Help! Pink line in export!

[Bob Gruen]

I'm in the middle of doing a film-out test of my workflow and I've run into a big problem. There is a pink line in every three frames at the bottom of the image. It is on the very bottom on the left side then jumps up a pixel or two on the right. It appears on NLE playback and on exported material, but not in frame by frame inspection in Avid.

My workflow is as follows:

• HVX set to 1080i / 24PA
• Recording in DV Rack making QT Avid files (which cannot be viewed with QT for some reason)
• Import into Avid, DNxHD 175
• Export as MOV encoded with DNxHD 175, 115, or same as source

I think I may have seen this line twice before. First, when the camera is set up to 1080i / 24PA it flashes the same / similar line on my 1080i television. When thoff did a test pulldown removal for me using the Serious Magic batch converter the pink line disappeared. So I assumed it was an artifact in the garbage frame that the Advanced Pulldown creates. Next when I bought DVRack and did not update it it had a bug that removed the wrong frame during advanced pulldown removal. The line showed up in this situation right before the improperly removed frame. I thougt that this verified my theory about it being part of the garbage frame, so I didn't worry about it.

So now that I am ready to send a file off to be printed the line has reappeared, maybe... I'm not sure if it is the same line or if it is a similar looking error in the data stream that Avid can correct on scene by scene inspection but not 'on the fly'... Now I am wondering if there is something wrong with my camera, although like I stated earlier the flaw does not show up when I view the footage frame by frame.

Any thoughts or ideas? I want to get this exported to send it to DVFilm for a test printing. Any help or suggestions would be appreciated.

Bob

 

[cbrougham]

While I don't really know what the artifact is, or how to cure it necessarily, I might be able to help you diagnose it further. You said that you see it on playback out of the Avid, and on exported files, but I'm assuming that when you step through your clip/sequence, you don't see it... correct? If so, it might actually be appearing in Avid, but the way that you step through the clip cause you not to see it.

Avid (I believe) shows only the lower field of each frame as you step through a clip. However, there is also the ability to step through a clip or sequence by fields, instead of just frames. I don't believe it's mapped by default, but if you go into the Command Palette, you'll find it. You can also enter effects mode on a clip, and step through by fields that way (you'll see frame count indicated as x.1 or x.2 to indicate which field you're viewing).

While this obviously doesn't cure the problem you're having, it should help a little bit in diagnosing where the problem lies. Hope that helps somewhat... maybe!

 

[Bob Gruen]

C.B.

Thanks for the reply.

One of the things that DV Rack does for me is to merge the fields into progressive frames and remove the 'garbage' frame from the Advanced Pulldown. Unless I misunderstand, I am in a 24P timeline and I am not working with fields at all.

Bob