Vidtoasf.exe Increases File Size When Converting AVI Files

• Microsoft Windows Media Services version 4.0
• Microsoft Windows NT Server NetShow Services version 3.0

SYMPTOMS

When you convert a low frame rate .avi file into a .asf file with the command line utility Vidtoasf.exe, the file size of the .asf file increases dramatically.

CAUSE

With low frame rate files, the first frame of the file is usually very large. This large frame must be sent within one second (the default) to the client. In order for this to be accomplished, the bit rate of the file is raised and filler is added to the file. The filler is what raises the bit rate and increases the file size.

RESOLUTION

When you use Vidtoasf.exe with low frame rate files, increase the lead time parameter from 1000 milliseconds (default) to a larger number. (Note: You probably won't see any benefit above 4000 milliseconds.) By increasing the lead time for the file, there is more time available to stream the first frame of the video when the file is streamed to a client. An example of this would be as follows:

vidtoasf.exe -in myfile.avi -out myfile.asf -leadtime 3000 

Additional query words: netshow wms

Keywords :
Version : :4.0; winnt:3.0
Platform : winnt
Issue type : kbprb