VirtualDUB frameserver

This manual will help you understand, install and use the VirtualDub frame server. Actually it is very easy and can be very helpful for some situations. The frame-server can be used to preprocess an AVI file before encoding, without creating an intermediate AVI file. The frame-server will be seen by the client application (the MPEG encoder for example) as an uncompressed AVI file.

Understand frameserving
Required software & installation
Start frameserving
Stop frameserving
Frameserve TMPG-Encoder to preprocess video
Using the frameserver: a bunch of (S)VCD preprocessors
Help to face most situations

1. Understand frameserving

Frameserving means that an application, the server, will create a video file, frame by frame and make the resulting audio and video streams available for another application, the client application. The client will pick up the video frame by frame from the server (it uses Windows inter-process communication featured, known as IPC). The audio stream is transferred verbatim, although clipping and offset options are functional.

The main use of VirtualDub frameserver is to preprocess video for MPEG encoders.

Also, preprocessing is commonly used to resize to (S)VCD format, to deinterlace video, to smooth or denoise video, to correct picture levels (histogram) and to resample audio.

Another common usage is to workaround a codec/client bug. The most common is for DivX files, because DivX codecs are still in Alpha or Beta release, with some bugs. Some applications (like TMPG-Encoder) will be stuck reading a DivX file or will produce black frames. The idea here is just to open the DivX file into VirtualDub and to frameserve for TMPG-Encoder which will see the DivX file as an uncompressed AVI file. Please note that AVIsynth frameserving is also a good solution for such a case.

2. Required software & installation

Required software is included in the VirtualDub package:

Start AuxSetup and click on Install handler.
Open the VirtualDub aviproxy folder and double-click on the proxyon.reg file to install the AVI proxy.

AVI proxy mode is an experimental feature added by Avery Lee to make most applications work as a client. Instead of saving the virtual AVI file with .vdr extension, you can save it with the .avi extension so most video applications will succeed in opening it.

For some client applications (Xing MPEG Encoder 2.20) the proxy must be turned off by double clicking proxyoff.reg.

Frameserver support works fine with Windows 95, 98 and Windows 2000 Professional.

3. Start frameserving

Instead of doing Save as AVI... , just choose Start frame server... in the File menu, and then confirm the file name by pressing the Start button:

Then choose a name for the server file, it will be used by the client application which will have to open a video file. The default extension is .vdr but you can also set it to an .avi extension to workaround some situations (for more details see the help table below).

When you press the Save button (Enregistrer, in my example on a French Windows 2000 Profressional), the frameserver starts, opening this popup window (the main VirtualDub windows disappears):

Now, the framserver is running and you can access the video, it's as easy as opening the server .vdr file in a client application (see the TMPG example below).

4.Stop frameserving

The popup window must stay open the whole time the client application needs the video.

When you want to stop frameserving, just press the Stop serving button in the popup window (the main VirtualDub windows comes back).

5. Frameserve TMPG-Encoder to preprocess video

Assuming you did all the stages (from 1 to 3) and you have the popup window opened, start the TMG encoder application.

Then Browse to open the .vdr file and the picture will appear, exactly like opening an AVI file. Now you can use TMPG as usual.

6. Using the frameserver: a bunch of (S)VCD preprocessors

The main use of VirtualDub frameserver is to process video before encoding to MPEG for VCD or SVCD. Here are some of the most used filters to get a better (S)VCD picture (less blocky, color correction and so on). These preprocessors have been designed for Full D1 (720x480 or 720x576) video input but should work fine for most input sizes.

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