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<div><span class="gmail_quote">On 15/01/2008, <b class="gmail_sendername">Steve Peters - Priority Electronics</b> <<a href="mailto:steve@priorityelectronics.com">steve@priorityelectronics.com</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br><br>-----Original Message-----<br>From: <a href="mailto:mythtv-users-bounces@mythtv.org">mythtv-users-bounces@mythtv.org
</a><br>[mailto:<a href="mailto:mythtv-users-bounces@mythtv.org">mythtv-users-bounces@mythtv.org</a>] On Behalf Of Brian Wood<br>Sent: Tuesday, January 15, 2008 8:45 AM<br>To: Discussion about mythtv<br>Subject: Re: [mythtv-users] am i dropping frames?
<br><br><br>Steve Peters - Priority Electronics wrote:<br><br>><br>><br>><br>> That all makes perfect sense, but when I plug my cable line directly<br>> into the tv, the sports programs are great quality. Also, if I up the
<br>> pvr-500 to the max bitrate, I think that would be enough to offset<br>> this, but it doesn't. Does anyone else have this issue, or do most of<br>> you have no problem with sports?<br><br>Upping the bitrate gives diminishing returns after a certain point, see:
<br><br><a href="http://www.mediachance.com/dvdlab/tutorial/bitrate.html">http://www.mediachance.com/dvdlab/tutorial/bitrate.html</a><br><br>There are other parameters besides bitrate, in addition to resolution there<br>are a slew of parameters that can be set on the PVR's encoder, but remember
<br>that the PVR is a consumer-quality inexpensive device.<br><br>But having said that, a PVR can yield very good results. If I look carefully<br>I can see the artifacts produced by the card, but most viewers, not knowing
<br>what to look for, do not see a difference between the direct source and a<br>Myth-reproduced picture.<br><br>beww<br>_______________________________________________<br>mythtv-users mailing list<br><a href="mailto:mythtv-users@mythtv.org">
mythtv-users@mythtv.org</a><br><a href="http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users">http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users</a><br>____________________________________________________________<br>
<br><br>Beww, so are you saying that this might be normal for myth recordings? Is<br>everyone using mythtv stuck with this kind of playback problem? It's not the<br>artifacts that are the problem, it's the lack of smooth playback that is the
<br>problem. I just don't see how any sports fan could put up with this. I go to<br>other people's houses and watch sports there and I think to myself...I'd<br>better not invite them over to my place to watch sports, cause that will
<br>make my mythtv setup look really bad.<br>-Thanks<br><br><br>_______________________________________________<br>mythtv-users mailing list<br><a href="mailto:mythtv-users@mythtv.org">mythtv-users@mythtv.org</a><br><a href="http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users">
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users</a><br></blockquote></div>
<div><br>It does sound to me like you are seeing the effects of deinterlacing. Quite why bob doesn't work for you I'm not sure.</div>
<div> </div>
<div><Grandma sucking eggs warning!></div>
<div>Basically the Sports programmes are probably sent interlaced. Over here in PAL land this means that I would recieve a signal with:</div>
<div> 25 Frames per second (in NTSC land 30 FPS) each consisting of 2 fields.So I'm actually receiving 50 Fields a second.</div>
<div>
<div>Each field consists of "half" of the picture (frame) with one having the odd lines and one the even.</div>
<div>You migh think that these 2 fields make up a frame from one instant in time, but this is not usually the case (with SD anyway I don't know about HD). The second field is actually recorded by the camera slightly later than the first.
</div>
<div> </div>
<div>So effectively what you recieve is a signal that is sort of at 50Fps (in NTSC land 60Fps) giving you lovely smoooth motion...</div>
<div>When you de-interlace down to 25 FPS you lose some of that smoothness...</div></div>
<div> </div>
<div>This doesn't apply to movies shot on film as they are shot at 25Frames per second full stop. You might say that the film camera is a "progressive scan" type of device!</div>
<div></Grandma sucking eggs warning!></div>
<div> </div>
<div>So the question really is... why is bob not working correctly?</div>
<div> </div>
<div>Cheers</div>
<div> </div>
<div>Steve</div>