windows codecs from Microsoft.

The 16 bit Microsoft Video for Windows 1.1e installs a 16 bit
version of the Microsoft RLE video codec.

The Microsoft Windows 95 CD-ROM installs a 32 bit Microsoft
RLE video codec.

The Microsoft Windows NT Workstation Operating System Version 4.0
installs a 32 bit Microsoft RLE video codec.

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Microsoft Video 1

Microsoft Video uses the Four Character Code MSVC

[drivers32]
VIDC.MSVC=MSVIDC32.DLL

in Windows 95

[drivers]
VIDC.MSVC=MSVIDC.DLL

in Windows 3.x

NOTE: The Four Character Code CRAM is also used for Microsoft Video 1.

8 OR 16 BIT ONLY

Microsoft Video 1 supports only 8 bit or 16 bit color. 16 bit color is
also known as "High Color" or "Thousands of Colors". Microsoft Video 1
does not support 24 bit color, also known as "True Color" or "Millions of
Colors".

WHERE TO GET Microsoft Video 1

Historically, Microsoft Video 1 has been one of the standard
Video for Windows codecs from Microsoft.

The 16 bit Microsoft Video for Windows 1.1e installs a 16 bit
version of the Microsoft Video 1 video codec.

The Microsoft Windows 95 CD-ROM installs a 32 bit version of the
Microsoft Video 1 video codec.

The Microsoft Windows NT Workstation Operating System 4.0 CD-ROM
installs a 32 bit version of the Microsoft Video 1 video codec.

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Intel Real Time Video 2.1 (Indeo 2.1?) (RT21)

RT21 is the Microsoft Four Character Code for the Intel Real Time
Video 2.1 (Indeo 2.1?) video compressor-decompressor (codec).
Microsoft's 16-bit Video for Windows Version 1.1e for Windows 3.x
includes a 16-bit Video for Windows codec for RT21.

WHERE TO GET Intel Real Time Video 2.1

Microsoft appears to have discontinued support for RT21 in the
32-bit Video for Windows in Windows 95 and Windows NT 4.0. There are
32-bit Video for Windows codecs for Indeo 3.1/3.2, Indeo 4.x, and
Indeo 5.0.

For example, the Microsoft Windows NT Workstation Operating System
Version 4.0 CD-ROM DOES NOT install RT21. It DOES install Intel
Indeo R 3.2

See the Where to get the 16-bit Video for Windows
section.

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Intel Indeo 3.1/3.2

Indeo uses the Microsoft Four Character Codes IV31 and IV32,
originally for Indeo 3.1 and Indeo 3.2, but these are usually now
mapped to Indeo 3.2

[drivers32]
VIDC.IV31=IR32_32.DLL
VIDC.IV32=IR32_32.DLL

in Windows 95

[drivers]
VIDC.IV31=IR32.DLL
VIDC.IV32=IR32.DLL

in Windows 3.x

Indeo 3.x uses Vector Quantization based image compression.

WHERE TO GET INDEO 3.x

Indeo R3.2 is one of the default standard Video for Windows codecs.

Microsoft's 16 bit Video for Windows 1.1e includes a 16 bit Indeo 3.2
codec (the IR32.DLL above).

The Microsoft Windows 95 CD-ROM installs a 32 bit Indeo 3.2 video codec.

Microsoft Windows NT Workstation Operating System 4.0 CD-ROM installs
a 32 bit Indeo R3.2 video codec.

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Cinepak

Cinepak is the most widely used Video for Windows codec. Cinepak
reportedly provides the fastest playback of video. While Indeo 3.2
provides similar or slightly superior image quality for same
compression, Indeo decompression is much more CPU intensive than
Cinepak. Cinepak was originally developed for the Mac and licensed to
Apple by SuperMac Technology Inc. It is now free with Video for
Windows. It is also free with Apple's QuickTime.

There are at least three Cinepak Video for Windows codecs in existence:

Cinepak by SuperMac (the original, 16 bit)
Cinepak by Radius (newer, better?, 16 bit)
Cinepak by Radius[32] (32 bit version of Radius Cinepak, shipped with Windows 95)

Peter Plantec's Caligari TrueSpace2 Bible strongly recommends using
the Radius codec for superior results when generating AVI files from
TrueSpace.

