MKV to AIFF Converter

MKV to AIF — and What .aif Actually Means

Short answer: .aif and .aiff are the same format under two spellings, and this page writes an uncompressed Audio Interchange File — Apple's PCM format, specified in the AIFF-1.3 document of January 1989 and read without complaint by essentially every audio application on macOS and Windows alike. The part worth understanding before you convert is that the Audio Codec you choose silently decides whether you get a classic FORM AIFF file or an FORM AIFC one, and older applications treat those two very differently. This page lays out the difference and then extracts your Matroska audio.

.aif vs .aiff vs AIFF-C: Side by Side

The .aif versus .aiff question has the least interesting answer of the three: there is no difference at all. .aif is simply the three-letter form kept from the days when file extensions could not be longer, and every application that opens one opens the other.

The practical reading of that table: leave Audio Codec on PCM 16-bit Big Endian unless something downstream specifically wants otherwise. That is the default here, it produces the classic FORM AIFF file the 1989 specification describes, and nothing will refuse it.

When to Pick AIF

• You are importing into Logic Pro, GarageBand or another Mac-centric editor, where AIFF has been a first-class format since the late 1980s.
• You want uncompressed audio and the destination is an Apple-flavoured workflow — AIFF grew up on the Mac much as WAV did on Windows.
• The recipient asked for .aif by name, which usually means an older Mac-based studio or broadcast pipeline.
• You need a format that carries no lossy compression at all, so repeated edits and exports do not accumulate generation loss.

When to Pick WAV or FLAC Instead

• You need more than 16-bit depth. This page offers 16-bit PCM only. MKV to WAV additionally offers PCM 24-bit and 32-bit Little Endian.
• The recording is very long. AIFF stores chunk sizes in a signed 32-bit field, capping a file at roughly 2 GiB — a little over three hours of 44.1 kHz 16-bit stereo. WAV's field is unsigned, so it reaches about twice that.
• You want lossless but not enormous. MKV to FLAC keeps every sample bit-exact while typically halving the size, and it carries proper tags.
• The file is going to a Windows or web workflow. MKV to WAV or MKV to MP3 will save everyone a conversation.

How to Convert MKV to AIF

1. Upload Your MKV File: Drag it onto the drop zone or click "Add Files". The video stream is discarded during extraction, so only the audio ends up in the result.
2. Leave Audio Codec on PCM 16-bit Big Endian: This is the default and it produces a classic FORM AIFF file. Change it only if a specific tool has asked for little-endian sowt or a companded A-law/mu-law variant.
3. Set Audio Channel and Audio Sample Rate: Leave Audio Sample Rate on ORIGINAL to avoid a pointless resample. Set Audio Channel to STEREO to fold a surround track down to two channels, or MONO to halve the size of a single-microphone recording.
4. Trim if Needed, Then Convert: Expand Trim, switch it off Unchanged, and enter a Start time and Duration in seconds or HH:MM:SS.sss — worth doing, because uncompressed audio grows fast. Convert and download; no sign-up, no watermark.

Which PCM Codec to Choose

Those figures are measured outputs from the same six-second source, not estimates. As a rule of thumb for planning, 16-bit stereo PCM runs about 10.6 MB per minute at 44.1 kHz and about 11.5 MB per minute at 48 kHz, whatever the byte order.

Frequently Asked Questions

Is .aif the same thing as .aiff?

Yes. They are one format with two filename spellings; .aif is the three-character form left over from the era when file extensions could not exceed three letters, and .aiff is the full name. The bytes inside are identical and every application that reads one reads the other. What does differ between files is the FORM type inside the header — AIFF for classic, AIFC for the AIFF-C variant — and that is set by the Audio Codec you choose, not by the extension you download.

Which codec produces a real AIFF rather than an AIFF-C?

PCM 16-bit Big Endian, which is the default here. We checked each option by reading the FORM type directly out of the resulting file headers: the big-endian default wrote FORM AIFF, while PCM 16-bit Little Endian wrote FORM AIFC with the sowt compression identifier, and both A-law and mu-law also wrote FORM AIFC. If a piece of older software has refused your AIFF, this is very often why — and the fix is simply to re-convert with the default codec.

What is sowt, and does it hurt quality?

sowt is "twos" spelled backwards, and despite living in AIFF-C's compression field it compresses nothing. It marks PCM whose sample bytes are stored little-endian while the header stays big-endian, which is convenient for Intel and Apple silicon machines that work in little-endian natively. Quality is bit-for-bit identical to classic AIFF and conversion between the two is lossless in both directions. The only real cost is compatibility: some older audio applications will not open a sowt file, or will play it as static.

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

Because uncompressed PCM has none. On a lossy target you would see a File Compression group with quality presets and bitrate choices; on an AIFF target that whole group is hidden, correctly, because there is no quality parameter to set. File size is determined entirely by three things you do control — sample rate, channel count and duration — plus the fixed 16-bit depth. If you want a size control, you want a compressed target such as MKV to FLAC or MKV to MP3.

Will the AIF sound better than the audio already in my MKV?

No. Extraction decodes whatever the MKV held — usually AAC, AC-3, DTS or Opus — and writes those decoded samples out uncompressed. Uncompressing a lossy source does not restore anything that was discarded when it was encoded; it just stops any further loss from occurring. That is genuinely worth having if the audio is heading into an editor for processing, but it will not make a 128 kbps AAC track sound like a master recording.

Why is the AIF so much bigger than the whole MKV's audio track?

Because you removed the compression. A film's audio might sit at 192 kbps inside the Matroska file; the same audio as 48 kHz 16-bit stereo PCM runs about 11.5 MB per minute, so a two-hour film produces roughly 1.4 GB. That is the nature of uncompressed audio and the reason AIFF and WAV are editing formats rather than distribution ones. Use the Trim controls to take only the section you need, or choose FLAC to stay lossless at roughly half the size.

My MKV has several audio tracks — which one becomes the AIF?

The one the container flags as its default. Extraction takes a single audio stream and there is no track picker in the interface, so alternate languages, director commentary and descriptive audio are all dropped. In our testing the default-flagged track was chosen even when a later track carried more channels, so do not assume the "best" track wins. If you need a specific one, re-mux the MKV with that track set as default — MKVToolNix does this without re-encoding — and upload it again.

What happens to my file after conversion?

It is uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours. Nothing is shared, published, or used for any purpose beyond producing your download. No account is required, no watermark is applied, and the file you get is the complete result.