Free online ODT to AAC converter

When a phone or audio workflow needs a spoken recording instead of an editable document, an ODT file must be turned into narrated audio. The conversion reads the document’s text aloud and encodes the speech as AAC; it does not preserve the document as a document.

What the ODT format is

ODT (OpenDocument Text) is an open document format used for word-processing files. LibreOffice Writer and Apache OpenOffice Writer create ODT files, and the format is also supported by other office suites.

What the AAC format is

AAC (Advanced Audio Coding) is a lossy audio codec used for speech and music playback. It is widely supported by phones and media players and can provide good audio quality at relatively low bitrates. AAC files commonly use the .aac extension; the codec can also be stored in an .m4a container.

Convert the file online on 101convert.com

1. Open the ODT-to-AAC converter on 101convert.com and upload the document. The page allows batch conversion; its per-file size limit is shown there.
2. Set the voice language and reading speed before converting.
3. Start the conversion, then download the resulting AAC file or files.

Convert offline with desktop software

This free, open-source workflow uses LibreOffice to extract the document text, eSpeak NG to synthesize speech, and FFmpeg to encode AAC. These programs are available for Linux, Windows, and macOS, though installation steps vary by operating system.

1. In LibreOffice Writer, open the ODT and choose File → Save As. Select a plain-text format and save as input.txt.
2. Run eSpeak NG to create a speech file: espeak-ng -f input.txt -w speech.wav.
3. Use FFmpeg to encode the WAV as an AAC audio stream: ffmpeg -i speech.wav -c:a aac -b:a 128k -f adts output.aac. Change 128k to adjust the target bitrate.

Quality and limitations

The spoken file contains synthesized narration, not the ODT’s page layout, fonts, or images; tables and other complex formatting may not read naturally. The selected voice language affects pronunciation, and AAC encoding is lossy, so bitrate changes can affect audio quality and file size.