How to Convert AIFF to MP3 Without Quality Loss

Why Convert AIFF to MP3?

AIFF (Audio Interchange File Format) is Apple's uncompressed audio format — the macOS equivalent of WAV. A typical 4-minute song in AIFF weighs 40-50 MB at CD quality (16-bit, 44.1 kHz stereo). MP3 compresses that same song to 4-8 MB at 320 kbps with quality that is transparent to most listeners in normal listening conditions.

You will encounter AIFF files from Apple Logic Pro exports, GarageBand projects, CD rips done on macOS (when the default format was not changed), professional audio production workflows that use Apple tools, and older iTunes libraries configured to import as AIFF.

Converting AIFF to MP3 makes your audio files portable across all devices and platforms while reducing storage by 80-90%. Since AIFF is uncompressed (lossless), the MP3 is being encoded from a pristine source — you get the best possible MP3 quality.

AIFF vs. MP3: Key Differences

Step-by-Step Conversion

Basic AIFF to MP3

ffmpeg -i input.aiff -c:a libmp3lame -b:a 320k output.mp3

This produces a CBR (Constant Bit Rate) 320 kbps MP3 — the highest standard MP3 quality.

Variable Bit Rate (VBR) for Optimal Quality-to-Size Ratio

VBR allocates more bits to complex passages (cymbals, orchestral swells) and fewer to simple passages (silence, single instruments), giving better quality per megabyte:

ffmpeg -i input.aiff -c:a libmp3lame -q:a 0 output.mp3

The -q:a scale runs from 0 (best, ~245 kbps average) to 9 (worst, ~65 kbps). Recommended settings:

Preserving Metadata

AIFF files can contain metadata in both AIFF chunks and ID3 tags. FFmpeg transfers standard metadata automatically:

ffmpeg -i input.aiff -c:a libmp3lame -b:a 320k \
  -id3v2_version 3 -write_id3v1 1 output.mp3

The -id3v2_version 3 flag ensures maximum compatibility with music players and the -write_id3v1 1 flag adds a legacy ID3v1 tag for older devices.

Preserving Album Art

If the AIFF contains embedded artwork:

ffmpeg -i input.aiff -c:a libmp3lame -b:a 320k \
  -c:v copy -id3v2_version 3 output.mp3

The -c:v copy flag copies the embedded image into the MP3's ID3 tag.

Batch Converting a Music Library

Convert All AIFF Files in a Directory

mkdir -p mp3
for file in *.aiff *.aif; do
  [ -f "$file" ] || continue
  ffmpeg -i "$file" -c:a libmp3lame -q:a 0 \
    -id3v2_version 3 -write_id3v1 1 \
    "mp3/${file%.*}.mp3" -y
done

Preserve Directory Structure

For organized music libraries with artist/album folders:

find /path/to/library -name "*.aiff" -o -name "*.aif" | while read file; do
  outdir="mp3/$(dirname "${file#/path/to/library/}")"
  mkdir -p "$outdir"
  ffmpeg -i "$file" -c:a libmp3lame -q:a 0 \
    -id3v2_version 3 "$outdir/$(basename "${file%.*}.mp3")" -y
done

For more on batch workflows, see our batch processing guide.

Online Conversion

Use the AIFF to MP3 converter online for quick conversions without command-line tools. Upload your AIFF file and download the MP3. For other audio formats, try the Audio Converter.

Quality and Settings Tips

320 kbps CBR vs. V0 VBR: For most listeners, V0 VBR (-q:a 0) and 320 kbps CBR are audibly identical. V0 produces 10-15% smaller files on average. The only advantage of CBR is compatibility with very old hardware MP3 players that cannot handle VBR (essentially extinct in 2026).

Sample rate conversion: AIFF files from professional audio may be at 48, 96, or even 192 kHz. MP3 supports up to 48 kHz. FFmpeg automatically downsamples if necessary. For 96/192 kHz sources, you can explicitly downsample for quality control:

ffmpeg -i input_96khz.aiff -ar 44100 \
  -c:a libmp3lame -b:a 320k output.mp3

44.1 kHz is optimal for MP3 — it is the standard sample rate for MP3 encoding, and the LAME encoder is specifically tuned for it.

24-bit to MP3: AIFF files from studio recording are often 24-bit. MP3 encoding internally converts to floating-point, so the extra bit depth is used during encoding (better dithering). No special flags needed — FFmpeg handles it automatically.

For more on audio quality settings, see our audio bitrate guide and our FLAC vs MP3 comparison.

Common Issues and Troubleshooting

"Invalid data found when processing input"

Some AIFF files use the AIFF-C (compressed) variant. FFmpeg handles most AIFF-C codecs, but rare ones (like MACE or QDesign) may fail. Convert in Apple Music or Logic Pro first as a workaround.

Metadata not appearing in player

Some music players only read ID3v2.3 tags, while others prefer ID3v2.4. Use -id3v2_version 3 for maximum compatibility. If artwork is missing, ensure you included -c:v copy in the command.

Clicks or pops at the beginning/end

Some AIFF files have non-audio data in the header that gets misinterpreted. Add -ss 0.01 to skip the first 10 milliseconds:

ffmpeg -ss 0.01 -i input.aiff -c:a libmp3lame -b:a 320k output.mp3

Output file is silent

The AIFF may use a non-standard PCM encoding (big-endian vs. little-endian). FFmpeg usually handles both, but if you get silence, explicitly specify the input format:

ffmpeg -f aiff -i input.aiff -c:a libmp3lame -b:a 320k output.mp3

Conclusion

AIFF to MP3 conversion is a clean, single-generation lossy encode from an uncompressed source — the best-case scenario for MP3 encoding. Use VBR V0 for the optimal balance of quality and file size, or 320 kbps CBR if you want a flat bitrate. Preserve metadata and artwork with the appropriate flags, and consider batch converting entire music libraries with a simple shell script.

Ready to convert? Try our free AIFF to MP3 converter — no registration required.