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What is the best capture card for picture quality??
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Author:  Ding Chavez [ Sun Apr 08, 2007 7:47 pm ]
Post subject:  What is the best capture card for picture quality??
After having knoppmyth for over a year, I have decided to get another capture card. I currently have a PVR-250MCE and I am quite disappointed with the picture quality of the card, especially when I saw that even the cheapo DVRs that you get from comcast have literally ZERO pixelization. My goal is to get a card that will look great, no matter if it is hardware or software compression.

What card is the best for picture quality in Mythtv?
Please do not post ways to make the picture quality better for the Hauppage cards as I have spent many weekends trying to get it looking good.
Author:  spalVl [ Sun Apr 08, 2007 8:45 pm ]
Post subject: 
I am very happy with my HDhomerun recording QAM over the quality of my PVR-150. Was a little hard to setup with R5E50 though for me.

Problem with QAM though is you may not get all the same channels that you would get with an analog tuner. I'd suggest a DTV card or HDhomerun that can do QAM that way you are setup for HD down the road too.
Author:  tjc [ Sun Apr 08, 2007 10:35 pm ]
Post subject: 
Properly set up with modern drivers the Hauppauge PVR cards are among the best for SDTV.

The most common complaints about SDTV capture quality come from people doing something unwise like recording at the default resolution and displaying at a higher resolution like 1024x768 or 1152x864, especially if it doesn't match the native resolution of their monitor. That kind of multi-generational scaling up and down is almost guarenteed to produce a picture that looks like hash.

I know from personal experience that capturing at 480x480, outputing to the video card at 800x600, and having the card autoscale to TV compatible resolutions (640x480 - 720x480) will make the colors look very washed out and the image to look muddy.
Author:  doog [ Tue Apr 10, 2007 11:14 am ]
Post subject: 
tjc:

So what's the best practice for capture on PVRs then? Should you capture at the native resolution of the monitor? Or maybe capture at 720x480?
Author:  DrGonzo [ Tue Apr 10, 2007 12:41 pm ]
Post subject: 
I capture everything at 720x480 and I would challenge anyone to tell the difference between captured video and live TV at my house. In most cases the captured video is of better quality because my MythTV server is in the basement next to where the cable comes in the house. The run to most of my TVs is across the building so I have a bit of static from signal loss. :P

I also burn some stuff off to DVD so (as I understand it) I cut down on the transcoding by using native DVD resolution as well.

Gonz
Author:  rando [ Tue Apr 10, 2007 1:56 pm ]
Post subject: 
I'm running a pair of PVR 150s as well and am capturing at 720 by 480. I'm handling only SDTV data and like others here would say that you can't tell the difference between a recorded show and a live broadcast.

Perhaps you have either a botched card, or are experiencing scaling issues like mentioned above.
Author:  Ding Chavez [ Wed Apr 11, 2007 6:54 am ]
Post subject: 
I definately don't have any scaling problems. I am capturing at 720x480 and outputing to my SDTV at 800x600. I have always had a problem with ghosting and according to this link http://www.mythtv.org/wiki/index.php/PVR-250 , the problem may be the version of card I have.

The problem is so bad that I cannot have the temporal filter set beyond 5. If I do, the people on screen look very funny. (Their mout will not be moving with their body, like a delayed reaction)

I could try getting another card. Like a PVR-150. They are pretty inexpensive nowadays.
Author:  ceenvee703 [ Wed Apr 11, 2007 7:12 am ]
Post subject: 
Ding Chavez wrote:
I definately don't have any scaling problems. I am capturing at 720x480 and outputing to my SDTV at 800x600.


Except that's the exact situation that tjc mentioned in his message above: capturing at 720x480, scaling to 800x600 (set resolution of the video card), then scaling again back to 720x480 (tv-out scales the computer's resolution back to SD resolution).

Also, it's not a fair comparison to the Comcast DVR if you are subscribing to digital cable: with the Comcast DVR, it's storing the original digital file with no transcoding needed. With the Hauppauge tuners you are either dealing with the (inferior) analog signal, or you're having to re-compress an already-compressed signal.

