There is a id3v2.3 tag field "synchronized lyrics" (Field: SYLT)[1] where you can store a "phrase" with a "timestamp". One library I know that may support writi

There is a id3v2.3 tag field "synchronized lyrics" (Field: SYLT)[1] where you can store a "phrase" with a "timestamp". One library I know that may support writing this tag is atldotnet[2], while I did not try it out. At least there is a Type TRANSCRIPTION in the linked code segment. There is also LRC[3], a synchronized lyrics format stored in an extra file (*.lrc). [1]: https://id3.org/id3v2.3.0#sec4.10 https://id3.org/id3v2.3.0#sec4.10 [2]: https://github.com/Zeugma440/atldotnet/blob/749d9ccb0303266740181eb552724b8b6420fca2/ATL/Entities/LyricsInfo.cs https://github.com/Zeugma440/atldotnet/blob/749d9ccb03032667... [3]: https://en.wikipedia.org/wiki/LRC_(file_format) https://en.wikipedia.org/wiki/LRC_(file_format)