Cinepak uses the Microsoft Four Character Code CVID

[drivers32]
VIDC.CVID=ICCVID.DLL

in Windows 95

[drivers]
VIDC.CVID=ICCVID.DRV

in Windows 3.x

Apple QuickTime supports Cinepak.
Mark Podlipec's XAnim Unix X11 video player supports Cinepak.

Cinepak uses Vector Quantization based image compression and frame
differencing.

Historical Note: On or about Jan. 6, 1999, Radius Inc. renamed itself
Digital Origin Inc.. SuperMac Technology, the original owner
of Cinepak, was a predecessor to Radius.

WHERE TO GET CINEPAK

Cinepak is one of the default standard video codecs in Video for Windows.

A 16-bit version of Cinepak is included in the 16 bit Video for Windows 1.1e

The Microsoft Windows 95 CD-ROM installs a 32 bit Cinepak by Radius video
codec.

Microsoft Windows NT Workstation Operating System Version 4.0 CD-ROM installs
a 32 bit Cinepak by Radius video codec.

CINEPAK PRO

Compression Technologies Inc.
Oakland, CA
E-Mail: info@cinepak.com
http://www.Cinepak.com/

sells an improved Cinepak compressor that purportedly can fix
some common problems with video encoded with Cinepak. They
say their product, CinepakPro, generates 100 percent completely
Cinepak compatible movies. These movies will play back using all
existing native Cinepak decompressors.

CinepakPro and Cinepak Toolkit (Macintosh OS 7.5 or newer and
QuickTime 2.5 or 3)

CinepakPro QTX (Windows 95/98/NT and QuickTime 3.0 for Windows)

CinepakPro AVI (Windows 95/98/NT and Video for Windows/
ActiveMovie)

An updated AVI Cinepak codec for Windows is available at the
Compression Technologies Inc. Web site (May 12, 1999).

Vector Quantization

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Motion JPEG

Most PC video capture and editing systems capture video to AVI
files using Motion JPEG video compression. In Motion JPEG, each
video frame is compressed separately using the JPEG still image
compression standard. No frame differencing or motion estimation
is used to compress the images. This makes frame accurate
editing without any loss of image quality during the editing
possible.

The standards situation for Motion JPEG is complicated since
at one time there was no industry standard for Motion JPEG.
Microsoft has a Microsoft Motion JPEG Codec and a JPEG DIB
Format. The OpenDML Avi File Format Extensions (another
standard for extending AVI to support professional video
features) includes Motion JPEG support. See the Paradigm
Matrix site below for more information on these standards.

Motion JPEG codecs usually use the Four Character Code 'MJPG'.

Motion JPEG is used for editing and authoring, but rarely for
distribution. Usually, once the video has been edited, it is
compressed further using Cinepak or another codec for distribution.
Because Motion JPEG does not use frame differencing or motion
estimation, better compression is possible with other codecs.

A software Motion JPEG codec for Windows NT and Windows 95 is available
from Paradigm Matrix at:

http://www.pmatrix.com/Goodies.htm

The Paradigm Matrix Motion JPEG codec uses the Four Character Code
MJPG.

A 32-bit software Motion JPEG codec for Windows NT and Windows 95 is
available from Morgan Multimedia at:

http://www.morgan-multimedia.com/

A 32-bit software Motion JPEG codec for processors with MMX instructions
(MainConcept Motion JPEG Codec) is available from MainConcept at:

http://www.mainconcept.com/

Motion JPEG uses the Block Discrete Cosine Transform (DCT) for
image compression.

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Editable MPEG

At least two companies defined schmes to wrap editable MPEG (I frames
only MPEG) in AVI files. Xing Technology's editable MPEG AVI uses
the Four Character Code XMPG. Sigma Designs defined an AVI format
using the Four Character Code MPGI.

Editable MPEG consists of only MPEG I frames. This omits the MPEG
motion estimation. It is very similar to Motion JPEG. By wrapping
I frames only MPEG in AVI, editable MPEG works with standard Video for
Windows editing and authoring applications such as Adobe Premiere.