Having said that, if you're seeing ghosting, and you've already tried the denoise filters, and you're confident that the signal that's getting to the PVR-250 is clean, then maybe you should try out a 150 and see if it helps.
Author:  rando [ Wed Apr 11, 2007 7:50 am ]
Post subject: 
I have my temporal filters set to zero, that's where I see the best picture. I know there are posts around here where people say that when they bumped back up to the default of 8 they saw an increase in picture quality, but for me the ghosting is noticeable at 8 and things look great at 0.

Maybe try that? How do the videos look if you copy them off your box and view them directly on a Windows PC on a monitor without "fullscreening" them?
Author:  Ding Chavez [ Thu Apr 12, 2007 7:08 am ]
Post subject: 
ceenvee703 wrote:
Except that's the exact situation that tjc mentioned in his message above: capturing at 720x480, scaling to 800x600 (set resolution of the video card), then scaling again back to 720x480 (tv-out scales the computer's resolution back to SD resolution).

So should I set my resolution to 640*480?

ceenvee703 wrote:
Also, it's not a fair comparison to the Comcast DVR if you are subscribing to digital cable: with the Comcast DVR, it's storing the original digital file with no transcoding needed. With the Hauppauge tuners you are either dealing with the (inferior) analog signal, or you're having to re-compress an already-compressed signal.

It was a comcast DVR but recording a standard a channel that was not "digital" (channel 7 or something). So the compression would be similar to that of the PVR series.

My overall goal is to have 0 pixelation. But you are all saying the PVR line is the way to go?
Author:  datobin1 [ Thu Apr 12, 2007 8:36 am ]
Post subject: 
640 x 480 would most likely look better try it and see.

Does you tv have any HD inputs? If you use componet, DVI, or HDMI the picture will be much better.

Also some video cards have better tv-out quality do to different chips on the card. (not the GPU but the tv encoder)

What are your capture setting? resolution and bit-rate

If the bit-rate is set to low you will get pixelated picture.
Author:  ceenvee703 [ Thu Apr 12, 2007 10:14 am ]
Post subject: 
Ding Chavez wrote:
So should I set my resolution to 640*480?


It's worth a try but there is scaling involved with virtually any TV-out on a computer video card... even at 640x480. The computer uses square pixels (640x480) but the video out has to send non-square pixels to the TV (720x480) so even there you have scaling, not to mention the scaling if you are adjusting screen size for overscan. And then you have interlacing issues... you have to deinterlace for computer playback, but then it has to be output as interlaced for the TV to recognize the signal.

Basically the only way to get true unadulterated, unscaled, correctly-interlaced playback of the MPEG2 recordings you make are with a MPEG2 hardware decoder like the one on the PVR-350. (The SD video out of a Comcast PVR most likely has this too). You then have correct playback of your MPEG2 recordings, but I believe there are then issues with display of other things, like non-MPEG2 recordings. I don't use a 350 so not sure what the current story is with it.

One good way of testing your recordings is to make a DVD of them, then play it back on a set-top DVD player hooked to your TV. If the recordings look great, all the quality issues are due to your video output, and you would get similarly-great-looking results with a PVR-350's MPEG2 hardware decoder output.
Author:  rando [ Thu Apr 12, 2007 10:23 am ]
Post subject: 
Quote:
One good way of testing your recordings is to make a DVD of them, then play it back on a set-top DVD player hooked to your TV. If the recordings look great, all the quality issues are due to your video output, and you would get similarly-great-looking results with a PVR-350's MPEG2 hardware decoder output.



Another option is to copy the file to another PC and play it back on a PC monitor without resizing it to full screen, again if this looks crisp and good (though it'll be a smallish window likely) then your input source is good.
Author:  tjc [ Thu Apr 12, 2007 7:39 pm ]
Post subject: 
The vertical scaling (or possibly scaling in 2d) seems to make a bigger difference in output quality. capturing at 480x480, 640x480, or 720x480 all look pretty good played back at 640x480 but crappy at 800x600. With the latest generation of ivtv drivers many PVR-150's have tearing glitches at anything but the "native" resolutions for NTSC and PAL, so I tend to use 720x480.

X modelines matter too. The ones I use (and have posted many times) give me a sharper picture with the S-Video output to my old Panasonic TV. Some of this is just trial and error. The Pansonic is pretty picky about what modelines it will tolerate but for the ones it does like the results are generally good.
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