Take a look at
MJPEG-Software-Codec Guide by Uwe Roeder, a very interesting text about
using software codecs coexisting with a Matrox Rainbow Runner.
About the Morgan Multimedia and Paradigm
Matrix M-JPEG codecs
This text is written for all people who
want to use other MJPEG-codecs with their RR.
What is a codec and how does
it work ?
Why should you use another/additional codec ?
What are the
What on earth is a codec ? (Or how does my
RainbowRunner work ?)
If you want to process a video, you first have to
record/capture to a digital video file. With the RR you can choose between
recording to a RGB-avi or to a Matrox-MJPG-avi file. The result of your
capturing is a video file in the AVI-format with RGB or MJPEG as subformat. The
RGB format is a format where the picture data keep uncompressed. On the one hand
this means best quality, but on the other hand you have a very high data-rate
during capturing/playing and the files are very large. The pictures of MJPEG-avi
files are compressed and because of that this format is the better way for us to
handle video-files on our PC.
The files need less place on the harddisk and
even the data-throughput between harddisk and RR is smaller. Well ok, the
quality is less, too, but we can choose our compromise between quality and
The compression is done during capturing in realtime by a
Zoran-chip on the RR. Your captured video file contains an identifier (called
FourCC) in itï¿½s header that shows the subformat. For Matrox-MJPEG the identifier
tag is "dmb1". If you open a avi file, the Video-for-Windows routines
examine the avi file header and read this identifier tag at first.
have a look in the system.ini to the [drivers32] section and watch the VIDC.xxxx
settings to see which driver must be used to process the file.
Matrox-MJPEG-codec can be found at VIDC.dmb1=....RRicm.dll. Whenever you want to
play a Matrox-MJPEG-avi with the MediaPlayer or you want to process it with any
video-editing software, this driver ,called codec, will be activated for
decompressing the pictures.
After processing your avi, when creating a new
avi, the video-editing software lets you choose one of the VIDC.xxxx codecs to
(re)compress the data.
The identifier-tag of that codec will be written into
the aviï¿½s file-header. If you compress (and save) your file with the
Matrox-MJPEG-codec the id-tag is "dmb1" again, but if you have chosen
e.g. the "Indeo 5.0"-codec, the id-tag will be "IV50".
Interesting excursion: If you disable the VIDC.dmb1
setting by inserting a semicolon before itï¿½s entry in the system.ini, the
video-editing software will still be able to handle avi-files with the dmb1-tag,
and both the ActiveMovie-Player and the Matrox PC-VCR software can play and
output those files ! We even can record avis with the PC-VCR and other capture
programs without the system.ini entry.
OK, let us draw some conclusions. Whenever we record a
MJPEG-avi file with the RR it contains the dmb1 tag independent of any
The ActiveMovie-routines (and all programs making use
of them like Matrox PC-VCR, MediaStudio 5, etc.) use the hardware
decompression (Zoran-chip) for all MJPEG-compressed avi files containing the
dmb1 (Matrox) tag independent of any system.ini settings, too. Letï¿½s keep in
mind that the MJPEG-format is a standard format and not a special Matrox format.
Why should I use another codec ?
If you are satisfied with your system and with the
results of your work with the RR, I guess there is no need to change the system.
The Morgan- and the Paradigm-codec produce MJPEG-avi files
(with a higher quality and certainly higher data-rate if you want). If your
system is fast enough, you can improve the quality of your videos and reduce
artefacts. Some actions are faster with those codecs and some not...
recommend to use the Morgan Multimedia codec because of itï¿½s better quality. You
have many possibilities to influence the performance and quality of this codec
by choosing between different numerical methods and activating hardware support
There are two groups of RR-users who should use one of the
software codecs. Windows NT users and users of a Millennium II+RR having trouble
with the "snowy-frames" problem. Windows NT users suffer from the
NT-driverï¿½s lack of MJPEG-support. With the software-codecs they get the
possibility to process and playback their MJPEG-videos in NT. They still have to
record the MJPEG-videos with Windows 9x.
The "snowy-frame" problem
is a bug in the Matrox-MJPEG-codec, which appears on some Millennium II+RR
systems. If a program opens a Matrox-MJPG avi and getï¿½s the pictures to
recompress them or to show them in the timeline (MSP5/Premiere) the codec
produces corrupted (snowy) frames although the avi-file is ok.
There are some different ways to install the drivers
depending on your needs.
At first you have to install the additional codec(s).
(Paradigm: Do not use the secondary setting.)
After that you have many
possibilities how to combine the codecs in your system.