Xing Technologies
http://www.xingtech.com/

Sigma Designs
MPEG Extensions to AVI File
Format (Draft 1.1 by Sigma Designs)

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The New Wave

Recently (5/18/97), there has been a proliferation of new Video for
Windows codecs. A few like H.261 have been around for a while, but
most represent implementations of new or improved technologies such as
wavelets. Many are targetted toward low bitrate video over the
Internet. For lack of better terminology, I refer to these as the New
Wave to differentiate them from the older codecs like Cinepak included
with Video for Windows 1.1e (the last release prior to Windows 95).

Microsoft appears to be developing or licensing some of these codecs as part of
NetShow, NetMeeting, and other Microsoft initiatives.

VDOWave or VDOLive from VDONet

VDONet http://www.vdo.net/
4009 Miranda Ave., Suite 250
Palo Alto, CA 94304
Voice: (415) 846-7730
FAX: (415) 846-7900

markets a wavelet based video codec which includes a Video for Windows
(32 bit) implementation. Microsoft has licensed VDOWave as
part of the NetShow product. There are two versions of the
VDOWave codec. VDOWave 2.0 is a fixed rate video codec which uses
the Microsoft Four Character Code VDOM. This codec adds the line

[drivers32]
vidc.vdom=vdowave.drv

to the SYSTEM.INI file in Windows 95.

VDOWave 3.0 is a "scalable" video codec. This codec uses the Microsoft Four
Character Code (FOURCC) VDOW and adds the line

[drivers32]
VIDC.VDOW=vdowave.drv

to the Windows 95 SYSTEM.INI files.

In NetShow 2.0, the standalone Client Setup installs a VDOWave
decode-only codec. The NetShow 2.0 Tools Setup installs a
VDONet VDOWave encoder.

In some of my tests, VDOWave appears significantly superior to MPEG-1
and the other block Discrete Cosine Transform based codecs at low
bitrates.

VDONet uses the trademark VDOWave for its wavelet based video codec.
VDONet uses the trademark VDOLive for its VDOLive On-Demand Product
Line. This includes the VDOLive On-Demand Server, the VDOLive tools
including VDOCapture and VDOClip, and the VDOLive Player. Sometimes
VDOLive and VDOWave are used interchangably by users and in some company
literature.

VDONet also has a VDOPhone product for real-time videoconferencing.

Based on the company documentation, published reports, and viewing the
technology, VDOWave appears to be a combination of wavelet based image
compression and motion compensation or frame differencing.

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What is Indeo Video Interactive?

Indeo Video Interactive, Indeo 4.1, is a new version of Indeo from
Intel based on a "hybrid wavelet algorithm" according to Intel. This
is a different compression algorithm than Indeo 3.2 which is included
with Video for Windows. Indeo 3.2 uses Vector Quantization.

Indeo Video Interactive supports a number of features in addition
to the new compression algorithm such as transparency.

Indeo Video Interactive can be installed as a Video for Windows
codec or in the new ActiveMovie environment from Microsoft.

For further information on Indeo Video Interactive

http://www.intel.com/pc-supp/multimed/indeo/index.htm

How to program "sprites" in Indeo Video Interactive?

Some of Intel's marketing material touts the ability to
add sprites to applications using Indeo Video Interactive.
Most of Intel's technical documentation on Indeo and the API's
for using Indeo Video Interactive neglects to explain what Intel
means by "sprite". There is a brief mention in the Overview
document for Indeo Video Interactive.

Indeo "sprite" means TRANSPARENCY.

Indeo Video Interactive supports TRANSPARENCY. Indeo has
transparent pixels to create transparent backgrounds to
implement effects such as chroma-keying. The well-known
example of chroma-keying is the television weather forecaster
standing in front of a satellite weather picture. The forecaster
stands in front of a blue screen (sometimes a green screen) and
video gadgetry replaced the blue color with another video signal.
Anything that is not the blue "key" color is left unchanged.

