Sony EX1 Severe LongGop Problems

[Bo Skelmose]

Hi
Maybe this could be an issue on the editing software – maybe some software/editing hardware are able to generate the right pictures from the long gop in the timeline and some are not. That could be the explanation why some have sharp pictures at every eight pictures and someone else do not have that problem ? just a thougt…

[Nick Lantz]

I may be chiming in a little late but I completely agree with Richard. I saw the problem immediately.
It was very obvious when panning across a crowd of people. Pretty much anytime you move the camera too quickly the image goes to mush. It is completely unusable when this happens. I shoot mostly hand held and I don’t think i will be making the jump to this new camera. In defense of the EX it does look great when you move very slowly and I was very impressed with the colors and resolution.

Not to be mean but if you didn’t notice this as a problem your just not looking with a critical eye. It is very obvious and something Sony will have to deal with at some point.

Nick Lantz
nlantz2005@yahoo.com

[Richard Ladkani]

HI Nick

have you read my last comment on the thread EX1 vs. Z7
I noticed that my shutter was set to 1/25 or set to OFF in 25p mode.
Did you try it with the shutter on?
It looks much better.

https://www.richardladkani.com

[David Bispham]

I view the footage on a Sony LMD-2050W played off the SxS card from the camera, so an edit system would not be the case in my situation.
As you can see in the above threads the problem should be resolved by changing the shutter speed. I am hesitant to do this because of the rolling shutter issue, so I figure If I stick with 720p 60 I should be OK, although I will continue to test this.

[Mike Schell]

Hi Richard-
The absolute definite way to evaluate this problem would be to record uncompressed video out the HD-SDI port and compare this result (on a frame by frame basis) to the video stored on your SxS cards. Then you can determine if the artifacts and blurring is caused by the compression or some other setting, such as shutter speed. (I suspect compression issues).

Long-GOP MPEG2 compression generally performs well, even with some motion. However, there are some situations where Long-GOP will fall short, especially in highly complex images, such as grass. MPEG2 P and B frames are created by comparing the current frame to the I frame and then compressing the difference. If subsequent frames within a GOP are radically different than the original I Frame, then this differencing approach can create artifacts.

So, in high-complex, high-motion situations, I-Frame only, will likely produce better results. Our Flash XDR portable recorder gives you this option. You can record in full-raster (1920×1080) Long-GOP 4:2:2 at 50 or 100 Mbps rates for most applications. This produces excellent video quality for most applications and is the most space efficient (longer record times).

But for the really complex moving images, you can select MPEG2 I-Frame only full-raster 4:2:2 recording at 100 or 160 Mbps rate. This mode would eliminate any of the motion artifacts caused by the temporal compression used in Long-GOP.

Flash XDR gives you the option to dial in the compression bit-rate and type of compression to match the situation. You can even record different bit-rates and Long-GOP / I-Frame only to the same Compact Flash card and then upload to your NLE.

Mike Schell
Convergent Design

[Steve Brown]

Hey Mike,

As you could probably tell from my post above, I’m a fan of the Flash XDR. When will it actually start shipping? And what about the Nano Flash? I use Panasonic HDX900s, so I don’t have the Long GOP issues, but there are some issues with DVC-ProHD too. I’d love to be able to by-pass that.

Steve Brown
10-20 Productions

[Amit Virmani]

Hi. I just bought the EX1. I’ve found a major problem on all my test footage. Any camera movement results in jumpy footage. At first I thought it was my cheap tripod, but today I tried zooming in and out on an otherwise locked shot. Same problem. After every couple of seconds there’s a jump, as if the picture is catchng up to where the camera is then.

Am I missing something, or should I ask Sony to fix something?

Thanks in advance!

P.S. The camera has the 1.05 firmware.

[Richard Ladkani]

Hi

I am pretty sure you are playing your footage back on a computer when you see the jumps, correct? If that is the case than your computer cannot play back Full HD in real time or doesn’t have the codec installed properly. Try playing back the footage on your camera and see if you get the same jumps. If yes then there is a problem with your camera if not it’s your computer.
Good luck
Richard

https://www.richardladkani.com

[Amit Virmani]

Thanks Richard. So glad you suspect that cos it just occurred to me somewhere in between the panic attacks too. I got a new MacbookPro, 2.5GHz / 2GB RAM, so I just took Full HD playback for granted. Is 4GB is the recommended RAM?

Played back some of the footage on the camera. From what I can tell it’s ok. But I’m going to hook up the cam to a friend’s Plasma screen tomorrow just to be sure. I’m a bit paranoid, the LCD screen being small and all.

Thanks again!

[Charles Taylor]

Much more motion blur on the EX1 shot you posted. Looks better to me than the Z7 shot, but horses for courses.

Couldn’t see the 8 frame pattern you mentioned, would it be possible for you to name a couple of sharp frames?