Re: 720p vs 1080i

Hi all,

I'm hoping ya'll might be able to point me to a few resources about differences/advantages/etc of 720p and 1080i.

Thanks
Ian Flynn

It really depends on what you're shooting and for what purpose.

I most often use 1080p30. I find this the best combination of spacial and temporal resolution for all things except fast action sports where I'd choose the best possible temporal resolution.
If I'm shooting sports I choose between 720p60 and 1080i due to better temporal resolution.
If I'm shooting for broadcast I'd chose between the above two although I'm inclined to use 1080i if the results are for Standard def broadcast.
If I were shooting for film I'd probably choose between 1080p24 or 720p24.
I used 720p30 for digital signage because that was their spec.

I guess this means I have use for nearly every single HD frame rate and frame size depending on the circumstances.

Often the content and purpose dictates the choice.

In my personal opinion, I'd avoid 1080i as much as possible mainly because of the very nature of interlacing. Interlacing is my #1 enemy. If you want a high frame rate, 720p 60 is great and "downrezzes" perfectly to SD 480i and retains the 60 different temporal images per second. 1080i does technically have more picture detail than 720p no matter what anyone says or tries to say, but I'd just rather deal with and watch progressive material if given the choice, and 720p still looks fantastic! Of course full 1080p 60 (at the full 1920x1080 resolution) would look even better, but that's a pipe dream as far as "affordable" cameras are concerned for the time being.

Joe, I thought your comments on 1080i vs 720p60 downrez to 480i interesting. One reason to chose 1080i is that one may actually need the larger frame size to have more room to reposition the picture in 480i. I don't think it makes 1080i a "better" choice but it is one consideration.

In nearly every case I avoid Interlace when delivering SD DVD, Web, Digital Signage for example. The one exception was this decision to shot 1080i for 480i broadcast. BTW, after the shot the client decided on 16:9 SD so I'd have been more inclined to shoot 720p60 for that. For 4:3 I wanted maximum flexibility to reposition the frame to track the action (it was sports shoot).

Have you done 720p60 vs 1080i downconversion to 480i for broadcast?

No, I'm talking about downrezzing of an entire existing program, not a pan and scan version of it.

Thanks for all the input both of you!