How do I accurately convert my M4A files to closed captions? 
Sonix uses the latest automated transcription technology to convert your audio files (*.m4a) to closed captions. Follow these six steps and see how magical it is:
Step 1
Sign up for a free Sonix trial account—includes 30 minutes of free M4A to captions conversion.
Step 2
Upload the MPEG-4 Audio File file(s) (*.M4A) from your computer, Dropbox, Google Drive, or by dragging it on the page.
Step 3
Choose the language spoken in the uploaded M4A file. We support over 49 different languages including Russian, Chinese, Spanish, and English. Click the 'Start Transcribing Now' button.
Step 4
Sonix will then automatically transcribe the audio from your M4A file and convert it to a simple text format. Grab a cupcake, it will take only a few minutes.
Step 5
Use the Sonix AudioText Editor to polish your transcript before we convert it to a caption file. Simply type in your browser to correct any words in your transcript.
Step 6
Click the 'Export' button. Choose either 'Subrip subtitle file (.srt)' or 'WebVTT file (.vtt)' from the dropdown to download the closed caption version of your M4A file. You can also adjust the character length and time duration length of each caption.
That's it! Your M4A file has now been converted to closed captioning and is ready for the next step in your workflow!
Thousands of customers create closed captions from their M4A files with Sonix 
Frequently Asked Questions for MPEG-4 Audio File (*.M4A) to subtitle 
What is a M4A file?
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.
Does Sonix transcribe audio files with a *.M4A file extension?
Yes, Sonix does automatically transcribe audio files with a .M4A file extension. Sonix is an online audio to text converter. Convert any audio (mp3, m4a, wav, ...) or video (mp4, mov, avi, ...) file to text without installing any software! Sonix quickly and accurately transcribes *.M4A files and converts them to text in a subtitle format.
Know anyone who needs to convert MPEG-4 Audio File (.M4A) to subtitle?
We'd appreciate it if you tell them about Sonix—the best way to convert M4A to subtitle.
Other ways to convert your M4A audio files with Sonix
M4A to text
Use the most accurate speech-to-text technology to convert files: M4A to text.
M4A to docx
Accurately transcribe your M4A file to Microsoft Word Format (docx) so you can bring the transcript into your workflow.
M4A to PDF
Easily transcribe your M4A file to Adobe's Portable Document Format (pdf) so you can share them with colleagues.
M4A to subtitles
Create subtitles for your M4A files to make them more accessible for your audience.
M4A to srt
Quickly create subtitles from your M4A files and save them as SRTs, one of the most widely supported subtitle formats.
M4A to VTT
Create more advanced captions for your M4A files by using the latest caption format VTT (Video Text Tracks).
Create closed captions from your MPEG-4 Audio File files with Sonix 
Sonix automatically transcribes and translates your audio/video files in 49+ languages. Easily search, edit, and share your media files. Sonix is an online, fully-automated speech to text service that quickly converts MPEG-4 Audio File files to captions. Fast, accurate, and affordable. Millions of users from all over the world.
Includes 30 minutes of free transcription
