Retrieving Script Embeds Before Rendering Content

Here is my scenario:

I have thousands of posts that contain embedded content through an obscure video platform. These specific embeds are made via <script> calls. When the AMP plugin sees these, it strips them out. But I need the video embeds on my AMP pages.

To solve this, I would like access these strings before the AMP plugin strips them out, so that I can turn them into proper AMP markup. That is, so I can turn a string like this…

<script src="https://embed.site.com/id.js?id=123"></script>

…into a string like this:

<amp-iframe src="https://video.site.com/player.html?id=123"></amp-iframe>

I already have the difficult part: The regex to retrieve, transform, and render the strings. But I don’t know how to architect it to actually retrieve the strings. The default AMP template way to write out post content is this:

echo $content = $this->get('post_amp_content');

But by the time that runs, the <script> has already been stripped out, so I cannot run my regex to retrieve it. A possible solution might look something like this:

// run native wordpress content method...
$content = get_the_content();

// now run my regex...
$content = runMyRegex($content);

// now make it amp...
$content = makeItAmpCompliant($content);

echo content;

But I cannot find anything like a makeItAmpCompliant() method. Does such a thing exist?

Or maybe there’s a completely different way to do this that I am not thinking of.

Thanks for your help!