[mythtv-users] Changing width resolution for PVR-250/350's

[Drew Tomlinson]

On 1/18/2006 12:14 AM f-myth-users at media.mit.edu wrote:

>    > Date: Tue, 17 Jan 2006 21:27:59 -0400
>    > From: Greg Estabrooks <greg at phaze.org>
>
>    > > But I also saw a neglible change in file sizes, too.  Is this 
>    > > the expected behavior?
>
>    >  Certainly, bitrate is bitrate regardless of the resolution. 2Megabits at 
>    > 480x480 is just as much data as 2Megabits at 720x480.
>
>Oh duh.  Of course; I totally wasn't paying attention to the bitrate
>page.  Well, we already knew I was an idiot... :)
>
>				> 			  The difference
>    > is how much data per sampled pixel. Often lowering the resolution and 
>    > turning up the bitrate can increase picture quality but it also depends
>    > on just how clean your source is to start. If you've already got a clean source
>    > then you can get away with a lower bitrate.
>
>Does anyone have suggestions for -their- ideas of reasonable bitrates
>before I spend a bunch of time experimenting?  I have a clean feed,
>and I've been reasonably happy with either "TiVo High" quality, or
>"VHS EP mode" quality (yes, I know the latter is substantially fuzzier,
>and yes, I'm not even talking SVHS :).  Approximate figures for either
>one would make good starting points for my experimentation.  (And if
>anyone thinks that some particular width x height should go along with
>these bitrates, by all means, share.)
>  
>

>Since there's both a bitrate and a max bitrate (4500 and 6000 in my
>current setup, which are the defaults), there are a lot of variables;
>are their any I should stay away from?  Is it sensible to lower the
>bitrate to, say, 3000 or even lower, and does it make sense to leave
>the max bitrate high?  Is this used only during a scene change or
>lots of motion/flow?  I'm using a 350 as my TV-out; has anyone noticed
>any particular bugs/crashes/artifacts from using other bitrates?
>

I've found the info at this site helpful

http://www.mediachance.com/dvdlab/tutorial/bitrate.html

Cheers,

Drew

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