Why 1080p

[EDV]

Can anyone explain to me the difference between 1080p and 1080i? A tech article online stated that "consumers are virtually unable to spot the differences" on a modern TV display. If this is so, and consumers, viewers, or the public in general can't see a noticeable difference.. what's the point? I mean... what are the workflow or production advantages 1080p offers other than a theoretically smoother moving image?

 

[Razz16mm]

Can anyone explain to me the difference between 1080p and 1080i? A tech article online stated that "consumers are virtually unable to spot the differences" on a modern TV display. If this is so, and consumers, viewers, or the public in general can't see a noticeable difference.. what's the point? I mean... what are the workflow or production advantages 1080p offers other than a theoretically smoother moving image?

1080i is a compromise for lower broadcast bandwidth. 1080p gives you a theoretically more time coherent image. I say theoretically because rolling shutter cameras don't produce a time coherent frame anyway. For non broadcast delivery, i.e H.264 web video, interlaced originals can cause visual artifacts like more aliasing when recompressed.
A 1080p image can be broadcast as 1080i (1080psf) so for production there really is little reason to shoot 1080i unless it is for direct live broadcast.

 

[David Jimerson]

From the 24p & Frame Rates tute, here's a quick visual reference. Interlaced (i) image first; progressive (p) image second. The difference is more stark the more motion you have.



It's not even a "theoretically smoother moving image"; the actual motion cadence is the same between 60i and 60p.

On the HVX, though, when you're talking about the difference between the progressive 1080 frame rates it has -- 24p and 30p -- and the only 59.94 frame rate it has in 1080 -- 60i -- then yes, the motion in 60i is smoother, more live, but not because of anything having to do with interlaced vs. progressive. It's because there are 60 pictures per second making up the motion instead of 24 or 30, and again, the motion would be the same if it were 1080/60p. On the HVX, you choose 1080/60i because you want "live" motion. You choose 24p or 30p because you want the motion associated with them. (1080/60i and 720/60p have the same motion, too.)

The NUMBER -- 60, vs. 24 or 30 -- is what makes the motion smoother, not the letter -- i or p.

 

[EDV]

So let me get this straight David : 1080 60i / 50i on the HVX / HPX would not exhibit the motion artifacts and other problems normally associated with interlaced 1080i ? Or is it better to just stick to 720p on the HVX / HPX for smoother motion?

 

[David Jimerson]

So let me get this straight David : 1080 60i / 50i on the HVX / HPX would not exhibit the motion artifacts and other problems normally associated with interlaced 1080i ?

It will exhibit interlace artifacts, as illustrated above. But it will have the same smooth, "live" MOTION as 60p/50p.

Or is it better to just stick to 720p on the HVX / HPX for smoother motion?

You will avoid interlace artifacts that way, but the resolution will be slightly lower. I would certainly suggest 720/60p over 1080/60i if you want to do greenscreen.

 

[Razz16mm]

From the 24p & Frame Rates tute, here's a quick visual reference. Interlaced (i) image first; progressive (p) image second. The difference is more stark the more motion you have.

View attachment 78436View attachment 78437

It's not even a "theoretically smoother moving image"; the actual motion cadence is the same between 60i and 60p.

On the HVX, though, when you're talking about the difference between the progressive 1080 frame rates it has -- 24p and 30p -- and the only 59.94 frame rate it has in 1080 -- 60i -- then yes, the motion in 60i is smoother, more live, but not because of anything having to do with interlaced vs. progressive. It's because there are 60 pictures per second making up the motion instead of 24 or 30, and again, the motion would be the same if it were 1080/60p. On the HVX, you choose 1080/60i because you want "live" motion. You choose 24p or 30p because you want the motion associated with them. (1080/60i and 720/60p have the same motion, too.)

The NUMBER -- 60, vs. 24 or 30 -- is what makes the motion smoother, not the letter -- i or p.

I said nothing about motion smoothness. As your example illustrates, a progressive frame capture produces a more coherent image compared to an interlaced frame capture of two fields that are not time coherent.

 

[David Jimerson]

I said nothing about motion smoothness.

EDV (the OP) did:

Can anyone explain to me the difference between 1080p and 1080i? A tech article online stated that "consumers are virtually unable to spot the differences" on a modern TV display. If this is so, and consumers, viewers, or the public in general can't see a noticeable difference.. what's the point? I mean... what are the workflow or production advantages 1080p offers other than a theoretically smoother moving image?

I was addressing him (I quoted him).

