Black pixel row at the bottom

[Ruzo]

Hi,
I am not a pro so I'm just reporting something that came to my attention. After using cgipro's script to fix the stair-stepping on a file, I used InstantHD to convert it to 1080p and that's when I saw a grayed line across the bottom:




After further investigation, I realized that it happened because of a row of black pixels at the bottom which is also found in the original footage. InstantHD must be trying to blend the doubled black row into the expanded image, creating the grayed row. If I crop this last row out, it gives me a clean image at 1080.

So, my D90 seems to produce a 1280x719 image plus a row of black pixels at the bottom. Here is a frame over a blue background:




I was thinking that cgipro's script (and other Stair-Stepping removal scripts) could be modified to include a crop of this last row in order to have a clean footage. I'm not sure how much the ratio becomes an issue but I could not see a real difference when going from 1280x800 to 1920x1080 compared to 1280x801. However, if there is a way to keep the ratio intact, I would prefer it.

If I knew a bit about AviSynth script syntax, I'm sure it would be as simple as adding one line of code.

I hope I'm not seen as "anal" after this

[Andrew Brinkhaus]

Interesting. I am not seeing any affect of this in my footage.

[NJ3118]

isnt the footage already in HD? and cant you just export as 1920X1080 with an editing program? why the need for InstantHD?

[Ruzo]

isnt the footage already in HD? and cant you just export as 1920X1080 with an editing program? why the need for InstantHD?

The footage is at 1280x720. The Stair-Stepping removal method increases the size to 1280X801. Instead of resizing to 1280x720, I wanted to go to 1920x1080. With InstantHD, it's supposed to give better results than just a direct export. Also, the instantHD process was just something that brought my attention to the strange black row. It wasn't my main point.

[Ruzo]

Interesting. I am not seeing any affect of this in my footage.

How did you check?

[Ruzo]

Hmm...Is it just from my camera?

[Ruzo]

Is it the title or lack of traffic during the holidays?

[Car3o]

don't think people really know what's going on with your vid to be honest. i don't upscale so i can't compare.

[Ruzo]

okay, maybe I confused everyone with too much information at one time. It's just that my whole experience brought me to discover the fact that the last bottom row of pixels of my D90 movies is totally black.
The up-scaling artifact is caused by this black row which is in all the original movie files.

Could anyone check one of their D90 files to see if the last bottom row is black?

Thanks.

[Car3o]

with stair step fix, or without?