smpte: Fix integer overflow with possible heap corruption in GstMask creation.
Check that widthheightsizeof(guint32) doesn't overflow when allocated user_data for mask, potential for heap overwrite when inverting.
Fixes #1231 (closed)
Check that widthheightsizeof(guint32) doesn't overflow when allocated user_data for mask, potential for heap overwrite when inverting.
Fixes #1231 (closed)