Feature Request: Internal Proxy Server with Custom Headers for External Player Compatibility

Describe your suggested feature

Many Cloudstream extensions rely on custom HTTP headers—such as User-Agent, Referer, Authorization, and Cookie—to fetch and stream video content from protected sources. While the internal player supports direct header injection, it is currently limited:

  - Media3 ExoPlayer often fails to handle HLS streams correctly, leading to MediaCodec errors or undetected audio tracks.
  - As a result, many users are forced to use external players.
  - However, external players like VLC, MPV, and MX Player were able to play those files but wont get custom headers.

🧩 Problem Statement

  - Many sources require specific headers for access.
  - Internal player issues (e.g., with HLS or codecs) necessitate external playback.
  - External players do not reliably support header injection, especially for complex headers or cookies.
  - This causes many links to break, even though they are valid and playable with headers.
  - Extensions become harder to maintain, and users have a degraded experience.

🎯 Proposed Solution

  - Introduce a lightweight local HTTP proxy server within Cloudstream that:
  - Runs on a loopback address (e.g., http://127.0.0.1:12345).
  - Accepts a request with:
                  - a video or subtitle URL
                  - extension-defined headers
                  - Performs the request with headers applied.
                  - Streams the content back to the requesting external player.

Other details

No response

Acknowledgements

• My suggestion is NOT about adding a new provider
• I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open issue.

The issue names no files, tests, or entry points, so a contributor must first locate the external-player handoff and networking code. Done is not fully specified; the proposal describes a loopback proxy that applies extension-supplied headers and streams video or subtitle content successfully to external players.