video encoding&cleaning

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.

Using VirtualDub with WM8

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.


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