Most [0] the time you can swap ffmpeg for ffplay to get a preview window. So you could do something like the suggestion here [1] to get the preview window, and

Most [0] the time you can swap ffmpeg for ffplay to get a preview window. So you could do something like the suggestion here [1] to get the preview window, and then use GTK to embed the window wherever you wanted it. [0] But not all [1] https://github.com/kkroening/ffmpeg-python/issues/190 https://github.com/kkroening/ffmpeg-python/issues/190