[mythtv-users] Video Quality

Shay - MythTV mythtv at highstyleweb.com
Thu Mar 11 15:27:23 EST 2004


At 01:35 PM 3/11/2004, you wrote:
>On Thu, Mar 11, 2004 at 12:53:21PM -0600, Shay - MythTV wrote:
> > At 11:04 AM 3/11/2004, you wrote:
> > >And here I was hoping this was a discussion of the best recording or
> > >transcoding settings...
> > >
> > >On Thu, 2004-03-11 at 11:25, Adrian Byng-Clarke wrote:
> > >> How much of a video quality upgrade does one get by moving from a basic
> > >card
> > >> like that to one of the PVR cards like the Hauppauge PVR 350. For 
> example
> > >> does the on board Mpeg 2 make that much of a difference? After all
> > >can't one
> > >> just compress the signal after capture (sacrificing time and HD 
> space for
> > >> $$$) or is there more to it than that.
> > >
> > >The advantage of a card like my PVR-250 is that it encodes in hardware
> > >so the CPU only has to deal with encoded video.  That's far less data.
> > >With uncompressed video, your CPU is swamped with data.  If your CPU is
> > >fast enough and your memory and bus bandwidth is high enough, you can
> > >still get a perfect recording without hardware compression, but anything
> > >that causes the CPU to get distracted will result in a glitch in the
> > >recording.
> > >
> > >> Perhaps people could post samples of video captured. I don't want to get
> > >> anyone in trouble - maybe they could just post something off of 
> public TV
> > >> etc... I just want to get a sense of the quality. For example Tivo's 
> high
> > >> quality setting looks to my eye exactly like the broadcast signal 
> coming
> > >in
> > >> - there are no artifacts on a TV.  Is this possible with a Linux PVR 
> rig?
> > >> Also is it only possible with the higher end capture cards?
> > >
> > >With a PVR-250, my first recording looked every bit as good as my
> > >ReplayTV on high quality.  I intend to play with the recording profiles
> > >a bit to see what I really want.  My guess is that I'll record at a
> > >fairly high quality and then transcode things offline if we're keeping
> > >them around for a while.
> > >
> > >But yes, Myth can provide results equivalent in quality to a TiVo with
> > >hardware encoding (or with ATSC broadcasts, which are already encoded,
> > >but that's another issue).
> >
> > Really?  I have yet to get my MythTV to record as well as my TiVo.  I have
> > a 250 and it just doesn't compare.  Its nice and all, but when things move
> > you see glitches.. artifacts.. I don't know the word for it.. its just not
> > smooth..
>
>
>What are you viewing it on?  A monitor?  A TV?  If the former then that's 
>because
>it's interlaced video.  If the latter, then what sort of TVOUT are you using?
>I have a 350 and I, for one, can not tell the difference between the original
>broadcast and recorded programs (I've tested side-by-side Myth vs. DirecTV 
>alone).
>I don't see how TiVo can beat that.

57" HDTV via s-video.  TiVo is via RCA.  Maybe its the 250?  It's not my 
graphics card because DivX movies are perfect.

-Shay






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