You can replace the Matrox-codec by the Morgan-codec
You must make the following changes to the system.ini:
The driverï¿½s "user
FourCC"-field must be enabled and set to "dmb1". After
that you can work with your RR like before but without "snowy-frames"
and with better quality ("Integer" or "Float" method for
"Compression" in Morgan codec settings and "Higher Quality"
in Paradigm codec settings) . You donï¿½t have to patch any avi-files. Avi-files
played with ActiveMovie, Matrox PC-VCR or MSP5 (best Preview) make use of the
RRï¿½s hardware-accelleration and can be recorded on tape etc.
You can replace the Matrox-codec by the
You must make the following changes to the system.ini:
And you must make an additional entry to the registry with
HKEY_CURRENT_USER\Software\Paradigm Matrix\Software M-JPEG Codec
Entry: Compress FourCC=31626d64 (hex)
64=d 6d=m 62=b 31=1 => 31626d64=dmb1
The Matrox-codec is disabled and the Paradigm-codec is
made responsible for all avi-files with the Matrox dmb1 identifier tag.
you record to a MJPEG-file the dmb1-tag is set by the Matrox capture driver
indepent from these settings. If you process your videos with MSP5 or Premiere
the Paradigm-codec is used to decompress the files. If you create a new avi-file
from your video-project and choose the Paradigm-codec, the registry setting
makes the Paradigm-codec write the Matrox dmb1-tag in the avi header. You can
play your new file with the Matrox PC-VCR with the hardware acceleration of the
With this setting it is very simple to work. You have to install the
driver, edit the system.ini and registry once and you will not have to change
any settings or fileheaders in future. You only have to remember that your new
processed file canï¿½t be longer than 2 GB in order to be played with the RR. I
tried to play a video project with the MSP 5, but I didnï¿½t manage it. I only was
able to create a avi-file. This limitation is a great disadvantage. If you are
processing only small files, this is no problem for you and this way works fine.
You can use the Morgan- and the Paradigm-codecs as
Your system.ini entries must look like the following:
Matrix\Software M-JPEG Codec\
Compress FourCC = 32626d64 (hex)
This value stands for 'dmb2' ! Don't confuse with 31626d64
for 'dmb1' !!!
The Morganï¿½s "user FourCC"-field has to be
disabled or if you like to enable it set it to "MJPG". If you use
avi.exe you must change the content of the Morgan-button from "mjpg"
to "MJPG". "mjpg" was used in earlier driver versions but it
has changed to "MJPG" because of the specs.
All codecs are active and can be used to decompress and
compress avi-files. You can define which codec will be used for which file by
changing the identifier tag in the file header of each file. If you want the avi
to be decoded by the Matrox-codec the identifier tag must be "dmb1".
If you want it to be decompressed by the Paradigm-codec the id-tag must be
"dmb2" and "MJPG" for the Morgan-codec. You should use the
avi.exe Windows program to change the identifier.
You can play your
video-projects with MSP and do not need to create avi-files. So you are not
limited to 2 GB with your projects. If you want to create avi-files from your
project you can choose the compression. This can be the Matrox, Morgan, Paradigm
(all MJPEG) or some other codec (like Intel Indeo).
If you have
chosen the Morgan- or Paradigm-codec, your generated avi-file contains the dmb2
or MJPG identifier in the file-header. You must change this with avi.exe to dmb1
(Matrox) to play the file with the RRï¿½s hardware accelaration. Otherwise the
file will be played back only with the power of your CPU and it could be, that
your system is not fast enough for 25/30 fps.
For playback it is better to
use the Matrox-identifier; for further processing you should use the other
identifiers. The disadvantage of this method is the changing of the file-header,
but I think that this is no problem with avi.exe. The advantage is the great
flexibility, because you can decide which codec will be used for a file.
General info about using the other
When creating avi-files from your video-projects with
the any codec, you can choose the compress-quality with a slider. If you want
the avi be processed with other programs later, you can choose the maximum
setting, but you have to be aware of the longer filesize and greater data-rate.
It could be that your system is not fast enough to playback those avis in
You must keep in mind that the MJPEG format is a
compression format. MJPEG stands for Motion JPEG. I guess all of us have used
pictures in the JPEG (.JPG) format. The file size is very small after converting
a tiff (uncompressed) to JPG and the quality is decreased. The more you compress
the less is the quality.
When we use MJPEG we must know that we pay for the
small file size and the smaller datarate with picture-quality. This is typical
for the JPEG-compression.
If you want to increase the quality of your captured
videos you can try to use Doc Mordridï¿½s overclocking method, which is described
at TIGRR. If you are not
familiar with editing the registry you can use the tool MJPG.EXE to change the
Last edited 19.11.1998 by Uwe Roeder.