Convert WMA to AAC — Free Online Converter

WMA (Windows Media Audio) is Microsoft's proprietary codec that competed with MP3 throughout the 2000s, offering competitive quality in the Windows ecosystem. AAC (Advanced Audio Coding) is the industry-standard lossy codec adopted by Apple, YouTube, and every major streaming platform. AAC is technically superior to both WMA and MP3, delivering better audio quality at equivalent bitrates.

Converting WMA to AAC moves your audio from Microsoft's proprietary format to the universally adopted standard. AAC plays natively on iOS, macOS, Android, Windows, and in all modern web browsers, making it the most compatible lossy audio format available.

WMA's relevance has steadily declined since the end of the Zune era and Windows Phone. While Windows still supports WMA, macOS, iOS, and most mobile platforms do not play WMA natively without third-party apps. AAC, by contrast, is the native audio codec for Apple's entire ecosystem and is supported by every modern device and browser.

AAC also delivers measurably better quality than WMA Standard at equivalent bitrates. At 128 kbps, AAC produces fewer audible artifacts than WMA. Migrating a WMA library to AAC future-proofs your audio collection while improving cross-platform compatibility.

FFmpeg decodes the WMA stream (wmav1/wmav2 using the ASF demuxer) to PCM, then re-encodes using the AAC encoder. The output is wrapped in an M4A container (MPEG-4 Part 14) for maximum compatibility. Since both are lossy codecs, this is a transcode with cumulative quality loss — the AAC output cannot exceed the WMA source quality. The encoder applies MDCT and psychoacoustic modeling appropriate for the target bitrate. HE-AAC and HE-AACv2 profiles are available for low-bitrate scenarios.