Check the audio inside the MP4
An MP4 can contain video and audio tracks. A silent clip or a screen recording without recorded speech has no spoken words to transcribe. The transcript does not extract text from slides or describe the pictures.
- Play the MP4 first and confirm that the speech track is audible.
- Upload the original MP4; changing a filename extension does not change its codec.
- Check the duration limit and review the transcript alongside the video, especially when a speaker refers to something on screen.
