SoundCloud and MP4
There is no video on SoundCloud. Here is what that means.
By using this site you confirm you have the right to download the file you request.
Nothing to convert
SoundCloud is a sound platform. A track has no video track, so there is no MP4 to make — and this page offers audio rows only, which is the source telling the truth about itself.
For a while it did offer a bogus "MP4" row: a fallback written for LinkedIn was firing on every URL regardless of whether a video stream existed. It now requires one, which is why the row is gone.
What the other sites are giving you
An audio file wrapped in a video container with a still image — the waveform, or the cover art — so that it technically opens in a video player. It is an MP4 with nothing moving in it.
If you need that for an editor or an upload, make it there from the MP3 and whatever picture you actually want.
Frequently asked questions
Other sites offer MP4 for SoundCloud — how?
By pairing the audio with a still image. Nothing moves in the result.