View Full Version : Anyone else starting to notice HDV artifacts/limitations to HDV?
Joe Busch December 17th, 2007, 02:46 AM Starting to realize how annoying HDV is for the stuff I'm shooting...
Seeing the grass flicker/dance because the HDV codec can't handle fast pans on blades of grass? Zooming in and out or panning is specifically where it happens... I've even noticed heavy blocks/pixelation on fast pans. Added with rolling shutter of CMOS censors. Most of the stuff that comes out of my FX7 is desaturated, some days much worse than others... all manual settings...
It's new technology, but I'm really starting to see the limitations of HDV... I'll post up some samples if anyone doesn't really understand what I'm talking bout.
It's great for static shots for the most part... adding in movement, pans and zooms appears to be too much for the codec to handle.
It's amazing the difference in resolution from SD, especially for the price... it looks amazing. But compared to real HD, HDV looks meh...
Chris Soucy December 17th, 2007, 03:32 AM Welcome to the club.
Yep, HDV has it's serious limitations.
No fast pans. No fast zooms. etc etc etc.
Guess what?
No suprises there then, it's a bit like shooting 24 fps film @ ASA 50 fercrisakes.
Suggestion?
Don't pan fast, don't zoom fast, let the talent do the movement.
Follow those simple rules and you can't go far wrong.
HOWEVER - if you think, for a moment, HDV can take the place of $400,000 bucks worth of whatever type of equipment, you are very sadly mistaken.
It can't, won't and never will. It's an intermediate to the ultimate goal, that just happens to be affordable to people like me, and you, who could not, in a fit, afford the sort of gear required a decade ago to get the results posible from it.
Anyway, I hear what you say, and agree.
It has serious limitations. If you think you can work within those limitations, then good.
If you're work requires working beyond those limitations, then you need to think of another medium.
Don't know if this is any help or not.
CS
PS: Must have been a good story, had an earthquake slap bang in the middle of it. Yes, everything's still standing (I think!).
PPS. Only a 4.2, a mere nothing. (Ahem, not quite sure the "express train underneath feet" feeling can be quite that easily forgotten. I'm an "eathquake virgin", but hey, if I'm living here, better get used to it!)
Tim Polster December 17th, 2007, 09:21 AM Joe,
I would like to see your examples.
To me, your post says it all.
I am waiting to go to HD and from what I see, some of the HDV cameras are a good value, and some of them seem overpriced for what they are replacing.
Detail isn't everything and I think the camera manufacturers knew that most folks would not be delivering in HD (Blu-ray...) so they went ahead with this middle format.
For the money, one could have purchased a nice 1/2" or even 2/3" SD cam (without filming limitations) for the price of some of these 1/3" HDV cams.
I don't like the idea of 'upgrading' to a camera that has smaller chips, is light challenged, forces me to film like movie set, and costs more!
Although I have seen some nice stuff from HDV cameras posted on this site.
A very confusing time to be a video operator.
Bill Ravens December 17th, 2007, 09:34 AM I'm pretty happy with the image quality of HDV, even tho' compression artifacts cause motion image problems. Guess that doesn't really bother me too much. The solution is right out of 24fps instruction manual...very slow pans. It certainly is better than DV ever was. What does bother me about HDV, however, is the very sensitive nature of the 4:2:0 color mapping to exhibit high levels of noise if any CCing is done. Even conversion to an intermediate, like Cineform, is very sensitive to much CC.
Joe Busch December 18th, 2007, 11:02 AM No fast pans. No fast zooms. etc etc etc.
Haha... I don't control my talent, I'm not directing them...
I shoot paintball... I'll see if I can find some raw .m2t files to upload that aren't too big.
HDV is a lot better than DV in 1 way... resolution... that means a lot to people... I'd like to compare HDV next to so P2 cameras or Sony equivalents...
Ethan Cooper December 18th, 2007, 02:48 PM I do weddings with my FX7 and I gotta say that on wide exteriors I get a lot of the whole "mosquito noise" problem. The codec does great on closeups, and sometimes this little camera looks great, but wide shots with lots of trees... forget it.
HDV isn't perfect, but darn it, sometimes it can look great.
I wish I had enough for the EX1 with it's more robst codec and better low light.
Mark Donnell December 18th, 2007, 03:04 PM Just a comment - I love the color from my HVX-200, but the sensitivity leaves a lot to be desired. Indoors, even when shooting 720p60 with a 1/60 shutter, I often have to add 6 db gain to get a good exposure, and noise is a mild problem even without the 6 db gain. All in all, I'm still happy because the color is so natural and saturated.
Ben Winter December 18th, 2007, 03:20 PM Exposure latitude makes me want to scream. But of course this has more to do with the hardware than the compression scheme. Still.
I had to deal with a beat-up tape the other day, and thanks to HDV's keyframe compression, every lost frame meant half a second of dropout. Ugh.
Ethan Cooper December 18th, 2007, 03:27 PM Just a comment - I love the color from my HVX-200...
...All in all, I'm still happy because the color is so natural and saturated.
