AIFF to AAC Converter

AIFF to AAC — Convert an Uncompressed Master to a Compact AAC Stream

AIFF is Apple's uncompressed studio format — a full PCM waveform that runs roughly 10 MB per minute for CD-quality stereo. This tool re-encodes that audio to AAC and writes it as a raw .aac file (an ADTS stream), so the size drops dramatically. Two things to know before you start: this is a lossless-to-lossy step, so detail the encoder discards never comes back — keep the AIFF as your master; and the output is a bare .aac stream, not an .m4a, so it carries no tags or artwork and some players (such as QuickTime) won't open it. Pick .aac when a tool, encoder, or streaming pipeline wants raw AAC frames; for everyday listening use AIFF to M4A instead.

Raw .aac vs .m4a — Which Output Do You Want?

Both carry the same AAC codec; the difference is the wrapper. A raw .aac is an ADTS stream of self-synchronizing frames with nowhere to store metadata, while an .m4a wraps the same AAC audio inside an MP4 container that holds tags, artwork, and a seek index.

If you just want a small, taggable file to play on a phone or in iTunes, use AIFF to M4A — same AAC codec, but a tagged, broadly compatible file. If you want a smaller file with no quality loss at all, convert to a lossless format like FLAC instead.

Picking an AAC Bitrate

AIFF is lossless, so the bitrate you choose sets how much of that fidelity survives the re-encode. Higher bitrates sound closer to the master but shrink the file less.

When to Pick Raw .aac

• A downstream encoder, muxer, or streaming pipeline expects raw AAC frames rather than an MP4-wrapped file.
• You are feeding the audio into a tool that reads ADTS directly and tags do not matter.
• You want the leanest possible AAC payload with no container overhead.
• You will re-wrap or re-mux the stream yourself later.

When to Pick .m4a Instead

• You want to play the file on an iPhone, iPad, or in iTunes without compatibility surprises.
• You need the result to carry title, artist, album, or cover art.
• You are building a music library where reliable seeking and tagging matter.
• A player such as QuickTime keeps refusing the raw .aac file.

How to Convert AIFF to AAC

1. Upload Your AIFF File: Drag and drop your .aiff or .aif file onto the page, or click "+ Add Files" to browse. You can queue several at once and convert them with the same settings.
2. Set the Bitrate under File Compression: File Compression opens on Quality Preset, the hands-off mode — and the least predictable control here, with nothing actually pre-selected in its dropdown. Open Advanced Options and choose Constant Bitrate instead (the dropdown runs from 8 kbps to 384 kbps and opens on 128 kbps; 256 kbps suits a lossless AIFF source), Custom Bitrate for an exact figure, or Variable Bitrate and one of its five AAC bands to trade size against fidelity.
3. Adjust Audio Channel, Sample Rate, or Trim (Optional): Keep Audio Channel and Audio Sample Rate on "Original" to match the source, downmix to mono to shrink a voice recording, or use Trim to keep only part of the audio.
4. Convert and Download: Click "Convert" and save your .aac file. No sign-up, no watermark.

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — never shared or made public.

Frequently Asked Questions

Will I lose quality converting AIFF to AAC?

Yes, by design. AIFF is uncompressed PCM and AAC is a lossy format, so the encoder permanently discards audio detail to shrink the file. At higher bitrates the result is transparent to most listeners on typical playback gear, but the discarded data cannot be recovered. Always keep the original AIFF if it is your only master — re-encode future conversions from that lossless source, not from an AAC copy.

What's the difference between this .aac file and an .m4a?

Both hold AAC audio; the container differs. This tool outputs a raw AAC stream in ADTS framing with a .aac extension — a series of self-synchronizing frames with no place to store tags. An .m4a wraps the same AAC audio in an MP4 container that holds metadata and a seek index. Pick .aac when a downstream tool or stream wants raw AAC frames; pick M4A for everyday playback and tagging.

Why won't my raw .aac file open in some players?

A raw ADTS .aac is not an MP4, so players that expect a container can reject it — QuickTime, for example, will not open raw AAC ADTS files. Most general-purpose players (VLC, modern browsers) and audio tools read it fine, but if a specific app refuses the file, convert to M4A or MP3 instead, which use the broadly supported MP4 and MPEG containers.

Does the .aac file keep my track titles or artwork?

No. ADTS framing has no field for tags, so title, artist, album, and cover art are not written to a raw .aac file. AIFF masters often carry little embedded tag data to begin with, but anything that is there will not transfer. If you need embedded metadata, choose M4A, whose MP4 container stores tags, or add tags afterward in your own library tool.

What bitrate should I choose for AIFF to AAC?

For music, a higher constant bitrate such as 256 kbps is a common choice that most listeners cannot distinguish from the source. For spoken-word content like podcasts or audiobooks, lower bitrates around 96–128 kbps keep files small with no meaningful loss. In our testing, a 4-minute 44.1 kHz stereo AIFF re-encoded to a 256 kbps AAC stream produced an .aac file roughly a tenth the size of the original — the exact ratio depends on the source and the bitrate you pick.

Why is my AIFF file so much larger than the AAC?

Because AIFF is uncompressed: it stores the full PCM waveform at about 10 MB per minute for CD-quality stereo. AAC applies lossy compression, removing data the ear is unlikely to notice, so the same audio fits into a fraction of the space. That size reduction is the whole reason to run the conversion.

Should I use constant or variable bitrate for the AAC?

Constant bitrate (CBR) spends the same number of bits every second, so the file size is predictable and player compatibility is at its widest — pick a rate like 256 kbps and the whole track uses it. Variable bitrate (VBR) lets the encoder spend more bits on complex passages and fewer on simple ones, which is often a little more efficient at the same perceived quality, though the final size is harder to predict. For a raw .aac stream headed into another tool, CBR is the safer choice; both Constant and Variable Bitrate are available under Advanced Options.

Can I upload .aif files, not just .aiff?

Yes. AIF and AIFF are the same format — AIF is just the three-letter extension used on systems that prefer short names. Upload either and the converter treats them identically.