Well I'm am just about to give up and buy a new TiVo box. The system basically works, and I am sure I can get the final pieces in place (IR controls, guide, etc.) but the quality of the video is just not as good as my old TiVo. Granted I have degraded my system by going back to cable from DirecTV, but mythtv video quality is just not up to the quality I would get from a TiVo box.

I don't believe its a tuner configuration (like tuner type) issue since the quality is 90% of the way there. Its almost as if the hardware is not equal to the TiVo stuff. I am running:
> Abit NF7-S2G MB with a Sempron 2400+
> 512 MB RAM
> PVR-250
> Samsung 160 GB drive
> GeForce MX4000 64MB AGP 8x card (sVideo to 32" TV)
> pci cards for sound, lan, IDE (to get DMA working, hdparm -tT now shows about 400 for cached and 50 for non cached)

In addition to the video being grainier than TiVo, playing LiveTV the video is not as smooth causing the sound to seem a touch out of sync. The grainy picture is a recording issue since I see it when I play back recorded programs on my Mac using MythFrontend. Using my Mac to play back recorded video, or watch liveTV gives smooth video and audio sync, but the grainy quality is a notch below what it should be.

Can I get improved quality? If yes how? I've dumped more money into this than I planned, but I am willing to throw more money at it IF its not throwing good money after bad. I know this is herasy, but would I get better quality using the Windows based BeyondTV? I don't want to go that route because I want to use my Mac as a front end in my bedroom.

Have you tried turning off Transcoding by default? (in recording profiles)

Adjust the bitrates for MPEG2 recording. 8000 normal 16000 max should give you as good a video quality as you can get.

Try bumping resolution to 720x480 (this is usually not helpful as most TVs barely display 480x480 in NTSC)

Thanks!

Andrew Lynch

Now that the R5A9 release is out maybe you should consider it for better hardware support of you motherboard. As I understand it, R5A9 uses kernel 2.6.10 which probably supports your mb better than R4V5 does.

Thanks!

Andrew Lynch

The issue here is twofold:

* quality of the recorded file
* quality of playback through your video card's TV-out

The PVR-250 is basically in charge of the first issue. There have been some questions raised about the quality of recordings with more recent versions of the ivtv drivers, so that might actually be a factor that (if not corrected) could be a quality difference between the ivtv drivers used by MythTV, and the Hauppauge drivers used by BeyondTV.

I'm using R4V5 for my backend, though, and my 250's recordings are absolutely fine when I burn a DVD with the recordings and play it back on a set-top box.

Which brings up Issue #2:

Virtually all TV outs on PC video cards do not properly play back interlaced recordings. The files are interlaced; the TV-out signal has to be interlaced; however, there is no apparent way to "pass through" interlaced playback so that video motion (like a CNN ticker or a football game) is smooth. This is true under both Windows and Linux, from what I can tell.

Dedicated MPEG2 decoders, like the one found on the PVR-350 and the MediaMVP, _do_ properly synchronize playback of MPEG2 recordings to the video outs, and motion looks correct. And so does the TiVo, of course, as well as DVD player set-top boxes.

Basically, I've come to an acceptance that it will not look "right" until much more complex deinterlacing schemes are available for playback from within MythTV.

Does that mean I should downgrade the driver?


Does that mean you suggest puting in a PVR-350 card or MediaMVP? If yes what implecations does that have for the exisitng PVR-250. Will I have problems?


I was wondering about that (what kernel R5A9 uses) but I was afraid to ask

I can't tell from your post what version of KnoppMyth you are running. If you're running R4V5, like I said, the ivtv version looks fine to me. I'm not sure if you can downgrade if you're running the R5 alpha; I seem to think you can't.



MediaMVP is an external box: I just mentioned it as evidence that correct playback and output of interlaced recordings is possible.

Should you get a PVR-350? I'd probably say to look at the forum here and the wiki and see if you think it's worth the extra money and extra installation work to get it up and running. Some people like the look of the output (probably those who can tell it's getting the interlacing correct) and some don't like the image quality as far as colors and brightness goes.

actually current R5alpha is using a highly patched 2.6.9 kernel.

the pvr350 supposedly has great tv output quality. Don't know never used one, however it is MUCH more difficult to setup, and it will not playback anything other than mpeg2 smoothly.

