CCE strange interlacing problem

[anacierdem]

I've captured an interlaced PAL cassette footage (Old VHS cassette) with no problems. The resolution is 720x576, the first capture is compressed using huffyuv, the frame rate is 25 and the audio is mono an usual. The footage is about 1 hour 6 minutes long but the avi is a little bit longer. I'm using avisynth to adjust the avi file here is the script even though it has nothing to do with the strange problem;

clip=AVISource("I:\Captured\orjinal\ece.avi" , False)
aud=WAVSource("I:\Captured\orjinal\ece.avi")
AssumeFieldBased (clip)
AudioDub(clip,aud)
ResampleAudio(48000)
Trim (80,48653)

(without the re-dub, CCE was loosing the video timings in MP VBR mode)

I'm using CCE SP 2.7 to encode. Encoding in MP VBR mode with a 4:3 aspect ratio, 8520 kbit average, 5500 min and 9080 max bitrates. In the picture window all the filters are disabled and I'm choosing alternate block scan order since the material is interlaced. The problem is not related to the field order everything is set appropriately and tested.



The problem is that when I encode by not checking the "progressive frame" checkbox in the picture menu as advised in the manual for interlaced material, I get some unusual interlacing artifacts. And soon I realized that the video is double interlaced!
I mean when the picture is divided into fields the two fields are also interlaced. Some inter field arrangement? I have no idea how CCE merges frames and generate a 4 field image. Thought you guys may have some idea on what's goin on?! (check the pictures below)

When the progressive frame checkbox is unchecked, the output stream seems interlaced but these artifacts are not present. So what the heck is CCE doing? Should i follow the manual for better quality? I don't think the first result have much more quality... When played on a DVD player, both scenarios give almost the same result. DVD player's or the LCD TV's deinterlacer is handling the situation. Only when paused the stream with the progressive frame checked the interlace lines become visible on the DVD player.

Some pictures may help you better understand the situation;

http://img375.imageshack.us/img375/5725/testkh.png
This is the original avi.

http://img843.imageshack.us/img843/346/retest.png
This is the encoded frame with progressive frame unchecked. You can see the weird artifacts. (sorry for the different proportion but it gives the idea)

http://img547.imageshack.us/img547/4000/testprog.png
This is the encoded frame with progressive frame checked.
(seems very much like the original)

Both encoded frames have alternate block order selected.

http://img821.imageshack.us/img821/9305/even.png
The odd fields from the artifacted encode. (still seems interlaced, fields duplicated)

http://img829.imageshack.us/img829/1840/odd.png
The even fields from the artifacted encode. (still seems interlaced, fields duplicated)

I thought that the "sub-sub" fields have an inaproppriate field order but I could not verify...
Also keeping in mind that there is not any pulldown problem,
Is processing with progressive frame checkbox safe?

[anacierdem]

I think the problem is solved, I played the mpeg 2 file in a different program and it seems normal...
Anyway why it is happening on VLC player?

[Ghitulescu]

It cannot be double interlaced :)

What you see is generally known as chroma upsampling bug.

And you can't judge a video using stills, not only because what we have is a PC monitor and all PC monitors are progressive thus the software must deinterlace (bad or good) the frame.

And don't judge a video on a PC screen as explained before. Burn a DVDRW and check it on a real TV (CRT preferably).

[anacierdem]

There weren't any active deinterlacing filter.. but sorry for the post anyway...