Yesterday I looked through all of the footage I had taken, and put together a cut of the shots I wanted to use. I had about 10 minutes worth of footage to look through and cut down to 30 seconds of footage that I will use in Adobe After Effects to create my visual effects piece. To do this I used Adobe Premiere Pro. I imported the clips that I wanted to use in my piece, and cut them to appropriate lengths before ordering them to create a chronological sequence.

Here is the full sequence in order:

As well as rendering the full sequence, I also decided that it would be wise to take every shot individually and render them into their own .mov files. The reason I did this is so that when I come to editing the final piece in After Effects, to keep the composition tidy and easier to manage, I want to be able to pre-comp every shot on its own. I wouldn’t be able to do this on After Effects if I used the complete sequence and it would make life harder over the course of editing. Plus it means that if the green is slightly different on the shots, I can use the Keylight plugin on each shot instead of having to have multiple effects on the same composition. This should save me a lot of time and hard work!

Problems

In Premiere Pro, I previewed the sequence before I rendered it, and it was absolutely fine. No problems whatsoever. However, when I imported my footage into After Effects I realised that when I had rendered the footage on Premiere Pro, I had rendered it in the wrong format. I shot the footage in 1080p24 and accidentally rendered the footage using 1080i24.

This was the result:

lines 1

This happens every 3-4 frames, particularly during motion intensive shots.

lines 2

I did some research and discovered that the problem was to do with interlacing. I discovered that shooting in one format and rendering in another would come up with this problem, but I hadn’t found any footage that confirmed that this was exactly what was happening in my render. I refined my search, searching “1080p footage rendered to 1080i horizontal lines problem” ,and found this thread which confirmed my diagnosis:

http://hupitgaming.com/forum/16-help/276484-interlace-problems-when-rendering-hd-pvr-footage-in-sony-vegas

The video in this thread displayed exactly the same problem that I was having. This means that pretty much all of my work yesterday was for nothing. Well, not quite. Luckily I saved the Premiere Pro project file! I just need to re-render the footage using the correct settings and the problem (hopefully) will be solved! While i’m at it, I am going to cut a couple more of the shots down as I feel that a few shots linger too long and remove any suspense or action implied by the script. I’ll also round it off at 30 seconds rather than 35.

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