 

[Barry_Green]

Addressing the initial question: most people can't see a difference between 1080/60i and 1080/60p. That's true. 1080/60p is literally twice as much information as 1080/60i is though, and as David pointed out, the interlacing artifacts make post a hassle on interlaced material.

Interlace is going to finally die with the next iteration of television broadcasting; interlace doesn't make sense in a world where all the displays are now progressive. It is still common today (many, if not most, HD channels are broadcasting 1080i instead of 720p) but for internet broadcast/streaming, interlace just doesn't make much sense, and since that's the way things are headed, you can expect that interlaced technology is going to eventually, finally, thankfully die out.

 

[Robert Ruffo]

It will exhibit interlace artifacts, as illustrated above. But it will have the same smooth, "live" MOTION as 60p/50p.




You will avoid interlace artifacts that way, but the resolution will be slightly lower. I would certainly suggest 720/60p over 1080/60i if you want to do greenscreen.

Uh no - plasma and LCDs cannot properly de-interlace 1080i so you will get combing artifacts. Only the very few CRTs out there can actually display 1080i as 1080i. 1080i on popular television is 1080p mastering/acquisition split into fields for broadcast and then reassembled by your TV's processor as 1080p full frames for display.

1080i assuming your TV is deinterlacing properly - which any modern TV can do fairly well - is fine as a delivery method for 1080p24 and 1080p30 material. All fiction TV shows are shot at 24p. What you see after the field are "seamed back together" by your TV is 1080p, the exact same thing as if the transmission were itself 1080p with that same material, rather than split into fields for broadcast and then re-assembled later. Only el-cheapo prods actually shoot 60 fields as 1080i acquisition - and this your modern flat panel will not know what to do with and it will look like crap.

What 1080i can;t do is properly display true 24p without 3:2 pulldown - but that's not a big deal. Very few displays can actually show you 1080p60 due to chip and screen limitations - and except for sports 60p is not always all that nice aesthetically anyway.

There is no reason to up broadcasting to 1080p - it would have no benefit at all except to users with very old and very cheap flat panels that can;t deinterlace 1080i content reliably.

720p is half the resolution of properly shot 1080i - and by properly I mean acquisition must be 1080p - only at the final stages are those progressive frames split for broadcast into interlaced pairs, each half of the resolution of the same slice of time.

 

[David Jimerson]

Uh no -

?

I'm not sure what you're arguing with me about. I don't see anything you said which conflicts with what I said. You're talking about a lot of things I didn't talk about and don't have anything to do with the question(s) I was answering, which pertained to the HVX/HPX170.

 

[EDV]

From my experience 720p on Vimeo or .mov .mp4 QuickTime clip is as high resolution as its viable on the web in 2013. This is for corporate videos, music videos, showreels, and documentaries I have seen. So I guess only those asking for a Blu-Ray version would expect 1080p, if most HDTV stations are opting for 1080i.

 

[David Jimerson]

From my experience 720p on Vimeo or .mov .mp4 QuickTime clip is as high resolution as its viable on the web in 2013. This is for corporate videos, music videos, showreels, and documentaries I have seen. So I guess only those asking for a Blu-Ray version would expect 1080p, if most HDTV stations are opting for 1080i.

These really aren't things I'd be worried about when choosing your frame rate. Delivery is a separate thing from acquisition.

What is it that you want to do, and what frame rate do you want, and why?

 

[EDV]

Okay lets say I want to shoot a music video where there's lots of movement ( choreographed dance ) in some parts, and only some movement ( steadicam ) in others. Filming it on the HPX170 + M3, so ideally I'd like to get the sharpest images the camera can produce, plus smooth film like motion. Video clip ends up on Vimeo as a 720p. REading this thread I'm thinking "better stick to 720p", but others say 1080 on the HPX is sharper.

 

[David Jimerson]

If you want cinematic motion, then you want 24p. 1080/24p will be a bit sharper than 720/24p, and will have a bit more color information in it. The advantages of 720 are in being able to use variable frame rates and being able to shoot in 24pN mode, which will save you card space and eliminate the need to worry about pulldown removal in post. Of course, if you want variable frame rates and aren't worried about card space, you can shoot 1080/24p for most of the project and just shoot 720 for the VFR.

Experiment with both and decide if the increased sharpness of 1080 is what you want.

 

[EDV]

Thanks for that David. I guess I might have to go over that 24p instructional video some time. Well I am in Australia and we use 25p here, not 24p, so I guess I will try 1080 / 25p.

 

[David Jimerson]

Well, then you don't have to worry about removing pulldown. The card space savings (25pN) and VFR stuff still apply, though.