I need to apply the following CORS headers so I can use sharedArrayBuffer which is required by FFMPEG.

<IfModule mod_headers.c>
     Header set Cross-Origin-Embedder-Policy "require-corp"
     Header set Cross-Origin-Opener-Policy "same-origin"
</IfModule>

With this code in my .htaccess I am able to use sharedArrayBuffer (great) but now I cannot load data from firebase, it is blocked.

net::ERR_BLOCKED_BY_RESPONSE.NotSameOriginAfterDefaultedToSameOriginByCoep 200 (OK)

I have tried creating a cors.json to allow firebase storage, but it still does not work.

[
  {
    "origin": ["https://mydomain.io"],
    "responseHeader": ["Content-Type", "Authorization"],
    "method": ["GET", "HEAD", "POST", "PUT", "DELETE", "OPTIONS"],
    "maxAgeSeconds": 3600
  }
]

I also tried to apply the headers only on the /register route which is where I need the headers applied, but it still does not work even though if i do a curl request to that url it shows the headers are set?

I am very confused and not too familiar with writing code on the server with .htaccess, but I’ve not been able to crack this after many days of trying.

I hope someone can guide me the right direction!