How credits transfer is a complicated question. Here are some general answers.
General education (non-music) courses are the easiest and most likely to transfer. On the IU Admissions website you will find information about general education transfer courses. That office reviews transcripts and makes those decisions. This applies to transfer students and current IU students who take classes elsewhere. For general education courses taken at another university in the state of Indiana, you can find information at www.transferin.net.
Music academic courses fall into two categories - core curriculum in theory/history and other music. The core curriculum classes do not automatically transfer. The School of Music has a series of exams in written theory and ear training for each course. You will take an exam for each semester course we offer to determine proper placement. Those exams are traditionally offered the Thursday & Friday before the fall & spring semesters begin. More information can be found here.
See the music history transfer policy here.
Other music courses are handled by each individual department. For example, if you have taken a music education course like woodwind techniques, that department will look at the course and determine its equivalency. There are exams given by the voice department for each of the language diction courses.
Chamber music credits will transfer.
Performance courses (lessons & ensemble) do transfer but lessons & ensemble are required each semester that a student is enrolled as a music major at IU. Studio professors will determine each student's readiness for performance requirements such as recitals.
The university views class standing solely by number of credits accumulated. Time needed to finish a music degree will be determined mostly by two factors—placement in the music theory sequence and performance readiness.