What compression settings are people using successfully (I have the PVR-250)

[jimbobuk]

I will soon be giving over an entire 80gig hdd to my recordings... I deemed that as most tivo boxes in this country only come with 30-40gig, i'll be happy giving it the extra quality... I have it on DVD Standard at the moment 3.5gig an hour...

I've seen the other post about people having problems with DVD long play... I've not critically tested the settings to see if I can discern the differences... are there performance reasons for going with say "Great quality 2gig per hour" settings...

The thing is I am noticing occasional hiccups.. they vary in how severe they are... I wonder whats causing them... I've only really got SageTV running.. this is my spec

AMD XP2100+
Asus AV7333 MB
512 meg memory
Radeon 9000 (non-pro)
Hauppauge PVR250
Seagate Barracuda IV 80gigs (x3)
Seagate 7200.7 80gig or something.. new drive.. and the one sage uses

All harddrives connected via onboard Raid controller (which makes it impossible to detect DMA as with normal drives but I believe its on by default)

Using the tweaked hauppauge decoder (reg tweaked to be using hardware) ...

I saw a thread the other day where someone said that their machine similar to mine with a 2000XP chip wasn't ideal.. I never really understood why it wasn't ideal... is there anything inherently wrong with using AMD chips of this speed for this type of use..


Mostly recording and viewing my CPU is barely above 10% (straight recording is at like 1-2%... not sure on full screen CPU usage.. hard to see the performance in task manager with Sage full screen...

I wondered what schemes SageTV has in place for managing its buffers... I get nervous watching tv streams and say fast forwarding lots whilst recording for fear of messing up my hdd and causing a glitch in the recording process.. what kind of buffering is in place... I assume the only things that can cause corruptions on the stream as its an all hardware card.. is

i) PCI bandwidth choking
ii) harddrive buffer underrun effectively.. not able to write it quick enough to disk...

option i) i dunno how to fix.. my system has a fair few things in it, but its also CPU wise hardly taxed... or is DVD Standard bitrates rubbing up against the limits of PCI anyways?!?

option ii) if this could be the case.. I know cuda's and seagate drives in general aren't the quickest but i love 'em for their quietness... it is a 7200RPM drive so it must be pretty good.. even so.. playback, AND recording simultaneously with potential fragmentation (only formatted the new drive a few days ago so shouldn't be a problem yet, but the rate files are created with Sage, and the size of them i imagine regular defrags are a must) or different physical positions on the disc by enough that seek time becomes a factor...

Anyways I assume there are methods in place to handle these hdd issues, I just wondered how much memory was allocated over to the buffering of data... I assume as its being written to be stable and efficient the memory allocation is as small as possible... I was wondering if as I have 512meg of memory doing nothing when using Sage... if it would be possible to have options in Sage to use like a 200meg swop file which the card uses for playback and recording purposes... that way hdd issues can be as isolated from the cards playback and recording performance as far as possible.. Is this possible.. would it help... or is it or something like it already being done?!??

Finally just wanted to know what other peoples experiences were like.. I've just watched a show.. a sprinkling of glitches were in it.. mostly minor.. I'll watch some more, and overal i dont think its going to sway me from registering or keeping this card... any measures to improve it would be apprecaited... lowering down to the 2gig codec is obviously going to ease data throughput across the board and hopefully get a much stable playback and recording...

Finally finally... would a hauppauge 250/350 in a new Via mini-itx system be competant enough.. the main reason is the new hush PC is silent.. it has the 1gig chip in.. it really sounds compelling as a by the tv permanently on PVR.... I may get one for other reasons and try in a few months... by then if Sage's network functionality will let me get good performance over 100meg ethernet then that could be my ideal solution... obviously though I'm talking about having problems now albiet minor ones with hardware 2-3 times as fast as that machine.. so I would like to find out how to minimise or mostly remove these issues...

Thanks a lot.. sorry for me asking a lot of questions.. I've really appreciated your help so far.. and overall your software rocks

[Narflex]

To fix your glitches, reformat the partition you're capturing to with 64K blocks instead of the default 4K blocks. This'll reduce fragmentation by about a factor of 16....that means no more glitches.

SageTV runs great in a Mini-ITX box. For awhile I used an EPIAM9000 with a PVR350 as a standalone SageTV box, it ran great. Now I use that Mini-itx box as the client to my SageTV server, runs great that way too.

[ku71]

As Narflex said, you can use 64k clusters to minimize overhead a little, although it won't matter much with so few files.

My recommendation would be to leave at least 2 GB free on the volume. If you fill it to the brim, you force the file system to fragment the files on the search for free space.

My 55 Gb video partition has some fragmentation, the worst being 1.88 GB in 27 fragments. The effect of this fragmentation is negligible - if yours is similar, just ignore it.

Ideally, SageTV would issue a SetFilePointer(1GB)/SetEndOfFile() call when creating a file. This makes the file system aware it is writing a large file, and enables it to allocate the storage in as few chunks as possible.

Martin

[ku71]

I was the one who said it wasn't ideal. Sorry, I did not mean to discourage you ;-)
Some Athlon processors run very hot, which means you need a noisy cooler. This is why I would not buy an new AMD processor to build an HTPC.

[ku71]

turn if system restore for all drives except the drive with the WINDOWS directory

turn of the following services
alerter
messenger
automatic updates
computer browser
print spooler
remote registry
task scheduler
wireless zero configuration (unless you have wireless...)

put the PVR 250 in a slot that does not share interrupts with anything else. the information is usually in the MB manual. for the a7v333 this is the second slot counted from the bottom of the case.

