Stuttery video in DVB-t (UK) (1 Viewer)

[eNRGy]

Hi all.

I have Mediaportal (With an SVN from last weekend) and TVServer3 (Same) running really well on my HTPC setup.

I'm generally really happy with it. The TVServer in particular is a great step forward and Mediaportal is a fantastic application.

However I have one little problem. When watching TV, the picture seems good to my eye, but any scrolling text (Such as news tickers or program credits) are almost unreadably "stuttery". I don't know how else to describe it. It's like a really low frame-rate and blurred.

I have a Black Gold dual PCI-e card and a Nebula PCI (Both DVB-t). The machine is a Intel Core2 6300 @ 1.86ghz and 2gb of RAM. The Windows XP-sp2 install is fresh. I'm in the UK on the Emley Moor transmitter.

This is connected to a LCD HDTV 37" via a PC: VGA -> TV: DVI lead ( DVI -> DVI doesn't work with my tv for some reason.. that's an issue for another time and place) in 720p (1280x720@60hz)

Comparison of the same channel on Sky or an ordinary Freeview box via SCART is much better looking and more readable (it's smooth), while the PC output looks almost unreadable.

I'm a video "n00b", so this is a complete mystery to me. I had no joy searching the forums and google for similar problems, probably because I'm using the wrong language.

Any ideas?

 

[petzlux]

i would check the de interlacing settings, which are probably wrong. as you use the vga out, you are outputting a progressive signal. so the pc needs to deinterlace the signal (afaik dvb-t is interlaced ? )

 

[Paranoid Delusion]

What Graphics card are you using, needs to be DX9 compatible with 128mb memory (recommended).

This is the one thing specification wise (important) you did not say.

 

[TritonT]

Bit short of info to help you properly (would need - are you seeing the same problem with TV Engine 0.2, make a model of your graphics card, make and model of your TV), but here goes.

You are definitely sending the TV the wrong refresh rate, should be 50hz not 60hz in the UK.

You are probably sending the TV the wrong resolution. You normally get the best picture by sending the exact resolution that your LCD panel has. At a guess this might be 1366x768. If you are being forced to use VGA instead of DVI make sure the cable is the best you can find.

ATI and nVidia graphics cards behave differently when sending 1280x720x50 or 1366x768x50, have a look on AV Forums. Driver version is important (some people say that the last Forceware driver to work properly at 50hz was 84.21!!!).

Codec makes a big difference, I'm currently using nVidia PureVideo with De-Interlace Control set to Automatic.

Make sure that in MediaPortal Setup under Television, Deinterlace mode should be set to none.

Also, sometimes it just doesn't work out, for example I have a DLP that does not play well with ANY nVidia card.

 

[petzlux]

Try different resolutions, but most LCD tv's wont do 1:1 pixelmapping, in other words, display a signal in their native panel resolution natively without introducing scaling artifacts (my toshiba 32c3030 doesnt do 1:1 pixelmapping at 1366x768).

But for a HTPC, this I believe is not important, as most video material anyway will not be in that exact resolution. I left my HTPC output at 720p, eg if I watch a 720p video, it will be scaled only once, by the tv to 1366x768! And I believe that the TV's internal scaling algorithm is better optimised to its panel than a generic PC scaling algorithm.

[Sorry went a bit off topic here, hope someone finds this useful]

I cant help you anymore with dvb-t, as my dvb-t card was dead on arrival, and AriaPC from which I ordered still havent processed the Return after one month waiting !!! Arghhh need to call them again, but their useless at their call center, always say that they will call back, never do!
[sorry went off topic again, but needed to get this off my chest!]

 

[f0rmula]

Whenever I've viewed DVB-T or analogue signals via a PC, even on a monitor, credits at the end of the program have been pretty much unreadable. Same goes for any moving text. I've always used Hauppauge cards, but have observed other brands of cards doing similar. I also saw it happening under MythTV. De-interlacing helped a little, but not a huge amount.

I don't know quite what our problem is, but I don't think it's anything to do with how you're outputting to the TV. I'm pretty sure I have exactly the same issue on a monitor.

I'd recommend playing with whatever interlacing settings you can.

James

 

[gloomyandy]

The problem you are describing sounds like the classic issues when using the wrong refresh rate. If you are in the uk (or Europe) you definitely want 50Hz not 60Hz. For me I found that having 50Hz made a huge difference to how things like news tickers looked.

Andy

 

[allanp81]

I have my LCD screen set at 50hz and this problem still exists.

 

[baffledboy]

allanp81, It's all very well having your LCD screen set at 50hz, but you MUST change your graphic card properties to output 50hz or a multiple thereof.

 

[allanp81]

Erm, well I have?!?