From best to worst:
Full 1080p resolution pumped out at up to 48 Mbps = the best picture quality currently available.
2 Over-the-air broadcast
Even though they use the older MPEG-2 standard, networks broadcast HD at a high data rate (about 19.4 Mbps), which puts cable and satellite to shame.
3 Cable/fiber (tie)
Cable companies use proprietary compression and won’t talk about bitrates, but the consensus is that they best the satellite services in picture quality.
Dish Network and DirecTV won’t talk about their tech either, but engineers believe that both providers transmit their HD programming at around 6 to 8 Mbps. Good enough for fourth place.
Walmart’s Vudu is the only video-on-demand service that offers shows in 1080p resolution (and with a decent data rate, at that), making it the highest-quality download service.
Although DVDs aren’t hi-def in resolution, their transfer rate of up to 9.8 Mbps means their quality is better than what most streaming services offer.
7 iTunes/Amazon (tie)
A hefty helping of compression and lower bitrates (around 3 Mbps) means a drastic falloff in quality from most download services.
InstantNetflix emphasizes seamless playback rather than picture quality. The slightest hiccup in your broadband connection seriously ratchets down the fidelity.
Put regular Hulu on a big screen and you’ll be constantly reminded that you’re watching TV over the Internet.