tests: enforce I420 format
Test was not enforcing a video format on videotestsrc. I420 was picked as it was the first format in GST_VIDEO_FORMATS_ALL which will no longer be true (gst-plugins-base!689 (merged)).
Edited by Guillaume Desmottes
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
Test was not enforcing a video format on videotestsrc. I420 was picked as it was the first format in GST_VIDEO_FORMATS_ALL which will no longer be true (gst-plugins-base!689 (merged)).