How to Chromecast from a Mac to a TV

A Mac has no Cast button. This video shows a native player, written in Osprey, that finds every Chromecast and Google TV on the network and plays a local MP3 on one with full controls.

The full write-up, with the code and its limits, is How to Chromecast from a Mac to a TV.

Osprey is actively evolving.

Transcript

1. 0:00 A Mac has no Cast button. Chrome casts a browser tab, but it won't play an MP3 from your Mac on the TV with proper controls. This native player does.
2. 0:11 It finds every Chromecast and Google TV on your network by name. Open an MP3, pick a TV, and press play.
3. 0:18 Pause, seek, volume and speed all work, and the controls show what the TV reports. With ffmpeg installed, the TV shows a moving spectrum of the music.
4. 0:30 A Chromecast never receives your file directly.
5. 0:33 The player finds TVs, opens a TLS session, and launches the default media receiver. Then it serves the file over HTTP from your Mac, and tells the TV where to fetch it.
6. 0:46 Discovery uses the dns-sd tool that macOS already ships. Nothing extra to install.
7. 0:53 The whole interface is one data file of state machines and skins. The only code is this adapter, which answers each request with the Chromecast package.
8. 1:02 An unknown request becomes an error on screen, never a silent no-op.
9. 1:08 Every byte goes through one algebraic effect. In the tests, a handler plays the TV, so four whole journeys run with no window and no network.
10. 1:17 All four pass.
11. 1:19 What to know first. It plays MP3 files only, it runs on macOS, and it does not verify the TV's certificate.
12. 1:27 Build Osprey, then open the player. Osprey is actively evolving. Try it on your projects, and tell us what breaks.