ASF files are a proprietary file type created by Microsoft. It is a file format that includes both video and audio encoding. MP3, meanwhile, is an audio-only format. You can, however, convert an ASF file into an MP3 file with a web-based application. This process can be done on a Mac, but it also can be done on other operating systems.
Go to http://media-convert.com/zh/. This is a website that converts many different file types. It is compatible with all operating systems, including the Mac operating system, as long as you are connected to the Internet.
Import the ASF file you would like to convert by clicking the "Browse" button located at the top of the page. You will be able to find the file from this interface.
Select your input format. A drop-down menu displaying all of the possible file types is located directly to the right of the input text box. Normally, the website will automatically recognize the file type and automatically populate this field, but if it does not, you can choose ASF manually.
Select your output format from the output format drop-down menu. Select MP3 for this conversion. Convert-direct allows you to convert video to audio files, and therefore, an ASF can be converted into an MP3.
Populate any advanced settings if you would like. Advanced settings include tagging the file for data like title, artist, album and year of production. This step is optional.
Click the "OK" button located directly to the right of the output format drop-down menu. The conversion process will occur and you will see a "File upload progression" indicator. This process may take several minutes.
Download the converted file. After the conversion is completed, a link will appear that contains the converted file. Click the link and download the converted file.