Hi Guys, I just shot a music video, and noticed that the horizontal lines are extremely jittery - at first I thought it was a problem with interlacing but after several tests realize it wasnt. I Shot using BPress setting and love the low noise. Is there a setting that I'm missing or is it the camera?
Jittery horizontal lines
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Lenilenapi
Carbonite Member
What were your settings - be throrough. You have given no information.
from further tests I think there is something wrong in the downconversion from HD to SD. I work with AVid Xpress Pro. I watched the footage using the camera normal composite out and looks ok (although there is a very small hint of aliasing). When when I export to DV (PAL) the diagonal horizontal lines are incredibly jittery - aliasing at its best. I shot 1080p (25p). Do you guys have any suggestions about best downconverting settings?
VenezuelanD
Well-known member
Also are you doing your down converting in-camera? If you are finishing to DV-Pal why not bring in the Footage to your NLE in HD, edit it, then dump it into an SD Timeline, letting the NLE handle the downconversion (well thats how it would work in FCP, not sure on Xpress, but the process should be similar.
For your next projects, if you are going to finish in SD why not aquire in SD to begin with? You can shoot in DVC Pro 50 to a p2 card and still retain the wonderful colors of the HVX without having to worry about downconverting. There is a thread here where Barry does a test shooting 1080, 720, and DV50 and downconverts them to SD, it showed that DVC pro 50 had slightly more sharpness, mainly due to the fact that it is not being resized.
Another thing to keep in mind is that in HD mode the camera actually aquires more vertical detail than a SD interlaced television can handle. The result is that some of that detail gets stuck between two fields, causing shifting. Where are you experiencing this shift? is it some kind of thin horizontal detail that seems to shift slightly? if so I don't know what you might be able to do to get rid of it, perhaps apply a de-interlacing filter, or a flicker filter in your NLE?
For your next projects, if you are going to finish in SD why not aquire in SD to begin with? You can shoot in DVC Pro 50 to a p2 card and still retain the wonderful colors of the HVX without having to worry about downconverting. There is a thread here where Barry does a test shooting 1080, 720, and DV50 and downconverts them to SD, it showed that DVC pro 50 had slightly more sharpness, mainly due to the fact that it is not being resized.
Another thing to keep in mind is that in HD mode the camera actually aquires more vertical detail than a SD interlaced television can handle. The result is that some of that detail gets stuck between two fields, causing shifting. Where are you experiencing this shift? is it some kind of thin horizontal detail that seems to shift slightly? if so I don't know what you might be able to do to get rid of it, perhaps apply a de-interlacing filter, or a flicker filter in your NLE?
thanks Daniel, you've been a great help, I think that you hit the nail on the head with ' the horizontal detail seeming to shift slightly' - I'll do some more tests. I know its better to shoot DV50, I colour rendition is incredible compared to DV25.... but I want to shoot in HD to future proof the work I'm doing - and looks like there's a small price to pay
DavidBeier
Veteran
I've seen jittering when I downconvert to SD but nothing too big. You may just be overly sensative to it since it's your footage (I know I'm like that with a lot of stuff I shoot).