Convert M4A to subtitles

Transform your M4A audio into professional subtitles in multiple formats. Perfect for converting Apple audio content to video subtitles.

SRT & VTT
5-min turnaround
All platforms
Audio
Video
DOCX
SRT/VTT
PDF
53+ Languages
About This Format

Understanding M4A files

What is a M4A file?

Apple's audio format with superior quality at small sizes

An M4A audio file is a lossless audio format (and encoding algorithm) created by Apple and utilized on a variety of Apple products (including iPod, iPhone, iPad, iTunes, and Quicktime products). The m4a codec has been open-sourced so it is quite popular. M4A files are usually encoded with Advanced Audio Coding (AAC) which was originally designed to be the successor to MP3.
Both MP3 and M4A files are used for audio-only files, and are both unprotected (free from DRM features). Protected files will have a *.m4p file extension. AAC or M4A files do have better audio quality when compared to MP3 files when encoded at the same bitrate due to some of the codec’s improvements such as compression based on perception and a smaller block size for changing audio sounds and signals.

Common Uses

  • iTunes music library
  • Apple podcasts
  • Audiobook distribution
  • Voice memos on iPhone

Audio Quality

Better quality than MP3 at same file size

Transcription Tips for M4A

  • Excellent for transcription - designed for clear audio
  • AAC encoding provides better speech clarity than MP3
  • iPhone voice memos use M4A by default

Where M4A Files Come From

  • Apple Music
  • iTunes Store
  • iPhone/iPad recordings
  • Voice Memos app
10x
Faster than real-time
Get your M4A subtitles in minutes
99%
Accuracy rate
Industry-leading AI for M4A files
53+
Languages
Subtitles in any language
30+
Export formats
SRT, VTT, FCPXML, and more
How It Works

Create subtitles from M4A in 6 steps

Step 1

Create account

Sign up for Sonix's free trial. Includes 30 minutes free.

Step 2

Upload file

Upload your M4A file from your computer or cloud storage.

Step 3

Select language

Choose from 53+ languages spoken in your file.

Step 4

Auto-transcribe

Sonix AI transcribes your M4A with word-level timestamps.

Step 5

Split subtitles

Customize line length, duration, and subtitle breaks.

Step 6

Export

Download subtitles as SRT, VTT, or other formats.

Common Questions

Everything about M4A subtitles

What subtitle formats can I export from M4A?

Sonix exports M4A transcriptions to SRT, VTT, ASS/SSA, SBV, STL, and more. Choose the format that matches your video software or platform.

Can I create subtitles from Voice Memos?

Yes! iPhone Voice Memos in M4A format work perfectly for creating subtitles. Great for adding captions to video versions of your audio recordings.

What's the best subtitle format for M4A content?

SRT is the most widely compatible format. For web video, VTT is preferred. Sonix supports both plus many professional formats.

How do I improve M4A subtitle accuracy?

Use clear recordings at 128kbps or higher. After transcription, use Sonix's editor to correct any errors before exporting.

Can I add speaker names to M4A subtitles?

Yes! Enable speaker labels when exporting subtitles. Sonix identifies different speakers in your M4A audio automatically.

Can I hardcode subtitles from M4A audio?

Sonix generates subtitle files you can import into video editors to burn into your video. Export to SRT and use your preferred video software.

Why Sonix

Professional subtitles from M4A files

Multiple Formats

Export subtitles as SRT, VTT, FCPXML, and more for any platform.

Customizable

Control line length, duration, and style of your subtitles.

Translate

Create subtitles in 53+ languages from your original audio.

Burn-in Option

Permanently embed subtitles into your video with one click.

Reviews

Trusted by content creators

4.98 rating from 211 reviews

The accuracy, that's what I like the most.
DV
Douglas V.
Santiago de Surco, Peru
Sonix is simple and very easy to use and the results were very nearly perfect. I would definitely recommended the site to anyone who asks me.
NL
Nathan L.
St. Thomas, Canada
Sonix is amazing. It’s like adding the most brilliant brain to my staff.
PM
Phillip M.
Bothell, WA USA
The highest accuracy I have ever achieved through similar services.
JB
John B.
Townsville, Australia
Sonix is faster and better than YouTube at making captions for my videos!
FN
Francisco N.
Concepcion, Chile
Impressed at how seamless Sonix makes editing transcripts. This is so much easier and more enjoyable than manually writing an entire transcript myself.
SA
Sean A.
Wellington, New Zealand
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