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View Full Version : Weird pixelated image at 1080p24 1/48 shutter.



cristiansoares
08-27-2009, 05:54 PM
Guys, I've been reading this forum for a long time even though I'm not a guy who post too often, so thank you all for many tricks and tips.
I've got a problem and I don't know if any of you have ever experienced this but as you can see from the screen grab below my picture at 1080p24 1/48 shutter is rather blocky. Any ideas of what mught be causing this because I know for sure that i got cleaner crispier pictures at this res before. Is it a SDHC Card issue? a Codec Issue? Honestly I've got no idea but this is making me start to think about switching this with the PMWEX3 and pay the extra few bucks. Need help!

My scene file as is:

Detail +4
V Detail 0
Detail Coring +3
All the rest default scene 6

I thank you all for any suggestions! HELP!

Christiano Soares
Charlotte, NC

Zacatac
08-27-2009, 06:01 PM
I've gotten that alot with my HMC, did you try to color correct it? or covert it to anything? I find AVCHD mts files fall apart and start banding and blocking without pushing any color correcting on it at all

cristiansoares
08-27-2009, 06:08 PM
This file came straight from the card on a mac playing through VLC 0.9.8 (intel). I will log and transfer to FCP and see what kind of results I get.

I think overall the camera is excellent but I just a little disappointed with some of the footage. especially at 1980x1080. When I connect it through HDMI seems that i get a much better picture though.

I will bring this file to FCP and post the results. Hopefully this is just VLC freaking out with the codec.

Thanks for the help!

cristiansoares
08-27-2009, 06:34 PM
Ok this is what I got from transcoding to FCP Prores 422 (HQ). I don't see much difference, so I'm guessing its on the camera side?

Dont't flame me for this conjecture but what if a shot has too much detail that its only limited by the maximum bit rate (21 mbit) to a point where it needs to increase the compressing therefore increasing blocking, jaggedness? Make sense?
I don't know but any input would be very appreciated.

Thanks again!

Christiano Soares
Charlotte, NC

Cranky
08-27-2009, 09:55 PM
Looks ok to me. Could you encircle the parts that are blocky?

cristiansoares
08-28-2009, 07:15 AM
So i detached the problem areas for me.
Have anyone ever had this problem?
You know, sometimes I love the picture this camera delivers and other times I just hate it... I wish I just loved it though...

Christiano Soares
Charlotte, NC

cristiansoares
08-28-2009, 07:23 AM
I shot this same evening, same card and settings, but the image is noticeable less blocky. I cant understand.

TheDingo
08-28-2009, 11:24 AM
If you use a HDMI cable to connect the camera to a good HD TV set, do you still see the same blockiness when playing the video from the SDHC card?

cristiansoares
08-28-2009, 05:23 PM
If you use a HDMI cable to connect the camera to a good HD TV set, do you still see the same blockiness when playing the video from the SDHC card?
Im afraid so... just checked with the hdmi cable and it is still there. Bummer! What might be causing this and how to avoid it to happen when recording with a client? :crybaby:

mcsmooth
08-28-2009, 08:17 PM
Honestly, I'm not sure I would have noticed if you hadn't pointed it out. Doesn't seem that bad. Is it as noticeable when watching the video play or just on still frames? Are your client's noticing?

If you are on a tripod, it likely does not have much to do with the codec, there is plenty of bandwidth in there so long as motion isn't way over the top. It is 4:2:0 (as is the EX3), so neither cam will get you perfect color detail.

It certainly wouldn't hurt to try turning the detail down a bit, 4 is on the higher side. Not sure if that will be enough to make you happy though.

Do consider that these cameras use chips that are 1/4 the resolution of 1080p. Pixel shifting really helps out with detail, but it does have its limits. Consider that the benefits of pixel shifting start to go away on colors that do not have color in R, G, and B. I tend to notice this most in areas that are all blue or red. I'm not an expert on this, but my guess would be that it may have do to with this concept since your problem areas are the blue V, red-ish lights and red flowers.

If you look closely at the break lights in the dark still (that you said was less blocky), you'll notice that they are indeed blocky... but it really isn't noticeable unless you are pausing the frame, zooming in and staring. The blue V might be an exception since it isn't moving and is on top of a highly contrasting detail.

