Supprt extending QtMultimedia features via properties

QtMultimedia framework is greate but apis are not enough for me(and many people i believe). For example I want an option to select hardware accelerated decoder or software decoder. If there's no such api in current version, a possible solution I think is writting a mediaservice plugin(via libmpv for example) and using qt's greate meta property system, and the user code would look like player.setProperty("decoder", "gpu"). But when writing a mediaservice plugin I find there's no way to read/write QMediaPlayer's properties from QMediaPlayerControl, which means no matter how many features my backend supports, QtMultimedia user can not have them.