Entry

How do I create an MPEG-4 video

How do I convert from avi to asf

Mar 16th, 2003 20:52
Simon Ryan, http://www.virtualdub.org

In order to create an ASF file which is readable by anyone with a
standard windows box, you can do the following:
  o Install Virtual Dub [version 1.1a can read .asf files]
  o Install the old microsoft codecs
		(mptools.exe - Media Player Tools v4.0 build .3688)
		You may be able to find these using ftpsearch
  o Use Virtual Dub to create an avi with the MPEG-4 V3 codec and mp3
    audio
  o Use the following command from a DOS window
vidtoasf -in f.avi -leadtime 5000 -seekable on -optimize 1 -out f.asf
  (where f is the name of your file)
Alternatively the DiVX encoders can be used to create the AVI and then
the resulting avi can be edited with a hex editor:
	Change the 4CC in the header from DIV3 (or DIV4) to MP43
Then the resulting avi can be converted using vidtoasf as above.
Other notes:
The DivX package also contains a hacked mpeg layer 3 codec which allows
lots of bitrates. Although some of these seem to give a "conversion not
possible" error under Virtual Dub.
If you need to convert ASF, then use the older version of Virtual Dub to
load your files and then save them in AVI. You can then convert from AVI
to other formats as you normally do.
Important:
If the newer version of Media Player Tools is inadvertently installed
first, just uninstalling it and then installing the older build 3688
version is not enough. You will need to remove the file         
	c:\windows\mpg4c32.dll
after the new version is uninstalled.
The end result of this is that you can create a MPEG-4 encoded video in
a format which anyone with Windows can read. Unfortunately the ASF
container format is patented by microsoft which means that we will never
see it in real operating systems such as Linux. The alternative would
have been to leave it in AVI format, but Microsoft is attempting to
bully everyone to the new standard by "locking" out the use of MPEG-4 V3
encoding or playing with AVI. (Hence the need for their older unlocked
codecs or the DivX codecs) This brings to mind the validity of choosing
the ASF format for long term storage of video content. (Think carefully)