I used an HVX for about a year and I agree about the color. It just has such a smooth, organic feel about it for a digital signal. I wish all cameras "felt" like that.
My impression of the HVX after using it for so long was that it was the best standard def camera ever made for the money. And yes, I know I said standard def. The soft 720p downconverted to SD looks as good or better than any high end SD camera ever made.
Again, these are opinions.
Levi Bethune December 19th, 2007, 11:52 AM I agree with you Ethan about the HVX-200. I used one for a month or so just to shoot SD and you can't beat the color. It just looked right.
I bought a JVC HD110u because it FELT right because I thrive off of the feel of a real(albeit cheap material) lens, manual settings and shoulder mount. With some tweaking the colors look good, and overall down-converting to SD in 60p and 24p is great, but no HDV codec is going to look like DVCPRO HD or XDCAM.
To me, it's a means to an end, and until I have the money to invest in something I want, I am happy with, and will gladly settle for something I need.
For someone coming from MiniDV or DVCAM and looking for higher quality without breaking the bank, HDV does just fine, and has some life in it still. But it's not where anyone should set up camp and expect to live happily ever after. Then again, in this industry, is there such a place?
[ /Preaching to the choir ]
David Moody December 19th, 2007, 08:05 PM One of the things I have noticed is macroblocking with water wave action.
I still think HDV will have less artifact than the AVCHD formats at their current bit rates.
The HV-20 shoots pretty good footage for a camcorder under $700. In good light I think it may be better than my FX1.
There are currently no good real HD options for the home movie crowd.
Joe Busch December 20th, 2007, 06:05 PM http://lousyhero.com/blaze/hdv1.jpg
Quick screengrab from a fast-pan... This was full HDV, highest settings in Vegas.
And the bunker in the background isn't really rolling shutter, it was leaning over already :)
http://lousyhero.com/blaze/hdv.m2t
There's the clip it's from... it's such a fast pan that it's hard to notice the artifacts...
Matt Vanecek December 20th, 2007, 09:56 PM I don't notice any artifacts. I guess the important thing to look at is, does the video look good when you play it? I mean, how many people are going to be going frame-by-frame looking for artifacts, CA, etc.? One thing I've noticed in many years of watching TV, film, and video, is that fast pans tend to blur things anyhow. I find it real hard to read the ads posted on the walls around the field at a football game (I try to watch a lot of football). Possibly HDV might generate more artifacts than a $100K camera, but the footage you posted looks pretty good. I'm watching the guy running (first time), not all the objects being panned past.
If you want stills, use a still camera. Moving pictures are always going to blur or artifact on high-speed action, unless you use high-speed shutters on high-speed film (or video, maybe). But for the money most of us can afford, that footage of yours looks pretty darn good.
This whole "HDV is intermediate" or "waiting for a better codec" discussion is moot, and as somebody pointed out on another thread, every new format gets the same critique. When I see cell phone footage posted on the nightly news, I'm not going to lose any sleep over whether I made the right move or not, with HDV. I made the right move *for me*, and I'm happy with the results. Be happy with your results, or think about making a different move. It's all so black-and-white for me--but then, I program for a living, so everything is a logical decision!
ciao,
Matt
Chris Barcellos December 20th, 2007, 11:49 PM It looks like Joe is also shooting at a high shutter speed to get the "Private Ryan" look. I wonder if that would contribute to some of the issues he is speaking of. I'm guessing most films are shot a lower shutter speed (180 degree I think refers to shutter being open 1/48 of a second. ) So shooting at 1/48 may smooth things out....
Joe Busch December 21st, 2007, 06:58 AM I shoot at 1/1000 all the time unless it starts raining, then I drop to 1/500 and if that's not enough 1/250...
Haven't had to go below that though :)
I've seen other artifacts that appear throughout the entire pan, and other issues when I run slow-motion... tiny things that I can attribute to HDV...
It's annoying at best... for $2500 I think it's a pretty decent camera, I guess I just want better.
Chris Barcellos December 21st, 2007, 10:57 AM I'm just curious if you see as much of the "artifacting" at a slower shutter speed. HDV does work on a GOP principle, where processor attempt to modify only changing information in each succeeding frame in the group of pictures. It would seem that motion blur at slower shutter speeds would be less stressful in the process.... Any wizards out there got a thought...
The other thing that could be at issue, is what you are viewing it on. I have a cheapy HD TV. On some big time broadcasts I receive over the air, like football games, I will notice some blocking in fast pans. Is it the what's going on in the camera, or is it at the truck at the football stadium, the uplink to sattelite, downlink to the local affiliate, or in how my TV process the signal.... Don't really know, but I know that most of the time, the pictue is spetacular.
Ethan Cooper December 21st, 2007, 11:30 AM The other thing that could be at issue, is what you are viewing it on. I have a cheapy HD TV. On some big time broadcasts I receive over the air, like football games, I will notice some blocking in fast pans. Is it the what's going on in the camera, or is it at the truck at the football stadium, the uplink to sattelite, downlink to the local affiliate, or in how my TV process the signal.... Don't really know, but I know that most of the time, the pictue is spetacular.
