Codecpage News
WindowsMedia Audio8/Video8
Upside
down
Use
VirtualDub with WM8
MS has meanwhile released WM9. It's still
extremely hard to get anything done with the official encoder,
but MS has also released a WM9 VCM codec that can be used directly in VirtualDub,
as easy as DivX.
So you may follow any VirtualDub/DivX guides for WM9 encoding
as well. I leave the (trickier) WM8 guide here for documentary
purposes.
I've done a series of tests with the MS WindowsMedia8 encoder.
This codec can also make very small files, but I've concentrated these tests on best possible quality.
So I tried some extremely wild and difficult
TV takes (but without extremely fast linear motion, see below)
in 704x576, and they worked very well with 1500 kbps (CBR looked
better than VBR, which flawed at calm moments; only 2-pass VBR
is a bit better but encodes extremely slow). More tests showed
that changing the crispness setting or increasing the bitrate
did not really improve things any more. 1500 kbps CBR is close
to the optimum value for this frame size and this codec.
MS MPEG4 (not so DivX4/5 !) would have glitched with these large
frame files at any rate.
Even CPU usage was smaller at playback than with an MS MPEG4 of
this material (MediaPlayer7).
Not only that, interlacing was no problem (this already worked
with MPEG4, see here
why), this looks great on my Matrox TV output.
Other improvements: DV files now work as input, and files >4
GB are no problem.
Last but not least, no crashes so far.
The final torture test however, it did
not pass:
Bumpy old Hi8 video shot from a fast moving car, sideways out
of the window at 1/1000 s shutter speed, giving some strobe effect
but looking fluent and crisp in the original.
At this, the encoder glitched at any bitrate, CBR and VBR.
DivX4 can do this, with properly deinterlaced source and 2-pass
VBR. Also a DivX;-)3.xx encoding with nandub already behaves better.
WIth WM8, CBR was still the better trade. In CBR, the encoder
seems not even to try to fully encode these sequences, because
pictures staggered while CPU load at playback decreased
dramatically. This effect is also known from MS MPEG4, but there
it occurs even much earlier. It seems that the motion search of
these codecs is a bit short sighted, because the problem is also
present with non interlaced material and seems to be confined
to cases where very fast linear movements occur . It must also
be sort of a bug, because it's not understandable that apparently
encoding fails to deliver any content in these cases. Using 2-pass
VBR works a bit better but in my extreme test video fast parts
are still a bit jerky while calm ones are blurry, grass looking
like green slime.
The only encoder that really can handle this excelently is still
TMPGenc (MPEG2). It outperforms even DivX4 then, because MPEG2
can handle interlaced video easily and therefor preserves all
of the motion reolution. At about 3000 kbps avg. (1/3 DVD standard
rate), this is viewable to excellent and, most important, it's
fluent. Use 2-pass VBR (bitrates 1000/3000/9000) and motion search
'normal' for good results. At this bitrate, I would estimate that
TMPGenc has about the same compression ability as WM8, even with
better motion behavior. Only that it cannot be forced to work
properly below 2500 kbps for full frame MPEG2.
The most convenient way to use the Media8
encoder is WME8GUI (I've done all tests with it). The homepage
of the author is gone, but you may still find it at doom9.
I've also managed to let VirtualDub frameserve (striped AVI method,
see below) to the
Media8 encoder, so one can cut and filter MJPEG TV recordings
best way possible and send them to the encoder without recompression.
This way, the restriction to the wmv format is not so important
if this is intended to be the final cut.
I haven't yet got it to work with any crop/resizing filters in
VirtualDub (which is less important because Media8 encoder has
its own). Others work well.
By using dvd2avi and vfapi converter (see links), transfer from
MPEG2 to WM8 is also possible. You may even be able to frameserve
from dvd2avi to VirtualDub to WM8 to include filtering.
Recommendation: use MediaPlayer 7 for playback, not 6.4. Apparently
it uses a different filter path, CPU usage was 20% lower and playback
much smoother.
Besides, this codec also does not work with the Matrox TV-out at 720 wide (Like MPEG4 and MJPEG; MPEG2 and DV do work). See links for a utility to cure this (Not as ideal for WM8 because it only works with MediaPlayer 6.4).
Conclusion: This new codec set from MS
is really impressive. It can deliver the same quality as the old
MS MPEG4 codecs, at about half the bitrate. handling of large
frame sizes and turbulent scenes has improved, also the cleanliness
of calm scenes. Steady fast movements however are still able to
make it glitch. Above 2500 kbps, MPEG2 made with TMPGenc is better.
I have not yet tested low bitrate applications (however I'm sure
it will also be very good at that).
Upside Down
You may experience that MPEG4-files come
out upside down when recompressed with Media8 encoder.
The help file of the utility advises to change a certain registry
key in that case. You may also have to change this key back, so
this is tedious. I've prepared 2 .reg files that you just double
click on to make the changes. Download here.
Here's how to set up VirtualDub frame serving under Windows2000/XP:
First, Start Auxsetup.exe to install auxiliary setup.
Read the Advanced/Frameserver chapter
in VirtualDub's help file, about installing and using VCM.
For Win95/98, just do what's written there, but for Windows2000
it's a bit different.
The following is for Windows2000 and XP only:
Copy the files vdsrvlnk.dll and vdicmdrv.dll to \Winnt\System32
Do not edit system.ini but register the
dll in the registry. You may do this by double clicking on VCM.reg
in this archive (right
click to view/edit contents of a .reg file). No reboot necessary.
I've also prepared the vd.stripe file for you (in the same archive).
Remember: for this mode you have to use VCM as the frameserver name and do not need to 'save' a signpost file.
You can now cut, join and filter content in VirtualDub and then let it frameserve directly to WM8. You cannot apply any resize or crop filters however. Use WM8's own functions to do this.
Copyright (C) 1998-2011; all
rights reserved. All
materials in these pages are presented for scientific evaluation
of video technologies only. They may not be copied from here and
used for entertainment or commercial activities of any kind.
We do not have any relation to and do not take any responsibility
for any software and links mentioned on this site. This website
does not contain any illegal software for download. If we, at
all, take up any 3rd party software here, it's with the explicit
permission of the author(s) and regarding all possible licensing
and copyright issues, as to our best knowledge. All external download
links go to the legal providers of the software concerned, as
to our best knowledge.
Any trademarks mentioned here are the property of their owners.
To our knowledge no trademark or patent infringement exists in
these documents; any such infringement would be purely unintentional.
If you have any questions or objections about materials posted
here, please e-mail us immediately.
You may use the information presented herein at your own risk
and responsibility only. We do also not guarantee the correctness
of any information on this site or others and do not encourage
or recommend any use of it.
One further remark: These pages are covering only some aspects
of PC video and are not intended to be a complete overview or
an introduction for beginners.