Convert M4P to AAC — Free Online Converter

M4P and AAC share the same underlying codec — both use Advanced Audio Coding. The difference is that M4P wraps the AAC stream inside an MPEG-4 container with Apple's FairPlay DRM (if still protected) and an .m4p extension. Converting M4P to raw AAC extracts the audio bitstream into a standalone ADTS (Audio Data Transport Stream) file, removing the MPEG-4 container entirely.

For unprotected M4P files (DRM already removed via iTunes Match or other legal means), this conversion can be performed as a lossless stream copy — FFmpeg simply strips the container and writes each AAC frame with an ADTS header. No re-encoding occurs, and the audio data remains bit-identical to the source. This is the most efficient M4P conversion possible.

Raw AAC (ADTS format) is required by streaming infrastructure like Icecast and Shoutcast servers, HLS segmenters, and broadcast multiplexing equipment. If you need to feed old iTunes audio into a streaming pipeline, extracting the AAC elementary stream is the necessary first step. The ADTS format includes per-frame sync headers that make it ideal for streaming where random access is needed.

Another motivation is escaping Apple's ecosystem labeling. Music apps and file managers treat M4P files as DRM-protected iTunes content even when the protection has been removed. Extracting to raw AAC produces a generic audio file that any AAC-capable player handles without the stigma or confusion of the M4P extension.

When the M4P is unprotected, FFmpeg performs a stream copy (-c:a copy) from the MPEG-4 container to a raw .aac file in ADTS format. Each AAC frame gets a 7-byte ADTS header containing the sync word, MPEG profile, sampling frequency index, and channel configuration. This operation is instantaneous and lossless — the AAC bitstream passes through unchanged. iTunes metadata (artist, album, artwork) and any residual DRM tags are discarded since ADTS has no metadata mechanism.