Does converting AAC to AIFF improve audio quality?

No. AAC is a lossy format — audio data was discarded when the AAC file was originally encoded. Converting to AIFF produces an uncompressed copy of that already-decoded audio. The AIFF will sound identical to the AAC; it will simply be larger and compatible with tools that require uncompressed PCM input. For higher quality, obtain a lossless source (FLAC, WAV, or AIFF) from the start.

What is the basic FFmpeg command for AAC to AIFF?

ffmpeg -i input.aac output.aiff. By default FFmpeg outputs 16-bit PCM (pcm_s16be — AIFF uses big-endian byte order). For 24-bit: ffmpeg -i input.aac -c:a pcm_s24be output.aiff. For M4A files the same commands apply — just change the input extension.

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

AAC uses lossy compression that typically reduces file size by 10x or more compared to uncompressed PCM. A 5 MB AAC file might become a 50 MB AIFF. This is expected — AIFF stores every audio sample as raw integers with no compression. Use ALAC (Apple Lossless) if you need a compressed lossless format native to Apple tools.

What is the difference between AIFF and WAV?

Both AIFF and WAV store uncompressed PCM audio and produce identical sound quality. The main differences are: AIFF uses big-endian byte order and is the native Apple format (preferred by Logic Pro, GarageBand, Final Cut Pro), while WAV uses little-endian byte order and is the Windows standard. On macOS either format works, but AIFF is often the default export target for Apple software.

Which bit depth should I choose for AIFF?

16-bit PCM is the standard for CD audio and offers the widest compatibility with media players, DAWs, and devices. 24-bit is preferred for studio recordings and mastering, and is the default for most professional Apple workflows. AIFF supports up to 32-bit integer but 24-bit is the practical maximum for most use cases.

How do I batch-convert AAC files to AIFF on macOS or Linux?

Run: for f in *.aac; do ffmpeg -i "$f" "${f%.aac}.aiff"; done. For M4A files: for f in *.m4a; do ffmpeg -i "$f" "${f%.m4a}.aiff"; done. Add -c:a pcm_s24be before the output file name to choose 24-bit output.

AAC to AIFF Converter

Name: AAC to AIFF Converter
Availability: InStock
Author: Nham Vu

Generate the exact FFmpeg command to convert AAC audio to lossless AIFF at any bit depth, and estimate the output file size before you run it.

File Details

Enter your file name and duration to generate the FFmpeg command and estimate the output AIFF size.

Input File Name

Also accepts .m4a, .mp4, or any AAC-containing file.

Duration

hrs

min

sec

FFmpeg Command Generator

Output AIFF Bit Depth

Copy metadata tags from source (-map_metadata 0)

ffmpeg -i "input.aac" -c:a pcm_s16be -map_metadata 0 "input.aiff"

Install FFmpeg free at ffmpeg.org. Run this command in your terminal after replacing the file name.

Batch convert AAC files (macOS / Linux)

for f in *.aac; do ffmpeg -i "$f" -c:a pcm_s16be -map_metadata 0 "${f%.aac}.aiff"; done

Batch convert M4A files (macOS / Linux)

for f in *.m4a; do ffmpeg -i "$f" -c:a pcm_s16be -map_metadata 0 "${f%.m4a}.aiff"; done

GUI alternatives

Audacity — free; open an AAC file and export as AIFF (requires FFmpeg library for AAC import)
VLC — free media player; use Media → Convert, select AIFF as output format
iTunes / Music (macOS) — File → Convert → Create AIFF Version (requires AAC to be DRM-free)
fre:ac — free, open-source batch converter; Windows, macOS, and Linux

Output AIFF File Size Estimator

Based on the duration you entered, assuming stereo 44.1 kHz. Formula: sample_rate × channels × (bit_depth / 8) × duration + 54 (54-byte AIFF header).

16-bit PCM

—

24-bit PCM

—

32-bit PCM

—

Duration: 3 min 30 sec (210 s)

How FFmpeg Converts AAC to AIFF

FFmpeg handles the complete pipeline on your local machine — no upload required:

1 FFmpeg opens the AAC or M4A container and reads the compressed audio stream.
2 The built-in AAC decoder converts the compressed stream to raw PCM samples in memory.
3 FFmpeg re-orders the bytes to big-endian (AIFF standard) and packs them into an AIFF container with an IFF/COMM header.
4 The output .aiff file is written to disk — ready for Logic Pro, GarageBand, Final Cut Pro, or any DAW.

Install FFmpeg at ffmpeg.org (free, open-source). macOS: brew install ffmpeg. Linux: sudo apt install ffmpeg.

AIFF Bit Depth Reference

Bit Depth	FFmpeg Codec	Size / min (stereo 44.1 kHz)	Typical Use
16-bit PCM	pcm_s16be	~10.1 MB	CD audio, iTunes/Music, general use
24-bit PCM	pcm_s24be	~15.2 MB	Logic Pro, mastering, broadcast
32-bit PCM	pcm_s32be	~20.2 MB	Archive, specialized precision workflows

AAC vs. AIFF — At a Glance

AAC (Advanced Audio Coding)

Efficient lossy compression (small file size)
Default format for Apple Music, YouTube, and mobile streaming
Lossy — audio data discarded permanently
Not accepted by all professional DAW workflows

AIFF (Audio Interchange File Format)

Uncompressed PCM — native Apple format for Logic Pro and GarageBand
Supports embedded metadata (ID3 tags, markers, loops)
Large file size (10x or more vs. compressed AAC)
Big-endian byte order — less common on Windows than WAV

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Summary

Generate the exact FFmpeg command to convert AAC audio to lossless AIFF at any bit depth, and estimate the output file size before you run it.

How it works

Enter your AAC file name and its duration in the form below.
Choose a target AIFF bit depth — 16-bit for CD compatibility, 24-bit for studio use.
Copy the generated FFmpeg command.
Open a terminal, paste the command, and run it. FFmpeg decodes the AAC stream and writes uncompressed PCM to an AIFF container.
Play the output AIFF to verify it before deleting your original AAC file.

Use cases

Import AAC audio into Logic Pro, GarageBand, or Final Cut Pro, which prefer AIFF over WAV on macOS.
Convert Apple Music or iTunes AAC downloads to AIFF for professional audio workflows.
Prepare AAC audio tracks for CD mastering or broadcast delivery requiring uncompressed PCM.
Extract audio from M4A or MP4 containers and save as AIFF for further editing.
Batch-convert an entire AAC library to AIFF using a shell loop.
Estimate the AIFF output file size before committing to a large batch conversion.
Generate a ready-to-paste FFmpeg command without memorizing its flags.
Convert spoken-word AAC files to AIFF for compatibility with macOS transcription tools.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu