My name is Alex and I am one of the Support Engineers at JW Player. I will be more than happy to assist you with your questions.
I am able to reproduce your Pinterest issue. I’ll have to escalate this to our engineers to see what they say. As soon as I hear back, I will post an update on this thread.
As for Tumblr, you can override for URL by doing the following:
If you are using the “Publish Mode” feature of the Account Dashboard, you can specify the URL via the “Video Page Permalink” field on the Metadata tab of the particular piece of content you are embedding.
I have heard back from one of our Product Managers and it does look like Pinterest may have changed something on their end that made our sharing integration with them not work anymore. A bug has been filed with our engineers for this issue and I will be notified of any updates. As soon as I get notified regarding this issue, I will keep you in the loop.
Please let me know if you need any more help or have any other questions.
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