Strange artifatcs/lines in an exported video. at DVinfo.net

Alas Eastanwick · May 16th, 2008, 06:18 AM

Hi guys, this is may very first post and I feel I just might botch it a bit but all the same I have to try and ask you a question regardless of maybe posting in the wrong thread.

What are those lines on any moving object I film and try to import, in this case the lines on the edge of the fridge and along the body of the man on the screen?

http://img369.imageshack.us/my.php?i...p136215gk2.png
Now, I'm sorry but I can't seem to make the image open up in the thread to you're going to have to open it, please that is.

Take in to account that it doesn't appear if I use other viewing software. This screenshot was taken of VLC media player, and when I play the file on windows media player it's alright, though it sometimes plays real slow if I use other exporting options.

The lines are there when I use the Premiere capture tool ( I don't use any other editing software), but when i edit the file in Premiere it's alright. So when i export the file it almost always ends up like this. I've managed to find a exporting option which fixes this (only on VLC media player though) but I have to know what the problem is so I can learn to go around it.

I'm using Premiere CS3 with the Canon XH/a1. This was shot on HD on 50i fps on 16:9.

Thanks in advance.

Edward Carlson · May 16th, 2008, 07:41 AM

Those are interlace lines. Because you are viewing this on a computer monitor (which isn't interlaced) you see these lines. On a TV, which is interlaced, they will not be there. In VLC you can change the de-interlacing by going to Video > Deinterlace > Blend. This blends the two fields together, giving a softer overall image, but eliminates the lines. I know in FCP the interlace lines are only visible when the video is at 100%. Any more or less will deinterlace the video. You said you shot at 50i. The i in 50i stands for interlaced (as opposed to p for progressive.)

Alas Eastanwick · May 16th, 2008, 10:06 AM

Well that's great, I thought it was something I did. Thank you!

Bob Schneider · May 16th, 2008, 06:54 PM

Edward,

That is interesting. This is the same problem that I am having which I describe in the thread titled "CS3 Monitor Quality Issues" which is currently at the top of this same Premeire section. I am using Premiere 3 with SD video and I get similar artifacts in the source view as well as the program view inside Premiere. Any advice for me? If you have a few minutes, read that thread.

Thanks

Edward Carlson · May 16th, 2008, 08:40 PM

There's no problem here, per se. This is how interlaced video is displayed on a non-interlaced monitor. Perhaps some background would be helpful: Video is shot at 60 interlaced frames per second (30 full frames.) Because the power cycles at 60 Hz in the US, 60 makes sense for CRT televisions. Every other line of the frame is drawn (even) then the remaining lines are drawn (odd.) This happens 60 times a second, for 30 full frame drawings per second, thats where 30i comes from (also 50i, just a different rate for PAL I believe.) In frames where there is fast motion, the two fields (even and odd) differ enough that when viewing the video on a non-interlaced monitor, you can see the two different fields separated. When the video is shown on a TV or other interlaced monitor, these lines will be gone. If you video is for web delivery, you can de-interlace the video. This blends the two fields together, creating a less sharp image, but also one without interlace lines.
I have not used Premiere, so I don't know here the settings would be, or if they exist, if you are having interlacing-related difficulties.

May 16th, 2008, 06:18 AM	#1
Alas Eastanwick New Boot Join Date: May 2008 Location: Zagreb, Croatia Posts: 7	Strange artifatcs/lines in an exported video. Hi guys, this is may very first post and I feel I just might botch it a bit but all the same I have to try and ask you a question regardless of maybe posting in the wrong thread. What are those lines on any moving object I film and try to import, in this case the lines on the edge of the fridge and along the body of the man on the screen? http://img369.imageshack.us/my.php?i...p136215gk2.png Now, I'm sorry but I can't seem to make the image open up in the thread to you're going to have to open it, please that is. Take in to account that it doesn't appear if I use other viewing software. This screenshot was taken of VLC media player, and when I play the file on windows media player it's alright, though it sometimes plays real slow if I use other exporting options. The lines are there when I use the Premiere capture tool ( I don't use any other editing software), but when i edit the file in Premiere it's alright. So when i export the file it almost always ends up like this. I've managed to find a exporting option which fixes this (only on VLC media player though) but I have to know what the problem is so I can learn to go around it. I'm using Premiere CS3 with the Canon XH/a1. This was shot on HD on 50i fps on 16:9. Thanks in advance. Last edited by Alas Eastanwick; May 16th, 2008 at 06:37 AM. Reason: Information I missed out.

May 16th, 2008, 07:41 AM	#2
Edward Carlson Major Player Join Date: Mar 2007 Location: North Hollywood, CA, United States Posts: 807	Those are interlace lines. Because you are viewing this on a computer monitor (which isn't interlaced) you see these lines. On a TV, which is interlaced, they will not be there. In VLC you can change the de-interlacing by going to Video > Deinterlace > Blend. This blends the two fields together, giving a softer overall image, but eliminates the lines. I know in FCP the interlace lines are only visible when the video is at 100%. Any more or less will deinterlace the video. You said you shot at 50i. The i in 50i stands for interlaced (as opposed to p for progressive.)

May 16th, 2008, 10:06 AM	#3
Alas Eastanwick New Boot Join Date: May 2008 Location: Zagreb, Croatia Posts: 7	Well that's great, I thought it was something I did. Thank you!

May 16th, 2008, 06:54 PM	#4
Bob Schneider Regular Crew Join Date: Aug 2003 Location: Chicago area Posts: 98	Edward, That is interesting. This is the same problem that I am having which I describe in the thread titled "CS3 Monitor Quality Issues" which is currently at the top of this same Premeire section. I am using Premiere 3 with SD video and I get similar artifacts in the source view as well as the program view inside Premiere. Any advice for me? If you have a few minutes, read that thread. Thanks

May 16th, 2008, 08:40 PM	#5
Edward Carlson Major Player Join Date: Mar 2007 Location: North Hollywood, CA, United States Posts: 807	There's no problem here, per se. This is how interlaced video is displayed on a non-interlaced monitor. Perhaps some background would be helpful: Video is shot at 60 interlaced frames per second (30 full frames.) Because the power cycles at 60 Hz in the US, 60 makes sense for CRT televisions. Every other line of the frame is drawn (even) then the remaining lines are drawn (odd.) This happens 60 times a second, for 30 full frame drawings per second, thats where 30i comes from (also 50i, just a different rate for PAL I believe.) In frames where there is fast motion, the two fields (even and odd) differ enough that when viewing the video on a non-interlaced monitor, you can see the two different fields separated. When the video is shown on a TV or other interlaced monitor, these lines will be gone. If you video is for web delivery, you can de-interlace the video. This blends the two fields together, creating a less sharp image, but also one without interlace lines. I have not used Premiere, so I don't know here the settings would be, or if they exist, if you are having interlacing-related difficulties.