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Jagged Lines

Tags:
  • Tuner Cards
  • DVD
  • Graphics
Last response: in Graphics Cards
September 24, 2004 7:31:31 PM

Archived from groups: rec.video.desktop (More info?)

Ive been lurking and posting here for a few weeks and finally took my
first stab at creating a DVD. Im using Nero Express which seems
pretty easy to use. Im very happy with the process but the final
result was a tad less than what I thought it would be. I captured the
DV through a firewire (400) connection and captured it in DV Type 1
format.

On my DVD, there seems to be jagged lines between objects of different
colors. The jagged lines are most noticable between white and any
darker color. Is there something I can do to make the DVD sharper?
Overall the quality is good and the jagged lines appear more
pronounced while the object is moving.

Thanks for any help.

J

More about : jagged lines

Anonymous
September 25, 2004 2:57:37 AM

Archived from groups: rec.video.desktop (More info?)

"J" <Majicrat@yahoo.com> wrote in message
news:a6dc75a8.0409241431.79c22e17@posting.google.com...
> Ive been lurking and posting here for a few weeks and finally took my
> first stab at creating a DVD. Im using Nero Express which seems
> pretty easy to use. Im very happy with the process but the final
> result was a tad less than what I thought it would be. I captured the
> DV through a firewire (400) connection and captured it in DV Type 1
> format.
>
> On my DVD, there seems to be jagged lines between objects of different
> colors. The jagged lines are most noticable between white and any
> darker color. Is there something I can do to make the DVD sharper?
> Overall the quality is good and the jagged lines appear more
> pronounced while the object is moving.
>
> Thanks for any help.
>
Are you seeing these lines while watching on the computer or on a TV?

If you are seeing them on the computer, but not on TV, then you are
seeing what is called interlacing.

In an effort to reduce the flicker of a TV picture they adopted interlacing.
Simply put, it divides each frame into 2 fields. One field contains the
"odd lines" and the other contains the even lines. At the time television
was being designed, there was no way to store a full frame image (or
even a field for that matter).As the electron beam scanned in every other
line,
the TVs at home scanned out in perfect sync. What you saw on TV was
truly live, right down to the level of each scanline. This caused the
picture to
be perceived as a solid image, because a half picture gets scanned out 60
times a second (50 times a second in PAL).

So, what you are seeing as jagged lines is the difference between the
position
of a moving object in 2 different positions 1/60th of a second apart. The
side
effect of interlaced scanning is far smoother motion on the TV,
unfortunately,
the side effect on a computer screen is those jagged lines. A computer shows
you both fields at once, instead of sequentially as on a TV. If you intend
to
mostly view your video on a computer then you could use a deinterlacer to
remove these motion artifacts. A simple deinterlaceing application will just
remove half of the scanlines thus reducing the resolution by half. A smart
deinterlacer will keep all of the resolution in portions of the picture that
don't
have motion, and reduce the resolution only in areas where there is motion.

David
Anonymous
September 25, 2004 3:06:19 AM

Archived from groups: rec.video.desktop (More info?)

The DVD compressor built into Nero maybe isn't doing a good job, creating
compression artifacts around the edge of objects. You have to expect some of
this because the data rate of DVD is quite a bit lower than mini-DV. So you will
lose quality.

I like the results I get with a cheapo program called Ulead Movie Maker 3
because I can set the compression level to variable and max the quality
settings. This takes more time to render the DVD files, but the quality is
pretty good. The one time I tried an earlier version of Nero to do the
compressing, I thought the results were borderline terrible, with all kinds of
MPEG artifacts around the edges of moving objects.

"J" <Majicrat@yahoo.com> wrote in message
news:a6dc75a8.0409241431.79c22e17@posting.google.com...
> Ive been lurking and posting here for a few weeks and finally took my
> first stab at creating a DVD. Im using Nero Express which seems
> pretty easy to use. Im very happy with the process but the final
> result was a tad less than what I thought it would be. I captured the
> DV through a firewire (400) connection and captured it in DV Type 1
> format.
>
> On my DVD, there seems to be jagged lines between objects of different
> colors. The jagged lines are most noticable between white and any
> darker color. Is there something I can do to make the DVD sharper?
> Overall the quality is good and the jagged lines appear more
> pronounced while the object is moving.
>
> Thanks for any help.
>
> J
Anonymous
September 25, 2004 5:33:31 AM

Archived from groups: rec.video.desktop (More info?)

"david.mccall" <david.mccallUNDERLINE@comcast.net> wrote:

>"J" <Majicrat@yahoo.com> wrote in message
>news:a6dc75a8.0409241431.79c22e17@posting.google.com...
>>
>> On my DVD, there seems to be jagged lines between objects of different
>> colors. The jagged lines are most noticable between white and any
>> darker color. Is there something I can do to make the DVD sharper?
>> Overall the quality is good and the jagged lines appear more
>> pronounced while the object is moving.
>>
>Are you seeing these lines while watching on the computer or on a TV?
>
>If you are seeing them on the computer, but not on TV, then you are
>seeing what is called interlacing.

If he's seeing them on the TV, then the field order may have been set
incorrectly during MPEG encoding. DV video is supposed to be bottom
(B) field first.