Use AirPlay to stream video from Safari or QuickTime Player
In OS X El Capitan or later, you can stream certain videos to your Apple TV from Safari or QuickTime Player (version 10). Click the AirPlay icon 
(if available) in the playback controls, then choose your Apple TV.
Use AirPlay to mirror or extend your Mac display
When your Mac display and Apple TV are awake, choose your TV from the AirPlay status menu 
in the menu bar. You can then use the same menu to:
- Mirror your Mac display or use your TV as a separate display that extends the desktop of your Mac display.
- Turn off (disconnect) AirPlay. Pressing the Menu button on the Apple TV remote also turns off AirPlay.
Get help
If you don't see the AirPlay icon in your menu bar, make sure that your Apple TV is awake and meets the system requirements.
If you don't see your Apple TV in the AirPlay menu, make sure that your Mac and Apple TV meet the system requirements. Also check your firewall settings:
- Choose Apple menu () > System Preferences, then click Security & Privacy.
- Click the lock icon, then enter an administrator name and password.
- From the Firewall tab, click Firewall Options.
- Make sure that “Block all incoming connections” is not selected, and “Automatically allow signed software to receive incoming connections” is selected.
If AirPlay disconnects by itself, your wireless network might be too busy or have too much wireless interference to maintain the AirPlay connection. Learn how to troubleshoot Wi-Fi connectivity issues.
If your desktop doesn't look good on your HDTV, your HDTV might be using picture-quality enhancements that aren't best for computer images. Check your HDTV manual for information about how to adjust your HDTV settings for use with a computer. Your HDTV might offer a more suitable viewing mode, such as computer mode or game mode. Also try adjusting HDTV settings such as sharpness, detail enhancement, and noise reduction.
Requirements for using AirPlay
Here's a quick way to find out if your Mac supports AirPlay: Choose Apple menu () > System Preferences, then click Displays. If you don't see a “Show mirroring options in the menu bar when available” checkbox, your Mac doesn't support AirPlay.
Minimum requirements if your Mac and Apple TV are on the same network:
- Apple TV (2nd generation or later) with the latest Apple TV software
- And any of these Mac computers with OS X Mountain Lion v10.8 or later:
To find out what network your Apple TV (4th generation) is using, go to Settings > Network. On earlier Apple TV models, go to Settings > General > Network. The Apple TV should be on the same network as your Mac.
Minimum requirements for peer-to-peer AirPlay, which lets visitors connect their Mac or iOS device to your Apple TV without passwords or connecting to your Wi-Fi network:
- Apple TV (3rd generation rev A, model A1469 or later) with the latest Apple TV software
- Mac (2012 or later) with OS X Yosemite v10.10 or later