In Indeo jargon a "video sprite" is a foreground object such as the
mythical weather-caster on a transparent background. Your application
can then provide a bitmap image or even another video as a background
in the transparent areas of the image. This provides a crude
mechanism for the video to change depending on interactions with
a user.

Look up the API's in Intel's documentation for TRANSPARENCY
to implement video sprites.

How to identify an AVI file that uses Indeo Video Interactive
for the video compressor?

Video for Windows identifies different video compressors through
four character codes. For example, 'cvid' is the four character
code for the widely used Cinepak compressor. The four character
code is found in the video stream header 'strh' in the AVI file.

Indeo Video Interactive (Indeo 4.1) uses the four character code
'iv41'

If Indeo Video Interactive is not installed installed Video for
Windows will report an error, indicating that it cannot find the
compressor for 'iv41'. The specific message appears to be:

"Video not available, cannot find 'vids:iv41' decompressor."

NOTE: Indeo 4.1 claims to implement a hybrid wavelet transform.
Some of the behavior of the codec at low bitrates differs from other
wavelet based image and video compressors such as VDOWave, Infinop's
Lightning Strike, and some public domain wavelet compression software.
In particular, at low bitrates, I have seen the characteristic checkerboard
pattern of 8x8 pixel blocks seen in block based transform coding methods such
as MPEG-1. I'm not sure what Intel means by hybrid wavelet transform.

In general, at low bitrates, image and video compression schemes using the
Discrete Wavelet Transform (DWT) exhibit a blurring at the edges of objects and
also "ringing" artifacts near edges. They do not exhibit the blocking
artifacts, checkerboard pattern in extreme cases, seen in block Discrete Cosine
Transform based image and video compression.

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Indeo Video Interactive 5.0

Intel is now (2/22/99) distributing an Indeo Video Interactive 5.10
software on their Web site. Indeo 5.0 claims to use a new better
wavelet compression algorithm for improved video quality. Indeo 5
includes features such as progressive download for the Internet,
transparency, sprites, etc.

As of 2/22/99, the latest version of Intel Indeo Video appears to
be Indeo Video 5.10. The latest version of Intel Indeo Audio appears
to be Indeo Audio 2.5

The previous version of Intel Indeo Video was Indeo 5.06

http://developer.intel.com/ial/indeo/video/

Known releases of Indeo Video 5.x

Intel Indeo 5.10 (02-Feb-1999)
Intel Indeo 5.06 (1998)
Intel Indeo 5.0 (1997????)

NOTE: All releases of Indeo 5.x appear to use the Four Character
Code IV50

Apple QuickTime 4 includes support for Indeo 5, allowing playback on
Apple Macintosh platforms.

http://www.apple.com/quicktime/technologies/indeo/

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ClearVideo (aka RealVideo)

ClearVideo is a video codec from Iterated Systems( http://www.iterated.com

Iterated has also licensed the ClearVideo technology to Progressive
Networks, makers of RealAudio, under the name RealVideo.

You can (or could at one time) download a Video for Windows demo of
ClearVideo from the Iterated Web site. This includes a demo Video for
Windows codec that allows both encoding and decoding The video can
only be played on the same machine with the demo encoder. This codec
works with Video for Windows applications such as Media Player and
VidEdit.

Fractal video encoding appears to be very slow (computationally
intensive). The video is similar or somewhat
superior to MPEG-1 in quality.

ClearVideo uses Fractal Image Compression. Iterated is the main
(only?) producer of commercial fractal image and video compression
technology.

The Video for Windows evaluation version of ClearVideo
installs

[drivers32]
VIDC.UCOD=CLRVIDCD.DLL

in SYSTEM.INI in Windows 95.

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SFM (Surface Fitting Method)

Crystal Net Corporation (http://www.crystalnet.com/ seeks
to license a technology called SFM or Surface Fitting Method. This is
supposed to be a low bitrate video technology for ISDN and POTS (Plain
Old Telephone Service) bitrates. They have a Video for Windows demo
to download from their Web site.

SFM used the Microsoft Four Character Code (FOURCC) SFMC.

The demo installs (actually the instructions tell you to manually install):

[drivers32]
VIDC.SFMC=SFMdemo.dll

in Windows 95.

