I am developing an audio player in Linux. I would like to use Gstreamer as backend. When I searched I came to know QMediaPlayer (Qt component) provides simple APIs for playback. Is QMediaPlayer is a wrapper over GStreamer APIs (QMediaplayer internally using GStreamer?) in Linux?
Yes, it is: https://wiki.qt.io/Qt_5.13_Multimedia_Backends. Qt6 also uses gstreamer. Qt 6.4 added a new ffmpeg backend.