Cam vs. Canopus

bdunn wrote on 8/31/2002, 6:07 PM
Hi,

I've been using my Sony D8 camcorder as my A/D converter.
I am noticing artifacts in shadow areas of rendered MPEG2s.
I can mask it by decreasing the brightness and increasing the contast
per a post by wvg.

In a another post, Gammaburst mentioned that the Sony's produce an
IRE 0 instead of an IRE 7.5. Could this IRE difference be causing
changes in the brightness and contrast resulting in the 'moving shadows'?

So, I'm curious .. has anyone switched from using their camcorder
to using a Canopus ADVC-100 and seen any improvement in the resulting
captures?

Thanks in advance for any input.
bd

Comments

wcoxe1 wrote on 8/31/2002, 8:08 PM
Changing to IRE 0 instead of an IRE of 7.5 would violate all the definitions of what Sony is supposed to be building. You can pretty well be that they did not.
bdunn wrote on 9/1/2002, 9:18 AM
wcoxe1,
Thanks for the response. Can I take it that your feeling is that my problem
is something other than my capture device?

I do know from testing that it is not a field order or bitrate issue. Also, I did see an improvement in captures by removing a cheap S-Video switch and connecting directly from the source to the camera. However, this did not provide a complete cure but it was a considerable improvement. Is it possible that I'm approaching the
limits of what is achievable?
Thanks again,
bd
GaryAshorn wrote on 9/1/2002, 10:21 AM
Japanese camera or video systems are built on 0 IRE. Sony and others are all 0 IRE. The blurring of consumer to Prosumer to professional you will find options on some menus that allow you to set that. But the digital 8 will be 0 IRE.

Gary Ashorn, PE
bdunn wrote on 9/1/2002, 12:04 PM
Gary,
Thanks for the info.
Just being a 'weekend warrior' I'm not sure I understand the ramifications of the
0 vs. 7.5 other than it affects the Black Level (and it is in the dark and/or shadow areas that I see the problem). Could this deviation produce changes in brightness and contrast of the rendered MPEG2?
As always, many thanks to this great forum.
bd
GaryAshorn wrote on 9/2/2002, 12:05 PM
I am not all that sure of how VV3 handles the below 7.5IRE range. SF tech will have to answer that one. I mostly edit on the VM/DPR system and use VV3 to do the heavy multilayering stuff and import it back to my editing system. But my system handles the IRE range on input and output and I can control how I want it to do that. VV3 may or may not let you do that and I have not tried to see. How MPEG2 handles it may be one thing and then of course how it is displayed is another. That are a lot of steps or gates the signal is going through. First the camera, then capture, edit, output, recorder and/or DVD, then play back system. Each may or may not handle a given circumstance differently.

Gary Ashorn, PE
bdunn wrote on 9/2/2002, 7:44 PM
Gary, many thanks for the additional info and my apologies.
I didn't mean for the questions in the last reply to seem as
though it was directed at you. Next time I'll try to remember to
split my posts between the "thank you's" and the next question.
bd

Just an fyi, the concensus over at the "Cow" seemed to be to go for the Canopus
as the other option was very long renders.
SonyDennis wrote on 9/2/2002, 8:49 PM
"Setup" (as it's called) is purely an analog issue, and therefore Vegas doesn't have to handle it. That said, Vegas can be used to correct digital media that has been captured in the incorrect mode, or with equipment whose mode can't be set, using various plug-ins (such as "Levels"). If an analog signal with setup is captured on equipment that doesn't remove setup, Vegas can darken and stretch the signal to remove the setup digitally, but if setup that didn't exist is "removed", you've lost signal, and it's too late to fix it in the digital domain, all you can do is raise the blacks back up, but you'll be missing a range of black that got clipped.
///d@