AIF vs SPX
A detailed comparison of AIFF Audio (short) and Speex Audio — file size, quality, compatibility, and which format to choose for your workflow.
AIFF Audio (short)
Audio FilesAIF is the short file extension for AIFF (Audio Interchange File Format), an uncompressed audio standard developed by Apple based on the IFF structure. It provides CD-quality lossless audio and is widely used in professional music production on macOS.
About AIF filesSpeex Audio
Audio FilesSpeex is an open-source audio compression format specifically designed for speech encoding. It uses Code-Excited Linear Prediction (CELP) and supports narrowband, wideband, and ultra-wideband modes for different speech quality requirements.
About SPX filesStrengths Comparison
AIF Strengths
- Lossless and uncompressed — bit-exact audio.
- Universal Mac compatibility.
- Compatible with every pro audio editor.
- 3-character extension for legacy Windows.
SPX Strengths
- Patent-free voice codec.
- Three sample-rate modes for voice.
- Low CPU decode.
Limitations
AIF Limitations
- Large files — no compression.
- Same limitations as .aiff.
- Redundant extension in modern workflows.
SPX Limitations
- Deprecated in favor of Opus.
- No music support.
- Rarely used in new projects.
Technical Specifications
| Specification | AIF | SPX |
|---|---|---|
| MIME type | audio/aiff | audio/speex |
| Extension | .aif | .spx |
| Container | IFF (big-endian PCM) | Ogg |
| Alias of | .aiff | — |
| Variants | .aifc (AIFF-Compressed) | — |
| Modes | — | Narrowband/Wideband/Ultra-wideband |
| Successor | — | Opus |
Typical File Sizes
AIF
- 3-min song (CD quality) 30 MB
- 3-min song (24-bit / 96 kHz) 100 MB
SPX
- 1 min voice (wideband 24 kbps) ~180 KB
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Frequently Asked Questions
AIF (AIFF Audio (short)) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
SPX (Speex Audio) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
VLC, foobar2000, and the default media players on Windows and macOS handle AIF natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
VLC, foobar2000, and the default media players on Windows and macOS handle SPX natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
Upload the AIF to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
AIF can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.