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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>First, sorry that my posts keep appearing
at the top and in html, I don’t know how to make MS Outlook (yuk!) do it
the normal way.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Yeah I’m recording from DVB-T, and
my card has hardware MPEG2 compression. I like Linear deinterlacing also, but
again it just doesn’t have enough fps to make snooker or tennis watchable
(for example), the inbuilt tuner in my TV gives perfect picture. I’ve yet
to get any modeline that works (my TV is an LG 37LP1D), so I’ll worry
about the framerate problem later<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>
mythtv-users-bounces@mythtv.org [mailto:mythtv-users-bounces@mythtv.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Niels Dybdahl<br>
<b><span style='font-weight:bold'>Sent:</span></b> 01 June 2006 08:31<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">Discussion
about mythtv</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [mythtv-users] Having
problems / Need info on BOB Deinterlacing</span></font><span lang=EN-US><o:p></o:p></span></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On 5/31/06, <b><span style='font-weight:bold'>James Buckley</span></b>
<<a href="mailto:james@logicland.co.uk">james@logicland.co.uk</a>> wrote:<o:p></o:p></span></font></p>
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<blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;
margin-left:4.8pt;margin-right:0cm'>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hello, I've been building my Myth box for well over 3 moths now;
everything<br>
works except for one major problem, TV playback (lol).<br>
<br>
I find that TV playback with either no deinterlacing or non BOB<br>
deinterlacing just doesn't have enough frames a second to be watchable. For <br>
example, if you compare news tickers you get on sky news or BBC news, over<br>
normal Freeview / DVB-T, they are much smoother than through MythTV. Unless<br>
I can get the tickers to be as smooth as normal TV (or very close to), I'm <br>
gonna end up scrapping this project, something I really don't want to do.<br>
<br>
My setup is as follows, I have a Myth box running latest SVN build,<br>
outputting over DVI (from a Nvidia 6200 chipset) direct to my LCD TV. I <br>
haven't created a custom modeline, as I can get crisp, no overscanning<br>
output, using the resolution 1360x768, progressive. Now, the solution to a<br>
low frame rate is to use BOB deinterlacing, this makes TV smooth, but has <br>
some very horrible side effects.<br>
<br>
1. The video jumps up and down, not a little bit, but really noticeably<br>
2. The OSD goes horrible, hard to describe, but you no what I'm talking<br>
about<br>
3. Any Interactive overlays, like "push the red button" are given the
same <br>
effect as 2.<br>
<br>
Certain scenes on TV go really horrible when using BOB deinterlace, for<br>
example anything with lots of horizontal lines is almost unbearable to<br>
watch, as they jump up and down, also text (as this has horizontal lines <br>
also) is jumpy, on the news tickers it jumps , and cause it's close to the<br>
edge of the ticker, it's really noticeable.<br>
<br>
I'm sure it can't just be me who can't put up with these problems, so does<br>
anyone have an idea what causes these, what can be done to minimise them, <br>
and if there are any alternatives to BOB deinterlacing, but still doubling<br>
the frame rate.<o:p></o:p></span></font></p>
</blockquote>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
I think you are running into a combination of several problems:<br>
<br>
- Bitrate. Ticker lines seem to be very hard to compress into MPEG2. So to have
soft moving ticker lines you need as high a bitrate as you can get if you
record from an analog signal. If you record from a DVB signal then you can not
do anything at that point. Having MythTV record a DVB signal should be as good
as using any other DVB receiver. <br>
<br>
- Frame rate. If the frame rates in your system do not match, then you will get
some kind of low-frequency disturbance. There are three frame-rates to
consider. You receive a signal with some framerate. In the <st1:country-region
w:st="on"><st1:place w:st="on">UK</st1:place></st1:country-region> you use
PAL-I which have 50 half-frames per second. Then your videoadapter sends the
videosignal to your monitor. If you do not modify your modeline, it will
probably send 60 or 70 full-frames per second. By deinterlacing you will
convert the 50 half-frames to either 25 full-frames or 50 full-frames per
second. Both will give some low-frequency disturbance when you output with 60
or 70 full-frames per second. You should find a better modeline. Third your
LCD-monitor has an internal refreshrate. The LCD pixels are mounted in a grid
and only one row of pixels are updated at a time. Some older monitors have a
fixed refresh rate at 60 frames per second. If that is the case, it will never
look very good, especially not if your videoboard outputs at 70 frames per
second. <br>
<br>
- Deinterlacing. Bob will make OSD and similar jump up and down. I did not like
it, so I chose the linear deinterlacing instead.<br>
<br>
Niels Dybdahl<o:p></o:p></span></font></p>
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