[mythtv-users] Is there a good guide on recording profiles somewhere?

Cory Papenfuss papenfuss at juneau.me.vt.edu
Tue Aug 31 07:10:51 EDT 2004

> I've noticed a lot of people using high bitrates with the PVR-x50's, but I'm 
> using a pretty low bitrate and getting what I consider to be excellent 
> results.  I will admit that I'm coming from about 5 years of having only 
> watched TV after recording everything to VHS in EP mode, so I'm not the best 
> judge of quality (anything beats an EP VHS recording :).  Also, I have a 
> satellite signal piped to the PVR-350 via S-Video (but I'm using nVidia 
> GF4MX440 for output for OpenGL and Xv support), so signal noise/bad signal 
> quality aren't a problem.

 	I've also noticed that a lot of people have seemingly ridiculously high 
bitrates/resolutions.  Of course you can't argue with, "It looks better," but I 
don't trust myself to make such subjective observations.  I've got a resolution 
test pattern thingy I cooked up to try to objectify at least the static 
resolution test... check the thread archives.I still have yet to hear back from 
anyone who's tried it out.  I just bought another PVR-250 (slickwilly's CC $90 
AR retail version)... maybe the rev2 retail won't be as soft as my OEM rev1.

> Anyway, I was wondering what someone with a discriminating eye might think of 
> my settings.  I'm using a bitrate of 2200 and max bitrate of 9800 and it 
> seems to give me the best of both worlds--small files and good quality.  I'm 
> averaging about 1 1/4 GB/hr.

 	I think I use on the order of 640x480, 4000/6000 for what I archive. 
I get about 1.7 GB/hour, and then crunch (with denoising, 2-pass) down to 
352x480 at 2500 for better than SP VHS quality on a DVD.  I've never played around 
large ranges for the encoder, but it might be worth looking at.  I have seen 
ghosting artifacts during high-motion scene changes so it could help.  Anyone 
else comment on large ranges being a good tradeoff for filesize/motion capture?

I've heard that having a large range of 
> bitrates tends to stress the encoder, but I got 50 episodes and 174 hours of 
> Olympics without problems.  Also, I'm using 640x480, but I can't tell a 
> difference in quality between 480x480, 640x480, and 720x480.  I might be 
> switching to 720x480 to make DVD authoring easier, but...

 	Check the archives on my static resolution test.  My experience has 
been the same... indiscernable differences at anything above about 420x480. 
Unfortunately, the PVR-250 *does* lose quality when capturing directly at 
352x480... thus my 2-step process for archiving.  I *really* wish that 480x480 
SVCD resolution was supported as a DVD-standard resolution.... what were they 
thinking?  Maybe like CD-Audio... they didn't want to have a "low-quality" 
"high-quality" because people might not use the "high-quality" one?

> Also, I'm wondering if the poor quality people have mentioned is actually 
> noticeable on the TV or only when transcoding for/playing back on a computer 
> (or other progressive display).

 	"Poor quality" describes a multitude of sins.  I suspect that a lot of 
quality problems people see are bad TVOUT on their vid cards.  My old NVIDIA 
sucked mightily.

> BTW, at the bottom is a nice little query that can summarize your recording 
> profile information in a compact cross-tab format.  I'm posting my data in 
> the standard tabular format because the long-lines of the cross-tab don't go 
> well with  text-based mail readers...  (Oh, and you should probably stretch 
> your terminal window when running the query.)

 	I still have yet to figure out recording profiles.  I managed to make 
another table (localhost.localdomain), and now that's all it uses.  Sooner or 
later I"ll get tired of the condition of the box and redo it from scratch... 
originally built in December '03 on RH9.  Three different motherboards on the 
same install, but it's just never broken to where I needed to do anything with 


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