Free tool
AAC to text converter
Drop an .aac file here to change AAC to text: the converter decodes the AAC sound in your browser and writes a transcript with a time on every paragraph, which you can copy or download.
- Free
- Raw .aac files too
- Nothing is stored
Drop your AAC file here, or Choose your AAC file
MP3, M4A, WAV, AAC, FLAC, OGG or WebM. Up to 30 minutes of each file, 3 free files a day. The language is detected automatically.
Transcribing AAC recordings often? NoteOwl does it on your Mac with unlimited transcription, labels each speaker and keeps every transcript searchable.
How it works
How do you transcribe an AAC file?
Choose the .aac file, or drag it onto the converter. The page reads its AAC frames, decodes them, and splits the sound at pauses into short pieces that AI transcription turns into text. Then copy the transcript or download it.
- 1
Add the AAC file
A raw .aac file, or the M4A, MP4 or MOV it came from: the converter reads all of them.
- 2
Watch the text arrive
Each paragraph shows where it starts in the recording. The first 30 minutes of every file are transcribed.
- 3
Save the transcript
Copy it, or download TXT, SRT, VTT or Word, named after the AAC file.
What is an AAC file?
AAC (Advanced Audio Coding) is a compressed sound format, the successor to MP3 and the sound inside most M4A, MP4 and MOV files. A file ending in .aac holds that sound on its own, frame after frame, with no container around it.
Raw AAC files come from recorder and call-recording apps that offer AAC as a format, from saved internet radio streams, and from tools that copy a video’s sound out without re-encoding it.
- .aac
- How the AAC is keptBare frames, each with a short header (ADTS)
- Typical sourceRecorder apps, radio stream recordings, sound copied out of a video
- .m4a
- How the AAC is keptInside an MPEG-4 audio file
- Typical sourceVoice Memos, Zoom’s audio-only file, Android recorders
- .mp4 and .mov
- How the AAC is keptNext to the picture in a video
- Typical sourcePhone cameras, screen recordings, video calls
| File | How the AAC is kept | Typical source |
|---|---|---|
| .aac | Bare frames, each with a short header (ADTS) | Recorder apps, radio stream recordings, sound copied out of a video |
| .m4a | Inside an MPEG-4 audio file | Voice Memos, Zoom’s audio-only file, Android recorders |
| .mp4 and .mov | Next to the picture in a video | Phone cameras, screen recordings, video calls |
Is AAC the same as M4A?
Not quite. AAC is the sound; M4A is one kind of file built around it. An .aac file has the same sound without that wrapper, and without the index an M4A keeps. The converter reads both, so there’s nothing to change first.
With no index, some players can’t tell how long an .aac file is. The converter counts its frames instead, so the length it shows above the transcript is the real one.
Do HE-AAC and low-bitrate AAC files work?
Yes. Ordinary AAC (AAC-LC) and HE-AAC, the variant used for low-bitrate streams, both decoded from .aac files in our tests in Chrome, Edge and Safari on a Mac, in mono and stereo. Each one is turned into 16 kHz mono before transcription anyway.
A 64 kbps mono AAC recording takes about 0.5 MB a minute, so even a long one is quick to open.
How do you get the AAC sound out of a video?
For a transcript, you don’t have to: drop the MP4 or MOV here and the converter uses its AAC sound and ignores the picture. To keep the sound as a file, extract the audio as an M4A, which copies the AAC without re-encoding.
Can NoteOwl transcribe AAC files on a Mac?
Yes. NoteOwl imports .aac, M4A and MP4 recordings and transcribes them on your Mac with unlimited transcription, labelling every speaker. Nothing is uploaded, and every transcript stays searchable alongside your meetings.
FAQ
Questions about AAC to text
Is the AAC to text converter free?
Yes, free and with no sign-up: 3 files a day, with up to 30 minutes of each transcribed. The text can be copied, or downloaded in any of the four formats.
What happens to my AAC file?
Nothing leaves your device except short pieces of its sound. The browser decodes the file and sends those pieces, over a secure connection, to a cloud AI transcription service, which transcribes each one and deletes it. NoteOwl keeps no audio and no transcript.
Why does my .aac file show no length in some apps?
A raw .aac file has no index recording its length, so some players guess or show nothing. The converter counts the file’s frames before it starts, and the length it shows, like every time in the transcript, matches the recording.
Do I need to convert AAC to MP3 first?
No. To convert AAC to text, the converter decodes the AAC sound directly. Making an MP3 first would only re-compress the sound, which adds a step and can’t make the transcript any better.
Will a stereo AAC recording work?
Yes. Its two channels are mixed into one before transcription, so speech is kept whichever side it was recorded on. Mono files work the same way.
Which languages can the AAC recording be in?
Most widely spoken ones. The language is detected from each part of the recording and the main one appears with the transcript. A recording in a single language gives the cleanest result.
What if the AAC file is longer than 30 minutes?
The first 30 minutes are transcribed and the page tells you where it stopped. To cover the rest, split the file first, or use NoteOwl on a Mac, which transcribes recordings of any length.
Keep exploring
More audio to text tools
- Audio to text converterTranscribe audio to text free: drop in an MP3, M4A, WAV or other recording and get an AI transcript with times, as text, SRT, VTT or Word; nothing is stored
- FLAC to textTurn a FLAC file into text free in your browser: AI transcription with times, as text, SRT, VTT or Word; nothing is stored
- OGG to textTurn a OGG file into text free in your browser: AI transcription with times, as text, SRT, VTT or Word; nothing is stored
- Opus to textTurn a Opus file into text free in your browser: AI transcription with times, as text, SRT, VTT or Word; nothing is stored
- WebM to textTurn a WebM file into text free in your browser: AI transcription with times, as text, SRT, VTT or Word; nothing is stored
The same in other tools
AAC recordings into notes, privately on your Mac
Free to download. Runs entirely on your Mac.
macOS 26 or later · Apple Silicon (M1 or newer) · 16 GB memory minimum, 24 GB recommended
About NoteOwl
NoteOwl is private AI meeting notes and memory for the Mac. It captures meetings without a bot joining the call, labels every speaker, writes summaries and action items, and builds a memory of every conversation that you can chat with — fully offline, because the speech recognition and the AI run on the Mac itself. Dictation into any app is free; Pro is a one-time purchase.
NoteOwl pricing: what’s free and what Pro adds
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