The demo does not include an encoder which presents problems in evaluating
the technology. However, SFM appears to be some sort of edge detection based
encoding technology.

White Pine's Enhanced CU-See Me desktop videoconferencing product uses
Crystal Net's SFM under the name White Pine Color Software Codec.
NEC has reportedly licensed SFM for its Network Video Audio Tool (NVAT).
(February, 1998)

Crystal Net also reportedly has relationships with Shepherd Surveillance
and Winnov. (February, 1998)

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QPEG

Q-Team Dr. Knabe produces a Video for Windows codec known as QPEG.
Currently (6/27/97), QPEG supports 8 bit color. Q-Team plans 16 and
24 bit color, MMX support, and other additional features in the
future.

Sample AVI/QPEG files and Video for Windows QPEG codecs for
Windows 3.x and Windows 95/NT are available at the Q-Team
Web site.

http://www.q-team.de/

Q-Team is also working on MPEG-4 for the PC.

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H.261

H.261 is an international standard, widely used for video conferencing
in the 128 Kbits/second to 384 Kbits/second range. This is a block
Discrete Cosine Transform method. Actually, H.261 was the first
international standard developed using the block Discrete Cosine
Transform and motion compensation. MPEG-1, which is probably better
known, followed the H.261 effort.

Intel's ProShare videoconferencing product installs a Video for Windows H.261 codec.

NOTE: I've never generated an AVI files with Intel's H.261, so it
may only be used for Intel ProShare videoconferencing and not with AVI.

Microsoft has a Microsoft H.261 Video for Windows 32 bit codec.

[drivers32]
VIDC.M261=MSH261.DRV

in Windows 95.

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H.263

H.263 is another international standard, based on the Block Discrete
Cosine Transform (DCT) and motion compensation. H.263 has a number of
improvements, mostly in the area of motion compensation, over the
earlier H.261 standard. It is targeted toward very low bitrate video
compression.

Microsoft's NetShow 2.0 installs a Microsoft H.263 video codec.
Microsoft H.263 uses the Four Character Code M263.

[drivers32]
VIDC.M263=msh263.drv

in Windows 95.

The Microsoft H.263 video codec is one of several "keyed" codecs
installed by NetShow. Others are Vivo H.263 and Duck's TrueMotion 2.0.
These codecs will not encode video as AVI files, although they
apparently will create Microsoft ASF files or provide compression for
streaming video products such as Microsoft's NetMeeting
videoconferencing. See the section on NetShow for more information
on the NetShow video codecs.

Some versions of the msh263.drv driver will crash when trying to
encode an AVI file from VidEdit or similar applications. Other
versions of msh263.drv don't crash but give an "Unable to begin
compression" message box.

Vivo Software Inc. markets streaming H.263 and G.723 audio for the
Web under the brand name VivoActive. Vivo has its own file format
called .VIV which can be embedded in Web pages. Vivo provides
a player called VivoActive player and an authoring tool for
creating .VIV files called VivoActive Producer.

Microsoft NetShow installs a "keyed" codec that identifies itself as
Vivo H.263 Video Codec[32] which installs

[drivers32]
VIDC.VIVO=IVVIDEO.DLL

in Windows 95. Vivo H.263 uses the four character code 'VIVO'.

The Vivo Software Web Site:

http://www.vivo.com/

Intel distributes an Intel "I263" H.263 video codec at there Web
site as part of the NetCard product. This installs

[drivers32]
VIDC.I263=C:\WINDOWS\I263_32.DLL
VIDC.I420=C:\WINDOWS\I263_32.DLL

in Windows 95.

As of June 18, 1998, this codec could be found at:

http://support.intel.com/support/createshare/camerapack/CODINSTL.HTM

Note that Intel, like Microsoft, seems to rearrange their Web site
constantly.

Unlike the keyed Microsoft H.263 video codecs, this codec can be
used to encode AVI's through Microsoft VidEdit 1.1 (and presumably
other video editing products). How well this codec in fact
implements the H.263 standard is not clear.

