MP4 to AIFF Converter

Extract AIFF Audio from MP4: What This Tutorial Covers

This walk-through pulls the audio track out of an MP4 video and writes it as AIFF (.aif) — uncompressed linear PCM, the format Logic Pro, GarageBand, Pro Tools and the macOS Music app read natively. There is no video in the output; you get the soundtrack as a standalone audio file. It also covers the part most converters skip: AIFF has no bitrate or quality dial at all, so the only levers you have over the file size are the sample rate, the channel count, and how much of the track you keep.

How to Convert MP4 to AIFF

1. Upload Your MP4 File: Drag and drop, or click "Add Files" to pick an MP4 (.mp4 or .m4v) from your computer. Several files can be queued and converted with the same settings. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours.
2. Pick an Audio Codec: Open Advanced Options. Audio Codec is set to PCM 16-bit Big Endian by default — that is standard AIFF. The three alternatives (PCM 16-bit Little Endian, PCM A-law, PCM mu-law) all write an AIFF-C file instead; see the table below before switching.
3. Set Audio Sample Rate and Audio Channel: Both start on ORIGINAL, which copies the MP4's own values. Choose 44100 Hz for CD-style delivery or 48000 Hz to match a video timeline; choose MONO to halve the file when the source was recorded mono.
4. Trim and Convert: Switch Trim from Unchanged to enter a Start time and Duration (in seconds or HH:MM:SS.sss) if you only need a section, then click Convert and download the .aif. No sign-up, no watermark.

Walk-through: Which of the Four Codecs to Pick

This page shows exactly four entries under Audio Codec, and there is no bit-depth menu, no bitrate box and no quality preset anywhere on it — that is correct behaviour for an uncompressed target, not a missing feature. What the codec choice really decides is which flavour of the container gets written.

• Leave it on PCM 16-bit Big Endian unless you have a specific reason not to. Big-endian 16-bit is the original AIFF encoding, and the file header comes out as a classic FORM…AIFF. Every AIFF-aware application on macOS and Windows opens it.
• PCM 16-bit Little Endian is Apple's sowt variant — byte-swapped samples with no compression at all. It is bit-for-bit the same audio, but because sowt is an AIFF-C compression type, the header becomes FORM…AIFC. Pick it only if a specific tool asked for it.
• PCM A-law and PCM mu-law are the G.711 telephony codecs. They squeeze each sample into 8 companded bits, which halves the data rate but throws audio away — these are the only lossy choices on the page, and they also produce an AIFF-C file.
• There is no 24-bit option here. If you need higher bit depth for a mastering chain, MP4 to WAV exposes 24-bit and 32-bit PCM; an MP4's AAC track is 16-bit-equivalent anyway, so 24-bit gains you headroom for later processing, not extra source detail.

How Big the AIFF Will Be

Uncompressed PCM has a fixed data rate, so the output size is pure arithmetic — it does not depend on how loud or complex the audio is. We derive these from the format rather than from a benchmark: 44,100 samples per second × 2 bytes per sample × 2 channels = 176,400 bytes per second.

Because AIFF stores its chunk lengths in 32-bit fields, a single file cannot grow past roughly 2 GB — about three and a half hours at 44.1 kHz 16-bit stereo. For anything longer, split the source first with the Video Cutter or use a format without that ceiling, such as FLAC.

Common Errors and How to Fix Them

• "The AIFF doesn't sound any better than the MP4." It won't. MP4 audio is almost always AAC, which is lossy. The converter decodes that AAC and stores the result as uncompressed PCM — it preserves what survived the original encode but cannot rebuild detail AAC already discarded. The win is workflow (no re-decode inside your DAW, no further generation loss), not fidelity.
• "The output file is enormous." Expected. A 128 kbps AAC track is about 0.96 MB per minute; the same audio as 44.1 kHz stereo AIFF is about 10.6 MB per minute — roughly eleven times larger. Set Audio Channel to MONO for voice sources, drop the Audio Sample Rate, or Trim to the part you need.
• "I got an .aifc-style file instead of plain AIFF." You changed Audio Codec away from PCM 16-bit Big Endian. Little-endian, A-law and mu-law all require the AIFF-C extension, so the header changes even though the extension you downloaded is still .aif. Switch back to PCM 16-bit Big Endian for the classic form.
• "Windows won't open the .aif." Windows has patchy first-party AIFF handling depending on which media app is installed. VLC, foobar2000 and Audacity all open AIFF reliably; alternatively convert to WAV, which is the native uncompressed format on Windows.
• "The upload is slow." The practical limit on a big source is upload size and time. Trim the clip first, or extract from a smaller copy of the video — the audio track is identical regardless of the video resolution.

