horizontal lines in DVD source -- how to remedy this?

MarkZ · 21st March 2011, 19:13

I have two DVD sources of television shows where many of the edges seem to be composed of horizontal lines, especially prominent during motion. It's very obnoxious. I'm curious about how I should go about encoding these files as to limit the effect of these artifacts. Should I choose positive deblocking values? Is there a lowpass filter, perhaps in avisynth, that I should enable?

For example, here's a screen shot of the VOB from VLC:

http://img820.imageshack.us/i/vlcsna...114h11m46.png/

nm · 21st March 2011, 20:00

That's combing caused by weaving the fields of an interlaced or telecined source together.

If it's a PAL DVD, it's likely interlaced or field-blended video, or less likely a case of euro-pulldown (see notes about hard-telecined NTSC below).

Interlaced video can be deinterlaced before encoding, either to 50p (full temporal resolution) or to 25p rate. Another option is to encode as interlaced and deinterlace on playback.

If it's field-blended (usually a bad conversion from an NTSC source), you could try using Srestore in AviSynth to recover the original progressive video.

If it's an NTSC DVD, the video is probably hard-telecined or interlaced. Telecine/pulldown can be recognized from the content by playing it back frame by frame. If there is a pattern of progressive frames (no combing) and then combed frames, it's likely telecined film and needs to be pulled up with an IVTC filter.

If all frames are combed, it's interlaced and can be deinterlaced or encoded in interlaced mode as in the PAL case.

Mug Funky · 24th March 2011, 02:19

i can't tell if the weirdness there is from the source or from VLC player.

the picture shows interlaced fields have been resized and thus blended together. if your source is like this, there's no fixing it - you can just blur it to make it less annoying.

nm · 24th March 2011, 10:52

Quote:

Originally Posted by Mug Funky

the picture shows interlaced fields have been resized and thus blended together. if your source is like this, there's no fixing it - you can just blur it to make it less annoying.

The sample frame has been resized vertically to 720x540 so that its aspect ratio is 4:3 with square pixels. The source video is most likely ok, and I guess it's purely interlaced since it appears to have been shot with a video camera.

21st March 2011, 19:13	#1 \| Link
MarkZ Registered User Join Date: Jan 2010 Posts: 6	horizontal lines in DVD source -- how to remedy this? I have two DVD sources of television shows where many of the edges seem to be composed of horizontal lines, especially prominent during motion. It's very obnoxious. I'm curious about how I should go about encoding these files as to limit the effect of these artifacts. Should I choose positive deblocking values? Is there a lowpass filter, perhaps in avisynth, that I should enable? For example, here's a screen shot of the VOB from VLC: http://img820.imageshack.us/i/vlcsna...114h11m46.png/

24th March 2011, 02:19	#3 \| Link
Mug Funky interlace this! Join Date: Jun 2003 Location: i'm in ur transfers, addin noise Posts: 4,555	i can't tell if the weirdness there is from the source or from VLC player. the picture shows interlaced fields have been resized and thus blended together. if your source is like this, there's no fixing it - you can just blur it to make it less annoying. __________________ sucking the life out of your videos since 2004

21st March 2011, 20:00	#2 \| Link
nm Registered User Join Date: Mar 2005 Location: Finland Posts: 2,641	That's combing caused by weaving the fields of an interlaced or telecined source together. If it's a PAL DVD, it's likely interlaced or field-blended video, or less likely a case of euro-pulldown (see notes about hard-telecined NTSC below). Interlaced video can be deinterlaced before encoding, either to 50p (full temporal resolution) or to 25p rate. Another option is to encode as interlaced and deinterlace on playback. If it's field-blended (usually a bad conversion from an NTSC source), you could try using Srestore in AviSynth to recover the original progressive video. If it's an NTSC DVD, the video is probably hard-telecined or interlaced. Telecine/pulldown can be recognized from the content by playing it back frame by frame. If there is a pattern of progressive frames (no combing) and then combed frames, it's likely telecined film and needs to be pulled up with an IVTC filter. If all frames are combed, it's interlaced and can be deinterlaced or encoded in interlaced mode as in the PAL case.