I try to open an mp4, a message comes that it is an Advanced Audio Coding file, and Audacity cannot open this type of file. I believe this is happening because I allowed an anti-malware program to clean my computer a bit too well. How do I reset Audacity?
Something called FFmpeg libraries has to be installed into Audacity before you can open mp4 files in it ,
[ you only get the MP4 audio in Audacity of course, not video ] … http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#[b]How_do_I_download_and_install_the_FFmpeg[/b]_Import.2FExport_Library.3F