？
Is it true that iTunes' MP3 encoder has bad sound quality?
Literal
iTunes [genitive-の] MP3 encoder [topic-は] sound-quality [subject-が] bad [hearsay-って] true?
A casual tech question. 音質が悪い ('sound quality is bad') uses が with the adjective 悪い to describe an attribute. って is the casual quotative — 'I heard that / they say that.' 本当？ ('really? / is it true?') is the follow-up seeking confirmation. Full-width ＭＰ３ is typical of Japanese tech forums. The sentence captures the casual, peer-to-peer register of online tech discussion.