An EX3 is certainly going to be sharper, but I'm sure you must have known that before you bought the camera. If not, look up on it, and be sure to also consider it has its own down sides. CMOS can be a good choice if you are primarily shooting detailed landscapes without too much motion. Just be sure not to obsess too much over every detail on freeze frames, even the best cameras will still have artifacts!

cristiansoares
08-28-2009, 08:34 PM
Honestly, I'm not sure I would have noticed if you hadn't pointed it out. Doesn't seem that bad. Is it as noticeable when watching the video play or just on still frames? Are your client's noticing?

If you are on a tripod, it likely does not have much to do with the codec, there is plenty of bandwidth in there so long as motion isn't way over the top. It is 4:2:0 (as is the EX3), so neither cam will get you perfect color detail.

It certainly wouldn't hurt to try turning the detail down a bit, 4 is on the higher side. Not sure if that will be enough to make you happy though.

Do consider that these cameras use chips that are 1/4 the resolution of 1080p. Pixel shifting really helps out with detail, but it does have its limits. Consider that the benefits of pixel shifting start to go away on colors that do not have color in R, G, and B. I tend to notice this most in areas that are all blue or red. I'm not an expert on this, but my guess would be that it may have do to with this concept since your problem areas are the blue V, red-ish lights and red flowers.

If you look closely at the break lights in the dark still (that you said was less blocky), you'll notice that they are indeed blocky... but it really isn't noticeable unless you are pausing the frame, zooming in and staring. The blue V might be an exception since it isn't moving and is on top of a highly contrasting detail.

An EX3 is certainly going to be sharper, but I'm sure you must have known that before you bought the camera. If not, look up on it, and be sure to also consider it has its own down sides. CMOS can be a good choice if you are primarily shooting detailed landscapes without too much motion. Just be sure not to obsess too much over every detail on freeze frames, even the best cameras will still have artifacts!

I think you're right, I will start shooting on 720p24 from now on switching to 60f for slow mo. I hope this will minimize the pixel shifting. and return better pictures. I really love this camera don't get me wrong specially after long hours on a glidecam, and we just shot a short film where the main cam was sony z5 and to tell you the truth, i like how sharp that cam was there on the monitor but it's a little hard to trade panny colors and tapelless work-flow for hdv again..... i guess i will keep this cam... for now :grin:

:dankk2: Appreciate all of you that came to my rescue! :thumbup:

ArtByHumanDotCom
09-02-2009, 11:33 AM
Hey Cristian-

Its funny that I came across this post:

This may help:

*Note: The Scene File setting tweaks were as follows:


Detail: +2
VDetail: +2
Detail Coring: +1
Chroma +2 (I think this should probably be returned to 0 as the resulting image becomes just a little too saturated, but you might prefer this)
Master Ped: -20
Cine-Like V

Referenced from: http://wilsonedit.blogspot.com/


On a side note: You and I should meet up. I am in the market to upgrade to a HMC150. I am here in Charlotte as well working with Underground Racing producing small videos for their marketing campaigns dealing with their modified Lamborghini's. Stay in touch or PM me if you are remotely interested- Check out their new forum and look under "Videos":

www.Lambopit.com

BOBBYTRASH
09-02-2009, 11:59 AM
Hey Cristian-

Its funny that I came across this post:

This may help:

*Note: The Scene File setting tweaks were as follows:


Detail: +2
VDetail: +2
Detail Coring: +1
Chroma +2 (I think this should probably be returned to 0 as the resulting image becomes just a little too saturated, but you might prefer this)
Master Ped: -20
Cine-Like V

Referenced from: http://wilsonedit.blogspot.com/


On a side note: You and I should meet up. I am in the market to upgrade to a HMC150. I am here in Charlotte as well working with Underground Racing producing small videos for their marketing campaigns dealing with their modified Lamborghini's. Stay in touch or PM me if you are remotely interested- Check out their new forum and look under "Videos":

www.Lambopit.com (http://www.Lambopit.com)


nice scene file :]

cristiansoares
09-02-2009, 05:10 PM
To ArtByHymanDotCom

That's very nice. I will check for improvments. I will PM you soon. Thanks! :thumbup:

mcsmooth
09-05-2009, 12:11 PM
I think you're right, I will start shooting on 720p24 from now on switching to 60f for slow mo. I hope this will minimize the pixel shifting. and return better pictures.
I actually wasn't suggesting using 720p to avoid pixel shifting. Pixel shifting is a good thing on this camera, it is what gives it its sharpness! I was just saying that it doesn't help in rare situations (shouldn't hurt though). 1080p will be a tad sharper and provides quite a bit more chroma information. I used to shoot everything 720, but now I only use it for 60p, or very rarely in 24p if there is going to be ridiculous amounts of movement.