Degraded Image Quality in AE

[Ken Evans]

Just wanted to add something else.

I’m now trying other machines to see how they behave and found this:

You’ll see on the left the clip viewer in AE and on the right the QT window showing the same frame. There’s a real gamma/chroma difference between the two. This isn’t normal is it?

When adding this to the timeline there was no degrading of the image but it did mirror the left hand window and didn’t look half as crisp as the right.

Very odd!

[John Hammond]

viewing SD widescreen footage and a SD comp with wide pixels (1.42) will always make footage look blocky. If you press the pixel aspect ratio correction button it shows u how it really looks.

[Ken Evans]

I’m aware that the pixel aspect ratio button corrects the vertical blocks but it’s not fixing the general degrading of the picture.

Check the reference shots and you’ll see. The little cardboard guy with the camera has lost all definition in his line detail, it’s become a broken line. You’ll see on the original that the lines are fine. In AE, with pixel ration changed back to it’s anamorphic state, the lines are still broken.

This also doesn’t explain the problems with my subsequent post and how AE has again degraded the original after import.

[John Hammond]

hmm I’m not sure about the degradation.. could be a codec issue? I know that when I look at my footage through Quicktime it often looks bad (I use PC and render to uncompresed .AVI usually, before encoding to MPEG, or whatever)

As for the mismatch in colour / gamma.. It could be to do with the colour profile being used on each machine.. I only say that because the other day I looked at one of my videos through VLC (a free video player) and my whites had turned greenish! It was because VLC ignores my color profile that I created with calibration hardware..

[Ken Evans]

Hi Thanks for the responses.
The footage is straight out of the camera.

I guess that each app could be handling the material differently but I’ve never seen quite such a shift of properties as the latter shots of the young lad.

Back to the original, it appears that we are only seeing a single field of what has been shot, which again is odd as the material was shot in progressive scan mode. Can AE render multiple fields for preview?

I’m totally stumped and have also stumped another 4 AE forums.

I’ll let you know if I fix it. I should also point out that in Final Cut Pro I get the same effect when the clip is paused but then it comes to life on playback. In Quicktime the clip looks great whether paused or played.

[Ken Evans]

Have a look at the images linked:

https://www.mediafire.com/?n2ztmeknd2x

Picture 1 is a grab of the 3 pictures.

Top left is the preview from the AE project window.
Top right is the viewer in AE
Bottom is the QT movie

You can clearly see in the 2 AE clips the banding, particularly on the creatures ‘crest’ that’s in the cage. The banding affects the entire image

The bottom clip shows how it SHOULD look, a nice crisp shot with no banding direct from Quicktime.

I’ve posted this issue of 4 AE forums and no one has been able to provide an answer to it.

The other pictures are of what goes on when trying to key these images. The banding makes it nearly impossible to get a clean key. however as mentioned, in Final Cut Pro, the images are both crisp and key out fine without any banding.

The reason I’m using AE is because there is other work to be done once keyed and the Key light plugin does the best job on DV material.

I’d love to hear from you!

https://www.mediafire.com/?2yt2jinhkwq
https://www.mediafire.com/?mzmnmdiozlt
https://www.mediafire.com/?k5ztadjzkmj

[Ken Evans]

I think I may have found out the problem here.

The problem areas are with the high contrast blue and red-and other areas but blue and red show the most degradation. Obviously, DV being 4:1:1 (Panasonic DVCPro, NOT the 4:2:0 of DV PAL) there is a lot of colour information missing and the blue channel always takes the heaviest losses on the DVCPro format.

The reason we’ve never seen this before is because we’ve always used the HVX cameras for either DVCPro 50 or DVCPro HD in this particular setup. In normal DV mode we almost always use our DVX100’s which do have the different colour sampling and manage to smooth over this high contrast blue and red issue because of the sampling method and other factors like lesser quality optics, CCD blocks etc.

So, by colour smoothing the material, something which QT player appears to do by default (I’m awaiting a reply from my engineer friend at Apple to confirm this) the steppy vertical lines disappear and everything is back to normal. It doesn’t matter if the material is stretched out way beyond it’s original dimensions, with the colour smoothed it fixes the banding on the high contrast red and blue areas.

So the conclusion is format/codec, using a blue screen when a green one is far better suited to DV and subject material all conspired to produce the problem.