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

I am running on R4V5 and prefer as close to out of the box as possible. thus PVR-350 is OUT (at least for me). Maybe I'll try the R5Alpha since maybe my problem is all the stuff (disk, video, etc.) going across the PCI bus

have you actually plugged the cable directly up to the tv to make sure it's not just the difference between the sat feed your used to and the cable? I know here the first 99 channels on cable are analog, and can be pretty bad quality. I know my ota recording from my hdtv card (even when recording sdtv via digital signal) is far superior to what I get either through mythtv or directly on my tv set.

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

Yes, and there is definately a grainyness difference. I'll play around with the settings to see what I can get.

By the way, I have been looking for R5A9 and all I can find is from bittorrent (no actual download sites). Is that right? I'm using torrent, but it will take hours

Generally don't believe the time estimates for torrent untill much later in the download, so this may be too late for you.

However while I don't see it advertized anywhere, some of the download sources for R4V5 are also carrying iso's for R5A9. Go to http://www.mysettopbox.tv/knoppmyth.html and drop through some of the sources.

Good luck.

-Rusty

_________________
Master:
- AMD 1800XP on a MSI KT4V motherboard, via KT400 bios
- 120 G Segate Baracuda /, /cache, /myth, swap
- 200 G Segate Baracuda /myth/tv
- 3 Haupauge! WinTV PVR250s
- 19" Daewoo Monitor (1280x1024 ni)

I agree here and with xsecrets. my 250 records video as good as my calble box can produce. DVDs burned from my 250's output are perfect. live playback of the video on my VGA monitor, also perfect....scrolling ticker and all!

_________________
R5F1 - Dell P4 2.4Ghz 500MB - PVR250 x 2 - GeForce FX 5200 - Onboard sound/NIC 80GB ATA/250GB ATA/400GB SATA

I had the same problem till i did a clean install or moved the card to a different slot .i use the middle one. Major difference.. it thought it was that i didn't have it seated properly till i read some posts on the forum that talked about moving the card around.

Well, if you are going to do a clean install, wipe the system and restart with R5A9 and see if you can eliminate some of the old funky cards you had to add to your system to work around the non-support of your mb. Having a rack full of old PCI cards can't be good for EMI.

Is KnoppMyth HTPC as good as a Tivo... ?

No, I think KnoppMyth is fundamentally a better deal. Maybe there are some improvements here and there to tweak it a bit but the foundation KnoppMyth is built on is superior to Tivo.

If the suits MPAA/RIAA whoever decide they don't like Tivo for whatever reason, they are one lawsuit away from putting that company out of business forever and then the Tivo boxes are most likely scrap due to nonavailability of drivers. Not true with KnoppMyth. Its worth the investment.

Thanks!

Andrew Lynch

Actually I was talking about the hardware part of TiVo, not the software part which KnoppMyth is way better.

I played around with the system last night (as I it took hours for R5A9 to download from a mirror site), and discovered the following:
1) On bright pictures or bright colors, the quality is fanatstic.
2) On dark pictures or dark colors the quality is grainy.
3) On slow moving pictures the quality is better than fast moving pictures, which I would expect based on the way MPEG compression works. What I would NOT expect is that fast moving pictures have jerky playback on my KnoppMyth box (but not on my Mac). Maybe its always jerky and I just don't notice it on scenes with slow movement, but I don't think so
4) Some channels are better than others. This is definately a cable quality issue, although the TV tunner seems to handle it more gracefully than Myth. I suspect I will need to edit the channels and play around with the tunning numbers. Is there a way to get to that screen without redoing mythtv-setup?..... That reminds me last night when I ran mythtv-setup I got a message about a GLX (or something its hard to read on the TV screen) lib not being found in the X11 config file. It then continued OK.

Based on the other suggestions I will try with R5A9 (hopefully removing some PCI cards) and with moving the card around.