Open your MPEG file in a Media Player and check if you are able to reposition the seek-bar to any random position. If the file does not start playing from the new position then your MPEG file (or WMV/WMA file) is not seekable. If your file is seekable, then the decoder in use might not support capabilities required to edit MPEG files.

In either case, we recommend you to first make a temporary uncompressed AVI movie of your MPEG file and then edit this file. Uncompressed AVI files can take up large amounts of disk space. However, quality is not compromised and therefore they are perfect for temporary files. You may later delete the temporary file.

To convert your MPEG- II file to AVI before editing:

1.On the Tools menu, click on Media Converter.
2.In Step 1 of the Media File Conversion Wizard, specify the source (MPEG II) and the destination (AVI) file paths.
3.In Step 2, select the appropriate compressor.