generate questions: High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable, IPTV (including GoogleTV Roku boxes and AppleTV or built into "Smart Televisions"), Blu-ray video disc (BD), and internet downloads.
Roku and AppleTV are examples of what? {sep_token} Internet downloads, Blu-ray videos, and Apple TV are examples of what? {sep_token} Terrestrial broadcast and direct broadcast satellite are examples of what? {sep_token} Digital cable and Roku are examples of what? {sep_token}