The largely involves a basic video "demux" function of the original .wmv file, but the process also involves the insertion of VC-1 compliant "Sequence" and "Entry Point" headers at specific points in the output bitstream. The information required is gathered from a variety of places within the original  .wmv file, the headers are constructed, and the output file, which consists of an appropriately interleaved combination of these headers and the demuxed video content, is written to the output file. The utility optionally displays a relatively large amount of technical data concerning the details of the operation as the conversion it takes place.

See the ASF2VC1_Readme.txt (also included in the download ZIP) for more details.

• Coded directly to comply with SMPTE 421M-2006, the VC-1 specification document.
• Able to create byte for byte matching output against nine widely varying reference files created my Microsoft's own "in-house" converter.
• The aforementioned test files, as well as many others, were also tested. Testing was achieved by performing the conversion and using the resulting VC-1 output file as input to the SMPTE 421M reference decoder (the standard test for VC-1 compliancy). No errors or warnings ensued.

Download ASF2VC1v1.2.zip  60KB
(.exe plus readme & license)