[mythtv-users] Re: Hardware MPEG2 vs bt878

[Derek Meek]

so... screenshots anyone?

On 9/29/05, Baudouin, Andrew <andrew.baudsouin at awc-inc.com> wrote:
> See, your problem is that you assumed I was talking about bt87x in
> particular.  I said "a framegrabber".
>
> :)
>
>
> Are the Hokies actually going to come into LSU in 2007?  Or is
> Back-Out-Beamer going to wuss out again? :)
>
>
> -----Original Message-----
> From: Cory Papenfuss [mailto:papenfuss at juneau.me.vt.edu]
> Sent: Thursday, September 29, 2005 4:21 PM
> To: Discussion about mythtv
> Subject: RE: [mythtv-users] Re: Hardware MPEG2 vs bt878
>
> On Thu, 29 Sep 2005, Baudouin, Andrew wrote:
>
> > Actually, believe it or not...
> >
> > All things equal a framegrabber will result in superior quality on-disk.
> > The problem lies with the quality of the tuner on the cheap
> framegrabbers.
> > It's clearly below that of the more expensive hardware cards.
> >
> > To preserve quality ideally you'd like to have the raw video on disk and
> > compress it as you see fit rather than go straight into MPEG2.
> >
> >
>  	"Everything" is not equal in this case.  The BT878 chip has
> inherently lower resolution for composite inputs (e.g. anything coming in
> via the tuner) than the SAA7115 or the CX--- that the PVR-[123]50's use.
> That has a much larger effect than the MPEG compression artifacts.  The
> MPEG artifacts can be effectively eliminated by cranking up the bitrate to
> lots... it'll still be more space efficient than RAW captures.
>
>  	Since he's planning to use svid in an presumably an external
> demodulator, the difference may be less.  The lower resolution is the lack
> of comb filters... that's not used for s-vid inputs.  There are still some
> (optional) filters in the signal flow path.  One would have to ensure they
> were off.   The CX--- chip still has 10bit vs. 8bit for the BT878.
>
> -Cory
>
> --
>
> *************************************************************************
> * Cory Papenfuss                                                        *
> * Electrical Engineering candidate Ph.D. graduate student               *
> * Virginia Polytechnic Institute and State University                   *
> *************************************************************************
>
>
>