Profile: TomT2847

Problem:

I want to do is use one of the CRED API hooks after the form is submitted to add a meta value to the corresponding post.

Solution:

Yes, you are right, you can use CRED action hook "cred_save_data" to update/add custom field to the post, see the document you mentioned above:

https://toolset.com/documentation/programmer-reference/cred-api/#csd

But, it needs custom codes, for example, when user submit the CRED form, the post is saved into database, you can use hook "cred_save_data" to trigger a custom PHP function, in this function, you need to:

1) get the value of "URL of the video uploaded", if it is a custom field created with Types plugin, you can use Types function types_render_field() to get the field value:

https://toolset.com/documentation/customizing-sites-using-php/functions/

Or you can use WordPress function get_post_meta() to get the value:
https://codex.wordpress.org/Function_Reference/get_post_meta

2) use above value to update/add it to the "meta value", for example
https://developer.wordpress.org/reference/functions/update_post_meta/

Relevant Documentation:

https://toolset.com/documentation/programmer-reference/cred-api/#csd