GH4 Moire baaad! Help! at DVinfo.net

Bill Grant · October 24th, 2014, 09:17 AM

Hey everyone. I have been shooting a bunch with my GH4 and noticing something alarming. I'm getting very bad moire when I'm delivering 720p. Patterns on shirts, bricks, pretty much anything with the possibility of moire is going crazy. Seems like though, when I look at the source UHD footage full scree, there is no moire. But in any compressed footage or in the editor even at full quality in a UHD project, I get it. Can anyone help me resolve this question? Notice in the photo which is a full res screen grab, there is no moire.

sample

Noa Put · October 24th, 2014, 09:21 AM

What program are you using to downscale?

Sander Vreuls · October 24th, 2014, 09:21 AM

Perhaps you could soften up the footage before downconverting?

Bill Grant · October 24th, 2014, 09:50 AM

Using Vegas 13. I would hate to soften an image since I'm shooting with this camera to get more detail and sharpness. right? btw, this is a 14MBps MP4 720p. I did render a UHD mp4 at 28mbps and the moire was still there. Not as bad, But strangely it's not in the source file.

Sander Vreuls · October 24th, 2014, 04:24 PM

While you may want the detail and sharpness as in 4k, detail requirements for SD, HD and 4k are different..
This is why 2/3rd inch broadcast cameras shooting HD have low pass filters in front of the sensor to limit the resolution, to prevent aliasing and moire problems.. You do not want detail and sharpness that you can not handle in the resolution you are outputting at..

Gary Huff · October 24th, 2014, 04:44 PM

Though this is not for Vegas unfortunately, I had to use Instant HD to make the DVD master for this because some of the detail in the wide shots was causing ugly mosquito noise in the SD downconversion.

You might look into Virtualdub to help alleviate the moire. It might do a better downscale than Vegas, but it will require some tinkering, I'm sure.

October 24th, 2014, 09:17 AM	#1
Bill Grant Major Player Join Date: May 2005 Location: Columbia,SC Posts: 806	GH4 Moire baaad! Help! Hey everyone. I have been shooting a bunch with my GH4 and noticing something alarming. I'm getting very bad moire when I'm delivering 720p. Patterns on shirts, bricks, pretty much anything with the possibility of moire is going crazy. Seems like though, when I look at the source UHD footage full scree, there is no moire. But in any compressed footage or in the editor even at full quality in a UHD project, I get it. Can anyone help me resolve this question? Notice in the photo which is a full res screen grab, there is no moire. sample moire test on Vimeo __________________ Cinema Couture www.cinemacouture.com

October 24th, 2014, 09:21 AM	#2
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,510	Re: GH4 Moire baaad! Help! What program are you using to downscale?

October 24th, 2014, 09:21 AM	#3
Sander Vreuls Regular Crew Join Date: Apr 2009 Location: Hilversum, The Netherlands Posts: 184	Re: GH4 Moire baaad! Help! Perhaps you could soften up the footage before downconverting?

October 24th, 2014, 09:50 AM	#4
Bill Grant Major Player Join Date: May 2005 Location: Columbia,SC Posts: 806	Re: GH4 Moire baaad! Help! Using Vegas 13. I would hate to soften an image since I'm shooting with this camera to get more detail and sharpness. right? btw, this is a 14MBps MP4 720p. I did render a UHD mp4 at 28mbps and the moire was still there. Not as bad, But strangely it's not in the source file. __________________ Cinema Couture www.cinemacouture.com

October 24th, 2014, 04:24 PM	#5
Sander Vreuls Regular Crew Join Date: Apr 2009 Location: Hilversum, The Netherlands Posts: 184	Re: GH4 Moire baaad! Help! While you may want the detail and sharpness as in 4k, detail requirements for SD, HD and 4k are different.. This is why 2/3rd inch broadcast cameras shooting HD have low pass filters in front of the sensor to limit the resolution, to prevent aliasing and moire problems.. You do not want detail and sharpness that you can not handle in the resolution you are outputting at..

October 24th, 2014, 04:44 PM	#6
Gary Huff Inner Circle Join Date: Jan 2013 Location: Austin, Texas Posts: 2,006	Re: GH4 Moire baaad! Help! Though this is not for Vegas unfortunately, I had to use Instant HD to make the DVD master for this because some of the detail in the wide shots was causing ugly mosquito noise in the SD downconversion. Where Snakes Roam You might look into Virtualdub to help alleviate the moire. It might do a better downscale than Vegas, but it will require some tinkering, I'm sure.