Re: [dvd::rip] Re: Deinterlacing

Robin Hill wrote:

On Mon Jul 25, 2005 at 10:58:32AM +1000, Sebastien Gerega wrote:

I am relatively new to DVD::Rip but have been extremely happy with the 
support and package as a whole. However, I have several questions 
especially in regard to deinterlacing. First of all I have some DVDs 
that I watch on my laptop, which I have come to realise are interlaced. 
This results in many horizontal lines, to the point of it being 
difficult to watch, appearing in the picture when watching the DVDs in 
linux. When I watch the movies in windows on the same laptop I do not 
get this problem. What is the reason for this? Is there a way around 
this problem?

I'd guss that your Windows player is automatically doing the
deinterlacing whereas the Linux one isn't - check the parameters for
whatever app your using, there should be options for deinterlacing.

Secondly, when ripping DVDs should one deinterlace the video? I have 
tried doing this a couple times, and apart form deinterlacing 
drastically increasing the transcoding time, I have not been completely 
happy with the results. If I really should deinterlace, are there any 
recommended filters I should apply?

From what I've read, I'd recommend to do as little irreversible change
during the ripping process as necessary.  Deinterlacing, subtitling, and
many other filters can be trivially applied during playback, allowing
them to be used only when needed.  Only if the change is too processor
intensive to be applied on playback or will be applied in any case (such
as clipping/resizing) or if you're encoding for playback on a specific
device would I recommend doing it at rip time.

HTH,
        Robin

Hi
The trouble is, encoding an interlaced movie will prevent the codec from giving good results, for while codecs are designed to analyse a picture as a whole and then compress it, they will have diffulties dealing with two "mixed" pictures. So the result won't be too good looking.
please have a look at http://www.bunkus.org/dvdripping4linux/single/index.html#ripping_interlace
I would recommend to deinterlace the movie while transcoding (no one will watch the movie interlaced anyway).
Dvdrip offers several options. It seems that "zoom to full frame" gives the best results, but is real CPU intensive (gives me about 30% of the transcoding speed I get when I do nothing to nothing, but I use it anyway because the results are really good), while "interpolate scan lines" is the fastest alternative (more than twice as fast as the previous one, I use it when ripping trailers from my dvds), but I haven't really investigated on the matter.
Have fun
Sylvain