Is Blu-ray worth it on a 720p TV?
One question I’ve been asked with frequency is, “If my TV is only 720p, will I actually benefit from Blu-ray’s 1080p resolution?” The short answer is, “Yes.”
While it’s true you won’t get the full benefit of 1080p, a 720p image has up to four-times the resolution than DVD’s 480i image. But there’s more than that, you still begin with a 1080p image so there is more native resolution to begin with.
Take for example a high-def television signal. This comes in either 1080i or 720p from cable, satellite or over-the-air broadcast. These images are not as highly detailed as Blu-ray, and have far more compression, yet they look great on a high-def television. And they look better than DVDs. Blu-ray looks even better still.
The maximum resolution of DVD is 480p, not 480i.
It is true that the maximum output resolution of DVD is 480p (set by DVD-CCA for analog output), DVD video is encoded at 480i. This is because older analog TVs don’t support progressive video. EDTVs would support progressive video. A progressive scan DVD player deinterlaces the image and outputs it as 480p video.
I said DVD has a 480i image because that is the originally encoded image, and Blu-ray is encoded progressively.