It IS a violation of copyright.
Some people do it all the time, however.
There is lots of buyout music available that sounds good, and can be used instead of copyrighted works. You can get permission to use copyrighted songs. It can be a difficult process, and can be VERY expensive for highly popular pieces. Some people do it all the time, however. There is lots of buyout music available that sounds good, and can be used instead of copyrighted works.