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GStreamer QT Overlay on Video Frames

GstQtOverlay is a GStreamer plug-in that renders QT graphics on top of a video stream. This rendering occurs directly into the GStreamer video frame buffer, rather than in physical graphics memory, with the resultant video having the QT graphics image merged into the video image. This brings together the best of the two worlds:

  • Modularity and extensibility of GStreamer

  • Beauty and flexibility of QT


With the RidgeRun GstQtOverlay element, GUIs will be available not only at the video display, but also embedded in file recordings and network streaming, for example.


GstQtOverlay makes heavy use of OpenGL in order to achieve high performance overlay rendering. The pixel blitting and memory transfers are done by GPU and DMA hardware accelerators, allowing real time operation at HD resolutions. As a consequence, the CPU remains free for other processing.

Graphics are modeled using QT's QML, which enables fast, powerful and dynamic GUI implementation. QML is loaded at runtime so there is no need to recompile the GstQtOverlay plug-in in order to change the GUI. Having QML independent of the GStreamer element speeds up development time, eases quick prototyping and reduces time-to-market without impacting performance. A single GstQtOverlay element is able to handle many different GUIs.

Learn more about the GStreamer QT Overlay element in our developer wiki here

Get more complete information by visiting our updated product pages - Click Here

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