[mythtv-users] Video Quality
cedelis at uillinois.edu
Thu Mar 11 17:10:52 EST 2004
On Thu, Mar 11, 2004 at 02:27:23PM -0600, Shay - MythTV wrote:
> 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
> >> >card
> >> >> like that to one of the PVR cards like the Hauppauge PVR 350. For
> >> >> 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
> >> >> 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
> >> >> quality setting looks to my eye exactly like the broadcast signal
> >> >in
> >> >> - there are no artifacts on a TV. Is this possible with a Linux PVR
> >> >> 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
> >> a 250 and it just doesn't compare. Its nice and all, but when things
> >> you see glitches.. artifacts.. I don't know the word for it.. its just
> >> smooth..
> >What are you viewing it on? A monitor? A TV? If the former then that's
> >it's interlaced video. If the latter, then what sort of TVOUT are you
> >I have a 350 and I, for one, can not tell the difference between the
> >broadcast and recorded programs (I've tested side-by-side Myth vs. DirecTV
> >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.
I dunno. Maybe your TV expects progressive scan video (non interlaced).
You might want to try deinterlacing the picture. I believe this is a
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