Some video metadata fields are limited because target destinations like YouTube have strict field constraints.
Each destination we serve (e.g. YouTube, Facebook, etc.) has different rules regarding how long various metadata fields can be. We've normalized across various system constraints so you can enter the data just once, and can be assured the data will be acceptable by these common 3rd-party publishing platforms. For example, YouTube limits the number of characters in a description to 20,000, so we've also limited our description to that number.