Xvid Interlace encoding problem

[MarinoIZK]

Hi,

i'm merely dying here finding a solution for a extrem quality loss when encoding a interlaced home made video with Xvid to a lower resolution.

Source specs:
Input:
65min recorded
720x576,interlaced
desired Output:
640x360 /25FPS interlaced
output video size 650mb
average bitrate 1435

Xvid settings & specs:
2pass encoding
Xvid 1.2.2

Advanced Simple @L5
H.263
B-VoPs standard
Pixel Aspect Ratio Square
Motion precision 6 ultra High,VHQ mode 1-Mode Decision

Problem description:
Annoying visible interlace line effect in 5% of the video material.

What can i do to get rid of this effect but still encode in interlace mode?

greets & thanks

[b66pak]

did you use the "-interlaced [integer]" switch (interlaced encoding (BFF:1, TFF:2) - default is 1) in the xvid line?
_

P.S. I am kidding!

Read this: http://forum.doom9.org/showthread.php?s=&threadid=74906&highlight=interlaced
_

[MarinoIZK]

Hi,

no i didn't use it.How does it works?How can i improve quality,pls?

Thanks for helping.

[thewebchat]

Generally, in video codecs, attempting to encode interlaced (weaved) images as frames will be highly inefficient, since all the combing has to be treated as detail. The "-interlaced x" switch tells Xvid to encode the even and odd lines of the frames it reads separately, which should allow you to get normal compression ratios. You must tell Xvid if your video is Bottom Field First (x = 1) or Top Field First (x = 2) so that it encodes the fields in the right order.

If you are unsure about which it is, try adding these lines to your AviSynth script:
AssumeTFF().Bob()
or
AssumeBFF().Bob()
Only one of these lines will produce smooth playback. That will allow you to know if the content is BFF or TFF.

Another thing you mentioned is that you are using Xvid to "encode to a lower resolution." If you mean that you are resizing to a lower width/height, you must first deinterlace your video, resize, and then interlace it again. You can not resize interlaced video in the vertical direction because that will smear the fields together and cause permanent jagged artifacts.

The general idea you want to apply is this:
AVISource("video.avi")
Bob()
YourFiltersHere()
BicubicResize(640,360)
SeparateFields()
SelectEvery(4,0,3)
#SelectEvery(4,1,2) <-- Use this for TFF

Also, taking the time to write readable sentences helps people take you seriously.

[MarinoIZK]

Hiya,

thanks for taking the time to explain the procedures and trechnics to get the interlaced material encoded in lower resolution.The thing is,how does this command line switch works through Tmpgenc Xpress 4?Since encoding interlaced material to progressive is not recommended,i don't have any other chance as to stick to interlaced encoding,right?

KR

[thewebchat]

2) You must encode interlaced material as interlaced.
3) I do not know what TMPGEnc has to do with Xvid. Probably, it has absolutely nothing to do with Xvid, and you are asking in the wrong place.

[Midzuki]

3) I do not know what TMPGEnc has to do with Xvid. Probably, it has absolutely nothing to do with Xvid, and you are asking in the wrong place.

At least the old TMPGEnc Plus is capable of producing AVI files by using VfW codecs such as XviD.