When This Doesn't Work

DRM-protected MP4s (purchased or rented titles) cannot be decoded, and the conversion will fail rather than produce a silent file — that protection is the whole point of the DRM. A truncated or partially downloaded MP4 can also error out because the audio index is incomplete; re-download and retry. And if the MP4 genuinely has no audio track — common with screen recordings and some drone footage — there is nothing to extract. If your goal is a small, shareable file rather than an uncompressed master, AIFF is the wrong target: use MP4 to MP3 for distribution, or MP4 to FLAC for lossless audio at roughly half the AIFF size.

Frequently Asked Questions

Will extracting to AIFF give me better audio than the MP4 had?

No. AIFF is an uncompressed container, not a quality restorer. MP4 audio is normally AAC, so the AIFF holds the AAC-decoded samples as PCM — the same audible quality in a much larger file. AIFF only carries genuinely lossless quality when the source MP4 already held PCM, which is rare. What you reliably gain is a file your DAW reads without decoding AAC on every playback pass, and no additional generation loss as you edit.

Why is the .aif so much bigger than my MP4?

Because AAC compresses and AIFF does not. At 44.1 kHz, 16-bit, stereo, AIFF runs at a fixed 1,411 kbps — about 10.6 MB per minute — while the AAC track inside the MP4 might have been 128-256 kbps. The video you discarded doesn't offset that; the audio alone expands roughly five to eleven times. Lower the Audio Sample Rate, switch to MONO if the source was mono, or Trim to the section you actually need.

Is .aif the same as .aiff, and when do I get an AIFF-C file?

.aif and .aiff are the same format — Audio Interchange File Format, which Apple published in 1988 on top of Electronic Arts' IFF container; the extension length is the only difference. AIFF-C, released in July 1991, extends the container to carry compression types. On this page you get plain AIFF with the default PCM 16-bit Big Endian codec, and an AIFF-C file if you switch to little-endian (sowt), A-law or mu-law, because all three are registered as AIFF-C compression types.

What sample rate, bit depth and codec does the output use if I change nothing?

Audio Sample Rate and Audio Channel both sit on ORIGINAL, so the output copies the MP4's own rate (usually 44.1 kHz or 48 kHz) and channel layout. Audio Codec is set to PCM 16-bit Big Endian, so the bit depth is 16 and the byte order is big-endian. Those defaults are what Logic, Pro Tools and GarageBand expect from an AIFF, and they are the only combination on this page that produces a plain FORM…AIFF header.

Why are there no bitrate or quality settings on this page?

Because AIFF is uncompressed — there is no quality knob to expose. Every sample is stored at full width, so the file size is determined entirely by sample rate × bit depth × channels × duration. On lossy targets the same converter shows Quality Preset, Constant Bitrate and file-size controls; here they are hidden because none of them would do anything. If you want to choose a bitrate, extract to M4A or MP3 instead.

Can I pull out just one section instead of the whole track?

Yes. Switch Trim from Unchanged and enter a Start time and Duration, either in plain seconds or as HH:MM:SS.sss. Only that segment is written to the AIFF, which cuts both the conversion time and the file size. For multi-region edits, extract the full track first and then use Trim AIFF on the result — the general Audio Cutter works on audio files, not on the source video.

Should I extract to AIFF or to WAV?

They store identical uncompressed PCM; the difference is convention and metadata. AIFF is big-endian, originated on the Mac, and carries its metadata in named IFF chunks that Apple software reads cleanly. WAV is little-endian, is the default on Windows, and is what most sample libraries and game engines expect. If your project lives in Logic, GarageBand or the Music app, take AIFF; if it lives in a Windows DAW or you need 24-bit, take WAV.

Is there a length limit on an AIFF file?

Effectively yes. AIFF inherits IFF's 32-bit chunk-size fields, so a file tops out near 2 GB — about three and a half hours of 44.1 kHz 16-bit stereo, or seven hours in mono. Long recordings such as full concert videos or day-long lectures will hit that wall before anything else does. Trim the source into parts, drop to mono, or convert to FLAC, which stays lossless while roughly halving the size.

What happens to my video after the conversion?

It is uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no account, no watermark, and nothing is shared or made public. The conversion itself always re-encodes the audio into PCM rather than copying the AAC stream through, which is why the output is a true AIFF rather than a renamed MP4.