Is It possible that people can upload music inside my game and that music should be played at start of layout?
This isn't supported mainly because all audio has to be dual-encoded in to both AAC and Ogg Vorbis. This would mean anyone uploading music would have to also dual-encode their upload, which is pretty complicated.
Ok, but is it possible to have any upload button function in my game. (For knowledge only)
And can it upload to my server.
You could probably do it using the plugin SDK. We can't really have a built-in feature for that, because it depends on your server.
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Thanks