(from earlier post)

Just change these registry settings to 1 while SageTV is asleep or you're not watching video in SageRecorder, or they both are shutdown: 
HKLM\Software\Intervideo\Custom\Hauppauge\VideoDec\Dxva 
HKLM\Software\Intervideo\Custom\Hauppauge\VideoDec\Hwmc

none of this is guranteed to fix the glitches... but it can help

I don't trust promise... try putting the VCR disk on the onboard IDE.

[jimbobuk]

To fix your glitches, reformat the partition you're capturing to with 64K blocks instead of the default 4K blocks.

Ok.. will do this when i can.. at the moment i have stuff on the drive i need to deal with before a reformat... what do i lose in using such large blocks.. do i lose some space.. if so how much!?!? % or amount of a 80gig drive... regardless i think i'll have a go... It may have tried to grow a little larger than i'd of liked tho i dont know if it hit the FULL drive limit.. anyways in only 2 days of use, 1 day of actual recording my drive was 50% fragmented... formatted it today and i'll see how it goes today... I have also turned down my quality to great 2gig per hour... everyone gave me really helpful advice on system setup but no one commented on whether or not using DVD standard was a bad idea for video stream stability... its got to be easier using a lower rate setting... I dont know if ones CBR and another's VBR and whether CBR is better for this... I'll see if i can spot the difference in quality on my monitor or on my projector..

SageTV runs great in a Mini-ITX box. For awhile I used an EPIAM9000 with a PVR350 as a standalone SageTV box, it ran great. Now I use that Mini-itx box as the client to my SageTV server, runs great that way too.

Cool.. what about as the server itself... dunno if this needs much power... the hush pc is really appealing at teh moment.. totally fanless.. a little worried tho as the PVR-250 is so hot its frightening.. the actual board structure is too hot to keep your skin on.. I thought this was a good benchmark as to whether something electrical was too hot (ie. you should be able to stand keeping in contact with it) ... I am worried as this may affect the balance in the fanless hush PC case :/

I was the one who said it wasn't ideal. Sorry, I did not mean to discourage you ;-)
Some Athlon processors run very hot, which means you need a noisy cooler. This is why I would not buy an new AMD processor to build an HTPC.

Ok... yeah i know.. I'm using an SLK-800 with the zalman flower cooler 90mm/120mm fan on bracket cooling.. with the fanmate and the CPU not under heavy load i can keep the fan on minimum spin which all and all makes my system very quiet.. know what you mean though

As for putting card on free IRQ.. will try to do this a little more.. running out of options on that front...

how do i turn off those services!? i'm running win2k... system restore!??? not sure of that one.. I have wireless but its on my router... moving the drive onto onboard is something i could try but unfortunately then the drive you put on there takes priority and becomes the boot drive :/ not easy solution that.. I've often wondered how good the RAID stuff is... used as a normal controller... its the only way i can get as many hdds as i do and 2 CD/DVD drives

[jimbobuk]

did a days of recording yesterday at great 2gig an hour (or is it 2.5) ...

I've only watched an hour show... it did appear to be glitch free which would make sense.. its gotta be harder for PCI and harddrives to cope with higher bitrate recording output.... I could tell the quality wasn't perfect though on my projector... going to try with best today at 3gig... not sure what each profile is... will have to decode the descriptions in the config file later... the best ones etc.. aren't in the default hauppauge app (wintv2000 or something) which would let you look at their settings in a human readable way....

No one really responded as I guess i ranted on about tech issues... I would be interested in people just saying what compression settings they use, have tried.. and if they've had any problems with them... including ... tried all, no problems with any...

I am going to get some screenshots online of the kind of glitches i see... still not sure if the very light snow that occasionally appears could be interference on the tv signal or some card thing.. the main glitches are objects in the wrong place for a frame or two... a person will move to the side briefly etc... typical mpeg glitches.... no visible coding blocks yet...

[Narflex]

I use Great for nearly all of my recordings. I use Best when the rare occassion comes up that I record sports.

[JasonJoel]

I use Best for everything. I don't archive shows though, I am using SageTV purely as a super PVR.

Jason

Originally posted by jimbobuk
did a days of recording yesterday at great 2gig an hour (or is it 2.5) ...

I've only watched an hour show... it did appear to be glitch free which would make sense.. its gotta be harder for PCI and harddrives to cope with higher bitrate recording output.... I could tell the quality wasn't perfect though on my projector... going to try with best today at 3gig... not sure what each profile is... will have to decode the descriptions in the config file later... the best ones etc.. aren't in the default hauppauge app (wintv2000 or something) which would let you look at their settings in a human readable way....

No one really responded as I guess i ranted on about tech issues... I would be interested in people just saying what compression settings they use, have tried.. and if they've had any problems with them... including ... tried all, no problems with any...

I am going to get some screenshots online of the kind of glitches i see... still not sure if the very light snow that occasionally appears could be interference on the tv signal or some card thing.. the main glitches are objects in the wrong place for a frame or two... a person will move to the side briefly etc... typical mpeg glitches.... no visible coding blocks yet...

[jimbobuk]

the dvd ones aren't special in any way as far as creating DVD compliant streams are they!?!?

Ran out of time tonight fighting spam that had built up within 3 days of not checking my mail

Not had chance to watch any Best ones yet.... are the Best, Great etc.. ones CBR and hence more stable/recommended than the DVD ones which are VBR!? I will look at the properties file at some point... Thanks for your codec choices..