Ah, you've hit upon something there.
It's definitely NOT the cameras. These guys use top of the line cameras and are usually spitting a straight uncompressed signal to the truck. Where the blocking/artifacting is introduced is in the encoding that allows the HD to be broadcast. I believe all the networks use an MPEG2 based encoding scheme that falls into HDV like bitrates, and oddly enough you get very HDVish problems with this type of encoding.
Sooooo... maybe, just maybe there's something a bit broken in the whole MPEG2 lowish bitrate HD thing. I understand they pretty much have to do it this way due to current (and some legacy) equipment, but it'll be nice when the industry moves away from MPEG2 based encoding. Not sure when that will be though.
The great thing (bad thing) about technology is that something newer and better is always just a few years away.
Seun Osewa December 25th, 2007, 03:20 AM I shoot at 1/1000 all the time unless it starts raining, then I drop to 1/500 and if that's not enough 1/250...
Haven't had to go below that though :)
With such a high shutter speed you have less light, so you have to boost the gain, which leads to a noisy, dirty image. Apart from the fact that a noisy image is uglier, your HDV cam wastes precious bits trying to compress this noise leading to an increase in MPEG2 artifacts. That's further degradation. You'll also have a strobe-like effect even at a 60i or 60p recording or playback rate, which is very distracting. So I can't imagine why you would punish yourself in this manner!
Matt Davis December 25th, 2007, 09:21 AM I shoot at 1/1000 all the time unless it starts raining, then I drop to 1/500 and if that's not enough 1/250...
Apart from the fact that a noisy image is uglier, your HDV cam wastes precious bits trying to compress this noise leading to an increase in MPEG2 artifacts.
Another thing is that DCT compression like MPEG2 tends to look for edges and spends time on them, whilst using a broad brush to wash in areas of flat tone. By using a fast shutter speed, every frame is going to have lots of edges to sharpen. It can't 'hide stuff under the carpet' of a blurred background, say. So the bitrate budget goes almost entirely on edge enhancement rather than hiding those macroblocks.
Sports and water always did kill HDV. As does noise from high gain, but then the Z1 looks very clean with 3dB, and even 6dB isn't intrusive.
I'd give a slower shutter and lots of ND to keep the iris =< f4 a try, but it won't deliver the 'Top Gear' or 'Ryan' effect you're used to seeing. Sometimes one has to adjust style to suit the format.
Shawn McCalip December 26th, 2007, 01:11 PM On some big time broadcasts I receive over the air, like football games, I will notice some blocking in fast pans. Is it the what's going on in the camera, or is it at the truck at the football stadium, the uplink to sattelite, downlink to the local affiliate, or in how my TV process the signal.... Don't really know, but I know that most of the time, the pictue is spetacular.
Ethan is correct here- it's not your camera. Depending on how you receive your broadcasts, you're looking at an image that's been compressed like there's no tomorrow! An over-the-air broadcaster like a TV station only has so much bandwidth to play with, and on top of that, they don't even USE their full allotment of bandwidth so they have some extra wiggle room in case something goes wrong. Right now, broadcasters output their HD signals at around 18-18.5 mbps, which is a bit lower than the 25mbps for HDV. Some providers, such as cable or satellite, might even use a lower bandwidth. I've even heard a couple engineers talking about trying to send an HD signal through a 10mbps pipeline. That last little bit is only hearsay, so I'm not sure on the overall accuracy of that. But, from my limited experiences, any and all HD material gets compressed like you wouldn't believe before it hits the airwaves.
Ethan Cooper December 26th, 2007, 04:08 PM Ethan is correct here
Can someone please teach that phrase to my wife?
Ervin Farkas December 27th, 2007, 07:24 AM Can someone please teach that phrase to my wife?
Sorry man, that's just too hard... harder than encoding HDV to MPEG2... :)
Kevin Shaw December 27th, 2007, 09:07 AM Sooooo... maybe, just maybe there's something a bit broken in the whole MPEG2 lowish bitrate HD thing. I understand they pretty much have to do it this way due to current (and some legacy) equipment, but it'll be nice when the industry moves away from MPEG2 based encoding.
But note that it's MPEG2 in combination with low bit rates which causes problems, and in spite of that viewers have been content with MPEG2 encoding for almost everything they watch lately (both broadcast and DVD). HDV works fine for the price, and if you need something better the Sony EX1 looks promising for under $10K. Plus you can run HDV cameras in DV mode if desired to avoid HDV encoding issues, for what that's worth.
The only thing likely to replace MPEG2 is MPEG4, which is generally used at even lower bit rates with corresponding encoding perils. Either way you're not likely to see delivery options with bandwidth above ~35 Mbps or non-GOP encoding, so these issues aren't going away any time soon.
Graham Hickling December 27th, 2007, 02:22 PM You'll also have a strobe-like effect
Yeah I have to say I get a headache just thinking about watching those clips.
Framegrabs from any video footage - even commercial film - always look bad in one way or another. If it isn't artifacts it's motion blur....but then no-one actually watches footage that way .....
|
|