Shannon Communication Systems (SCS) has an H.263+ AVI codec and
analysis tool available for download at their Web site:

http://www.shansys.com/

Telenor R&D of Norway distributes the source code for an H.263 encoder
and decoder that will reportedly compile and run under Windows. This
is a standalone application not a Video for Windows codec or
ActiveMovie filter. See elsewhere in the AVI Overview for a link to
the Telenor Web site.

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MPEG-4

Microsoft's NetShow 2.0 installs a Video for Windows codec for
MPEG-4. MPEG-4 is a new international standard that has not
been officially released as yet. Microsoft is deeply involved in
the MPEG-4 standardization effort. Microsoft has been using
its MPEG-4 for the Microsoft NBC Business Video broadcasting over
the Internet.

The Microsoft MPEG-4 Video for Windows Codec identifies itself
as "MPEG-4 High Speed Compressor" in Control Panel | Multimedia |
Devices | Video Compression Codecs.

Adding to confusion in true Microsoft fashion, there are two
versions of each NetShow video codec. The NetShow 2.0 Player (Client)
installation program installs codecs that provide only decoding
functionality. The MPEG-4 video codec installed by NetShow 2.0 Player
can only play back an MPEG-4 AVI. The MPEG-4 video codec installed by
the NetShow 2.0 Tools can encode AVI files with MPEG-4 video
compression.

If you want to author MPEG-4 compressed AVI, make sure to get and
install the NetShow 2.0 Tools, not just the NetShow 2.0 Player.

The Microsoft MPEG-4 High Speed Compressor Video Codec installed
by the NetShow 2.0 Tools will not encode arbitrary dimension
video. The video must have the dimensions 176 x 144 (QCIF).
In Microsoft VidEdit, "MPEG-4 High Speed Compressor" becomes
visible in the list of compression options only if the video
is sized to 176x144.

MPEG-4 uses the Microsoft Four Character Code (FOURCC) MPG4.

[drivers32]
VIDC.MPG4=msscrc32.dll

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Lightning Strike (Infinop)

Infinop markets a wavelet based video codec called Lightning Strike
Streaming Video. A Lightning Strike video decoder compatible with
Microsoft NetShow can be dowloaded from the Infinop Web site. There
are several sample Lightning Strike Video files at the Infinop
site. The Lightning Strike encoder does not seem to be generally
available.

http://www.infinop.com/

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VxTreme

VxTreme was acquired by Microsoft in September of 1997.
Microsoft has invested in numerous low bitrate audio and video
companies during the second half of 1997, include VxTreme, VDONet,
Progressive Networks/RealNetworks, and Lernout and Hauspie Speech
Products.

Although I have not seen a Video for Windows implementation of VxTreme
(12/20/97), I thought that I should include this codec. Undoubtedly,
it will be ported to Video for Windows and/or ActiveMovie if this has
not already happened.

VxTreme(http://www.vxtreme.com/
markets a video codec that is usually identified as a wavelet based
codec.

A VxTreme player, a Plug-In for Internet Explorer and Netscape, is
available at the VxTreme Web site.

VxTreme has some very impressive demos of QCIF (160x120) talking heads
material on their Web sites. The subjective image quality during
scenes with small changes is quite good, much superior to the block
Discrete Cosine Transform based codecs and probably VDONet's VDOWave.
Text such as movie titles and credits appears to encode very well.
Preserving the sharp edges of text is a major problem in block
Discrete Cosine Transform based encoders such as the JPEG still image
compression standard and the MPEG video compression standard. In
general, wavelet image compression encounters problems with sharp
edges as well.

VxTreme clearly uses some sort of motion compensation or frame
differencing. Image quality drops dramatically during periods with
rapid changes. I viewed a number of movie trailers encoded with
VxTreme for 28.8 Kbits/second such as the trailer for "Goldeneye".
These trailers contain many scene changes and motion. Video quality
is poor, hardly superior to competitors such as H.261 or Microsoft's
MPEG-4. The talking heads material at 28.8 looks almost natural.

VxTreme may be a combination of the Discrete Wavelet Transform (??)
and motion compensation. The preservation of sharp edges suggests
something beyond the vanilla Discrete Wavelet Transforms described in
the technical literature on wavelet based image and video compression.

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