It most cases users looking for mp4 to txt conversion would like to create a transcript from a multimedia file (for example .mp4) and save it in text format (such as .txt), thus in essence turning audio (speech) to text.
You can do this, but you will require the services of some special transcription platform, for example VoiceBase. The resulting text file may require some manual editing tho, as no transcription service by done program is perfect and almost always requires human input.
Updated: June 15, 2023