@Martin
Thank you very much for your support.

That was my final goal.
I use two fields in every post, each one for every URL.
I managed dome of my goals using the Javascript API references:
https://foliovision.com/player/developers/javascript-guide.

On the SoundCloud side, I had a misunderstanding which was my real problem.
I will tell it as I understand it:
The SoundCloud is on the oEmbed protocol thing for the WordPress and its URLs may be played by some player plugins. Most of them have no API, it is what it is from their GUI.
FVPlayer unfortunately, does not support the oEmbed thing, just YouTube URLs,

If I got it wrong, please current.
TnX