Video recompressing

VirtualDUB is a freeware video editing program created by Avery Lee. Although it does not offer the possibilities of modern video editing packages, you can do some very neat things with it. One of the things is to change the compression type, framesize or bitrate. If it does not work for you, check the limitations at the bottom of this page.

1. Required Tools

• VirtualDUB. Available at our Free Downloads page.
• The codec used in the source file (in order to be able to read the file) and the codec of the target file (in order to create the new file).

2. Open the source video file

Open VirtualDUB and select File->Open Video file... Browse to the Video file and select it.

Although VirtualDUB was created to work with AVI files, the latest versions of VirtualDUB also allow you to open MPEG-1 files.

You can also process part of the file by moving the slider at the bottom of the page to the begin point and select , and moving to the end point and select .

Several files can be pasted together using File->Append AVI segment.... VirtualDUB only works with Video for Windows filters; it will therefore not work with

3. Select the codec for the target file.

Select Video->Full processing mode. Next select Video->Compression.... A window will pop up with all installed codecs on your system.

In the list click the required target codec. If the selected codec can be configured the Configure button will become selectable. Click on the Configure button and change settings as required. Other settings that you may be able to change in the above VirtualDUB window are: Quality, Bit rate (Use target data rate of) and keyframe settings (Force keyframes every).

You can also change the compression for the audio in the file in a similar way: Audio->Full processing mode and Audio->Compression....

4. Save the new file

Select File->Save as AVI. In the window that opens, browse to a folder where you want to store the new video file and give it a name.

VirtualDUB will start to process the original file and create the new one.

This may take some time. You can speed up the process by giving it a higher priority on your processor by changing Processing thread priority.

5. Limitations

VirtualDUB opens video files using Video for Windows filters and therefore it cannot open a Type-1 AVI file through the standard Microsoft DV codec. If you want to open a DV-AVI file, you can do one of the following things:

• Install a third party DV codec. Some examples are the Panasonic VFW DV codec and the Canopus DV Codec (free, from our download page).
• Change the file from Type-1 to Type-2. Some conversion tools are Canopus DV File converter, or the DV Type-1 to Type-2 Converter form Ulead (free, form our download page).

You can not use VirtualDUB to encode movies, so you cannot create MPEG-files using VirtualDUB.