Localhost is not the name of your home server
An address containing localhost refers to the machine making the request through its loopback interface. RFC 6761 reserves localhost names for that purpose. If a media tool opens a localhost address on a computer, copying that address to a television does not tell the television to contact the computer. It tells the television to look at its own local environment.
This distinction often appears when testing software that serves authorised local media or a companion web interface. A successful browser page on the server computer establishes a useful local test, but it does not establish access from another device. Record where the server runs and where the client runs before changing credentials or comparing internet speed.
A hypothetical two-device test
Suppose an owner starts a local demonstration server on a laptop and opens its localhost page successfully. The same text entered on a phone fails. That is not evidence that the phone rejected the video codec, because it may never have reached the laptop at all. The address itself is the first question to resolve.
Consult the server application's documented local-network access instructions. It may provide an appropriate network address, require an explicit listening configuration or limit access to local use. Do not invent an address from a product name or assume every development server is intended for other devices. Use a supported setup on a network you are authorised to administer.
Keep local access separate from internet exposure
A documented address reachable on a home network is not automatically intended for the public internet. Do not open router ports, disable a firewall or publish a private server address just to fix a localhost misunderstanding. Those are broader configuration decisions with different consequences. First establish the supported local route and the actual client-to-server connection.
If the server supplies a private access token in its link, treat that token as confidential. A local address does not make a credential harmless. For a public report, describe the address type and device roles while removing access-bearing paths and queries. Support can ask for a private diagnostic reference if the application needs one.
Retest from the intended client
Once a supported network route is configured, open it on the actual phone or television. Check the interface first, then select an authorised sample and record playback separately. Reaching the menu does not prove all media formats work, but it confirms progress beyond the original loopback-address problem.
Keep a short note with the server device, client device and documented connection method. If a network address later changes, return to the application's supported discovery or address instructions rather than falling back to localhost. The practical lesson is about endpoint identity: the same address text can mean the requesting device itself, not the remote machine the viewer had in mind.
Questions answered
Can I paste a laptop's localhost URL into a TV?
It will refer to the TV's loopback environment, not automatically to the laptop. Use the server application's documented network-access method.
Should I open internet ports to solve this?
First establish the supported local-network route. Public exposure is a separate configuration decision and is not required merely because localhost was misunderstood.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.