I just noticed that trying to play any of the videos from https://www.ted.com either causes the WebProcess to use the 100% of the CPU meanwhile the video only shows a black square (with 2.12.0 and GStreamer 1.8.x) or a crash (with trunk and GStreamer 1.6.x). On the console the following errors are logged: (WebKitWebProcess:22541): GStreamer-CRITICAL **: Trying to dispose element appsrc1, but it is in READY instead of the NULL state. You need to explicitly set elements to the NULL state before dropping the final reference, to allow them to clean up. This problem may also be caused by a refcounting bug in the application or some element. (WebKitWebProcess:22541): GStreamer-CRITICAL **: Trying to dispose element webkitwebsrc0, but it is in READY instead of the NULL state. You need to explicitly set elements to the NULL state before dropping the final reference, to allow them to clean up. This problem may also be caused by a refcounting bug in the application or some element. Examples of URLs to reproduce this: http://www.ted.com/talks/james_b_glattfelder_who_controls_the_world http://www.ted.com/talks/charmian_gooch_meet_global_corruption_s_hidden_players