HVX200a resolution 1080 or 720?

[Aaron Marshall]

Hi,

I've been having discussions with a good friend of mine about the HVX200a. I've used the camera a lot in the past. In my experience I get this gut feeling that shooting in 720pn is the best route to go. It opens up the HVX to so many frame rate options, and only stores the frames you need making your P2 cards go a lot longer. I loved the HVX in this mode. It felt like artistically manipulating a cinematic tool rather than video.

My friend's problem is; he thinks the HVX is optimized to shoot in 1080p but goes through an extra process to downrez to 720pn. To my understanding it seems like the first logical step, especially from such a small sensor array (no bigger than SD sensors like the DVX) would be to go to 720, then have some sort of uprez process from there expand it to 1080 and not the other way around.

Can someone (or many) please enlighten me?

My opinion of the HVX is this; I loved the DVX. I treat the HVX like it's a super DVX. I don't care about 1080p. I am just glad to be getting 720pn out of it with variable framerates. It basically is a super DVX. The sensors aren't much different to my understanding. The brain of the HVX has a better way of converting information from the CCD's and storing it.

Please correct me if I'm wrong. :) I want to fully understand once and for all.

Thanks!

-Aaron

[VenezuelanD]

If you do a search on this board you will find endless discussions about the resolution of the camera.

Its not a simple answer, the camera can resolve around 550? 560? TV lines of resolution and can be a bit soft when compared to other cameras.

Internally it does all its sampling at 1920x1080 before down converting to the format that you are shooting at. 720p is by far the most popular format with this camera and a very acceptable one. It gives you more temporal resolution (60 progressive frames) and shooting in native resolution gives you the most time per p2 card.
Shooting in 1080 does have its merits. Due to the fact that DVCProHD is a constant bit rate codec when you're shooting 720/24pn you're only using something around 40mbps instead of the full 100mbps DVCproHD can record in. When you're shooting in 1080i24pa the 24 frames are distributed over all 60i fields so you come closer to utilizing the codec more efficiently. What this means is that 1080 footage is slightly less compressed than 720 footage.

So basically DVCProHD1080 is the highest quality the camera is capable of producing, not so much because of increased sharpness but because of the milder compression of the codec. Having a larger frame also helps with filmouts and the like. You also get a hair more resolution in 1080 than in 720.

[Aaron Marshall]

Thanks Daniel. I appreciate your feedback. You seem like a smart guy. There's always room for improvement on any subject. I'm trying to shed light on it through my own personal vernacular. I don't think I'm wasting any space on the servers with my observations and questions. It will just add to the endless discussions, because if it is truly endless it must constantly grow, right? I'm just contributing to your stance. :)

Ok, I have another question. I like what you brought up about bandwidth. 100mpbs with 1080p vs 40mpbs with 720/24pn. If you're shooting 720pn, but overcranking to 60 frames per second would the bandwidth still be 40 or will it scale and go up to 100?

Thanks again

[William_Robinette]

To my understanding it seems like the first logical step, especially from such a small sensor array (no bigger than SD sensors like the DVX) would be to go to 720, then have some sort of uprez process from there expand it to 1080 and not the other way around.

Also remember, that the HVX reads all the sensors at once. Even though each sensor doesn't provide 1080p independently it doesn't matter, because it isn't how the camera works. It reads the whole sensor block, that with the spacial offset generates a full 1080p image that the HVX derives all other resolutions from.

[Barry_Green]

If you're shooting 720pn, but overcranking to 60 frames per second would the bandwidth still be 40 or will it scale and go up to 100?
Every frame is stored individually, so the more frames per second, the higher the bandwidth, up to a maximum of 100mbps. So 720/60p, or 720/24pN @ 60fps, both = 100mbps.

[grimrebes]

In the HVX and HPX, 1080 gains a tested 30% of resolution over 720 based on what I've read and seen.

Ultimately, the record mode is just one more tool on your belt. If you are going to do a film out or something of the sort and don't have the restrictions of storage space, then
1080 is a good start. If you are going to be doing a lot of repositioning in post, 1080 gives you the most space to do that.

And the sensors are the same size (or so they claim) as the DVX, but have a few more pixels crammed on them.

For me, I have limited space on my travels and final delivery rarely exceeds 720, and my traveling machine can't display 1080... so all thing being equal, 720 wins the vote most of the time.

But the flexibility being able to shoot anything from and around DV25, DV50 and then DVCProHD in 720 or 1080 in the same camera is something I have found surprisingly useful.

[brian hanson]

i'm sure this has been addressed somewhere but is there a way to deinterlace 24p 1080i(in order to simulate 1080 24pn)?

[VenezuelanD]

If you want 1080 24p then shoot in 1080i24pa. You will have to remove the pulldown in your nle (most will do it automatically though I have noticed that FCP sometimes does not do it on its own even when you check the button, either way you can still do it manually its under the tools menu I think (no access to FCP right now) near the bottom there is a remove advanced pulldown.

[Barry_Green]

Never de-interlace progressive footage. As VenezuelanD said, use 24pA mode. Just about any NLE will automatically work with it just as if it was 24pN.