DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   JVC GY-HD Series Camera Systems (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/)
-   -   Problems with GY-HD110 film shoot (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/92167-problems-gy-hd110-film-shoot.html)

John Mitchell April 25th, 2007 11:58 PM

Claude - if you need to correct for the stuck pixel you can apply similar techniques to the camera's own inbuilt pixel compensation using a post program like Combustion or After Effects. Basically you need to copy information from a surrounding pixel and shift it one pixel across or down to cover the stuck pixel. You could even vary this over time if you found copying the same pixel too noticeable.


I'd be interested to know if the stepping you are seeing in the light graduations is before or after post processing. This stepping in colour reproduction is a result of imprecise 8 bit processing - basically when performing math on an 8 bit codec using 8 bit processing, you multiply the errors caused by not having millions of colours. This causes these annoying steps in smooth colour graduations. I'm not sure how the camera processes internally (I thought it was 10 bit). If you go straight to a 10 bit codec (like Cineform or Avid's DNxHD, both of which have 8 and 10 bit versions) and process everything in 16 bit you may be able to get around this.

Claude Mangold April 26th, 2007 04:55 AM

Thank you, John.

The stepping is visible before post, especially when viewed on a full-HD monitor - and in the final edit. It is less noticeable in SD.

We did not try to mask the pixel(s) yet in post as this was a (successful)screener only, but we'll have to do it if we take it to festivals. So your tip about cinform is welcome as it will allow us to clean up the scene.

John Mitchell April 26th, 2007 05:06 PM

Quote:

Originally Posted by Claude Mangold (Post 667747)
Thank you, John.

The stepping is visible before post, especially when viewed on a full-HD monitor - and in the final edit. It is less noticeable in SD.

We did not try to mask the pixel(s) yet in post as this was a (successful)screener only, but we'll have to do it if we take it to festivals. So your tip about cinform is welcome as it will allow us to clean up the scene.

When you say a full HD monitor do you mean a broadcast CRT monitor or an LCD/ Plasma TV set? I only ask because LCD's and Plasma do their own internal processing to resize to their native resolution and they generally only do this in 8 bit. However, given your workflow it seems more likely these errors are being introduced by the camera's own processing.

Claude Mangold April 27th, 2007 08:56 AM

Quote:

Originally Posted by John Mitchell (Post 668151)
When you say a full HD monitor do you mean a broadcast CRT monitor or an LCD/ Plasma TV set? I only ask because LCD's and Plasma do their own internal processing to resize to their native resolution and they generally only do this in 8 bit. However, given your workflow it seems more likely these errors are being introduced by the camera's own processing.

It's a broadcast LCD monitor - Panasonic BT-LH1700WE (1280x768) hooked up via component to the cam.

Scott Jaco April 28th, 2007 03:50 PM

Try turning the detail setting to "minimum", having it set to normal or above creates alot of noise in the HD modes.

John Mitchell April 29th, 2007 10:15 PM

Quote:

Originally Posted by Claude Mangold (Post 668487)
It's a broadcast LCD monitor - Panasonic BT-LH1700WE (1280x768) hooked up via component to the cam.

Did you see the stepping live or off tape? If you saw it live the stepping is almost certainly due to the camera's processing, if you see it off tape then it could be conversions the signal is going through. If you saw it in the native .m2t file on a pc monitor displaying millions of colours, that would confirm that it is due to the cameras own internal processing.


All times are GMT -6. The time now is 08:30 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2025 The Digital Video Information Network