f6ed40c93a
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1182 broke text and and closed caption extraction when introducing WebVTT support, by making the output buffers not have timestamps any more. Fix that by making the process functions copy buffer metadata when generating new output buffers. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1262>