I am concerned about picture 'judder' and 'flicker' in some of my videos when viewed on TV, and will try to explain what I am seeing against what I would like to see.
My absolute goal is to safeguard my video work against the varying possibilities of TV types owned by clients
There are 2 main issues:-
1] Picture juddering while camera panning - specifically noticable when panning at 'mid-speed' around a background [indoor or outdoor] with no moving 'subject'
2] Bright areas of picture flicker varyingly on TV screens
Here is some further information about my equipment, techniques and research I have done on the juddery panning issue:-
Camera: Canon XM2/GL2 SD PAL [25fps] Editor: Avid Liquid 7.2 Editing codec: 'DV[AVI] 25mbit 4:2:0 PAL'
Pans are executed smoothly on location, miniDV footage ingested via FireWire, editing completed, exported to MPEG-2 DVD 720x576 25fps
Now from what I have found out, the juddery panning issue on TV playback is commonplace with consumer/prosumer camcorders - a reason being differences in screen refresh rates [hz].
So perhaps this explains why video playback of my 25fps panned material on my 50hz CRT TV is just fine, but on my 60hz computer monitor it judders a bit, and on another test CRT TV which has '100hz capabilities' it is even worse.
However I would appreciate some clarity on frame rate against TV hz, and how they may clash. I know very little about refresh rates/hz, and am more confused when seeing for example on the back of my monitor: 100-240V - 50-60hz - 1.5a max. Hz in this context is related to electrical power, screen refresh rate or both?
Is it the case that whenever my 25fps PAL material is played on a TV/display with greater than 50hz, the pans are going to judder? This is alarming, given that most TVs produced now are above 50hz. Is there no 'auto-detect' on new TVs so they play 25fps video at the correct 50hz?
After seeing how my mid-paced pans turn out on some TVs, I am at the moment almost eliminating mid-paced pans from my work in disgust - allowing only very slow or 'active' pans [i.e. with a moving subject, where any background judder is not noticeable].
On my second issue of 'flickering' on TV playback, this happens even in static shots, and is usually centred around white or brighter areas of the TV screen.
I understand a little about 'legal limits' of white and colours, and try to keep the white RBG values under 235. But still I find my films somtimes have that extra unwanted 'video' look caused by parts of the screen flickering [this is not extreme flickering likely to be very noticeable to joe public, but it is happening nontheless].
When I watch a TV programme, the picture can seem to have as much ultra-bright areas as it likes with no evidence of any flicker. I appreciate TV is shot on film or expensive HD-cameras etc etc, but is that really what it takes to be flicker-free, or am I missing something?
I try reducing my Gamma values in editing to keep those bright areas under control [windows in background etc], but can't go to far as I lose detail in people's faces in the same frame. Also I don't want to turn my whites more grey, I would just like them less 'on the surface' of the TV screen.
By that I mean, it's as if pro TV productions are behind an extra 'screen/filter' where they can be as bright as they like with no danger of flicker. How do I achieve this? What about colour Diffusion filters?
Thank you for any help and advice.