MPEG-4 Audio (M4A) stores AAC-encoded audio in an MPEG-4 container, the standard audio format produced by iTunes and Apple devices. Free Lossless Audio Codec (FLAC) applies lossless compression to PCM audio, preserving the original waveform exactly while reducing file size by 40-60% versus WAV. This conversion changes the file's encoding, compression method, and supported feature set. Metadata such as creation date and embedded colour profiles is preserved where the target format supports it. The result is a standard FLAC file readable by any compatible application. 1converter handles M4A-to-FLAC conversion server-side: files are uploaded over HTTPS, processed on isolated cloud infrastructure, and the converted output is available for download for 24 hours before automatic deletion. No account is required for standard conversions.