MP3 to AAC Converter Convert MP3 audio files to AAC format in your browser.

The conversion uses the Web Audio API to decode the MP3 source file into PCM audio buffers via AudioContext.decodeAudioData(). The decoded audio is then processed through an OfflineAudioContext to normalize the sample data. For AAC encoding, the tool uses the MediaRecorder API with the audio/mp4;codecs=mp4a.40.2 MIME type (AAC-LC profile), which is natively supported in most modern browsers. The audio stream is captured from a MediaStreamDestination node and recorded into an M4A/AAC container. The resulting file maintains the original sample rate and channel count while benefiting from AAC's more efficient compression algorithm, which typically achieves transparency at lower bitrates than MP3.