Free online MD to M4A converter

Some audiobook players and phones accept M4A but not Markdown files. Converting an MD file to M4A turns its written content into spoken audio; it does not convert an existing audio recording.

What the MD format is

An MD file is a Markdown document: plain text that can include headings, lists, links, and other lightweight formatting. Editors such as Visual Studio Code, Typora, and Obsidian can create or edit MD files. For speech conversion, the text is read aloud; Markdown symbols may need to be removed so they are not spoken.

What the M4A format is

M4A is an audio file format commonly used for AAC-encoded sound. It is supported by Apple devices and many phones, media players, and editing programs. M4A is suitable for storing spoken audio in a smaller file than uncompressed WAV, though AAC encoding is lossy.

How to convert MD to M4A

Online on 101convert.com

1. Upload the MD file on the converter page. Multiple files can be added for batch conversion; each file is subject to the size limit shown on the page.
2. Choose the voice language and reading speed.
3. Start the conversion, then download the resulting M4A file.

Offline with desktop software

On Linux, macOS, or Windows, use Pandoc to remove Markdown formatting, eSpeak NG to synthesize speech, and FFmpeg to encode the audio as M4A. Install those programs, then run these commands in the folder containing the input file:

1. pandoc input.md -t plain -o input.txt
2. espeak-ng -v en-us -s 160 -f input.txt -w speech.wav
3. ffmpeg -i speech.wav -c:a aac -b:a 128k output.m4a

Replace input.md and output.m4a with your filenames. Change en-us to an installed eSpeak NG voice and adjust 160 for the desired reading speed. FFmpeg’s -b:a 128k sets the AAC bitrate.

Quality and limitations

The result is synthesized speech, not a copy of audio embedded in the MD file. Voice choice, language, and reading speed affect intelligibility; links, code, and unusual Markdown formatting may not be spoken naturally. Higher AAC bitrates increase file size but do not improve the pronunciation produced by the speech engine.