VGA vs HDMI vs Refresh Rates (1 Viewer)

[5Hundred]

Sealen, let go of the 60hz thing, LCD TV's dont always run at that frequency!

When you state that they "do some magic to get it to look right" i would suggest that you're not really up to speed on this stuff. Theres lots of nonsense posted elsewhere regarding source material and display refresh rates please don't add to it.

 

[SEALen]

Yeah, yeah, most LCD use 60Hz.. there are a few new ones are starting to use higher. My 1,5 Year old LCD uses 60Hz. And I feed it with 50Hz Pal TV via scart RGB. So the electronics in the TV do some "magic" with that to display that 50Hz Interlaced signal at 60Hz progressive. I can't be bothered learning all the math involved in that transformation so I'll just call it magic okej?
When I run my HTPC I output 1360x768@60Hz via VGA. So then my computer/gfx card do all the "magic" with transforming the different sources into 60Hz.
Anyway, I'll stop generalizing from now on.

 

[kenwonders]

Yeah, yeah, most LCD use 60Hz.. there are a few new ones are starting to use higher. My 1,5 Year old LCD uses 60Hz. And I feed it with 50Hz Pal TV via scart RGB. So the electronics in the TV do some "magic" with that to display that 50Hz Interlaced signal at 60Hz progressive. I can't be bothered learning all the math involved in that transformation so I'll just call it magic okej?
When I run my HTPC I output 1360x768@60Hz via VGA. So then my computer/gfx card do all the "magic" with transforming the different sources into 60Hz.
Anyway, I'll stop generalizing from now on.

No, you are wrong. If you send 50hz to a TV that supports PAL over HDMI (every LCD in EU pretty much) then you will most definitely be running in 50hz. There is no magic involved, just the correct rate. Please stop spouting this magic nonsense.

It is simple to demonstrate using any channel with a ticker. You can't fake 50 into 60 and get away with it on such channels. I personally use non-native resolution HDMI over native resolution VGA for this exact reason, and the effect is obvious.

 

[SEALen]

Okej, ppl here is a nice little guide to the "Magic" I'm refering to. The match is just to bothersome to learn so I'll go on calling it "Magic". Please read it before you comment again.

Video Frame Rate vs Screen Refresh Rate - What You Need To Know About Video Frame Rate and Screen Refresh Rate

My TV uses a 60 Hz refresh rate. It does not change ever.

 

[Slurm]

The magic you are referring to is called pulldown and has been shortly discussed in this thread. It only occurs when fps and RR are not the same.

Since most modern LCDs are able to display all the needed RR (24, 25, 30, 50, 60 Hz) there's no need for pulldown anymore except if you do a multiple of the Framerate (ie. show 24Hz content with 48 or 96 or even 120Hz - this is called 2:2, 4:4 or 5:5 pulldown).

The available RR on the LCD depends on the type of connection as also previously said. As far as I know on D-sub you can only have 60Hz (and sometimes a bit more) but not 24 or 50. But using HDMI gives you all the RRs you need.

 

[doornjoostje]

With your nvidia card, it is possible to add a custom resolution with a custom refresh rate. Be sure that the interlaced gets deselected and select a 1366x768 with 50 Hz. Good luck, works briljant here.

 

[kenwonders]

Okej, ppl here is a nice little guide to the "Magic" I'm refering to. The match is just to bothersome to learn so I'll go on calling it "Magic". Please read it before you comment again.

Video Frame Rate vs Screen Refresh Rate - What You Need To Know About Video Frame Rate and Screen Refresh Rate

My TV uses a 60 Hz refresh rate. It does not change ever.

As I said before, if your TV is in EU it mostly like accepts and displays 50hz perfectly without any frame multiplication. What is make/model? A Mediaportal box outputting TV using a bob or DXVA deinterlacer will make 50 frames a second. If you connect via a 60hz VGA or HDMI connection then the HTPC will double 10 of the 50 frames to make up 60. This will result in only a slightly noticable stutter during normal TV, but very obvious for credits or tickers.

If you have a PAL compatible TV, pretty much every TV in EU, then you can connect via HDMI/Component (not usually VGA) at 50hz and get 1:1 refresh rate timing. See this tool: https://forum.team-mediaportal.com/mediaportal-1-talk-45/automatic-refreshrate-changer-44338/ for how to achieve the correct rate for all your media types.

This does not apply so much with 24hz. For example, although my UK LCD TV can do 50 and 60hz perfectly, it always takes 24 or 48hz connections as 60hz interlaced, and hence I get pulldown applied regardless of whether I use 24hz or 60. Many new TVs can, either via directly running at 48hz or 96 or other multiples that still maintain correct frame timing.

I'm not sure what you think is in that document that contradicts what we've been saying?

 

[Slurm]

I think SEALen is talking about his special situation where he connects his PC via D-Sub (VGA) to his LCD. Here (for most LCDs) it's only possible to use 60Hz.

And I think he's preferring D-Sub over HDMI (which his LCD supports also with 50Hz) because of the better picture quality with nearly 1:1 pixelmapping.

Using HDMI on 1366x768 displays gives great overscan (which can be compensated by display driver) and scaling because HDMI uses 1280x720 (or 1920x1080).

 

[5Hundred]

Sealen, you've obviously bought the worst LCD TV known to man then as it can only do one refresh rate (Your manual shows that it can do quite a few even with the PC input e.g. 60, 72 and 75 HZ)

Remember that originally you stated that all LCD's run at 60HZ only, what we're saying is that is incorrect. Just because your choosing via you're connection type to run at 60HZ always and then let the graphics card do some "magic" does not mean that this is necessarliy the only or correct way to deal with different refresh rates in your source material.

For the rest of us (as the article you posted actually confirms!) our TV's can do different refresh rates, thereby negating the need to do any 3:2 pulldown. It's quite noticeable on mine if i display a 24fps movie at 50HZ i get slight juddering. However if i change the refresh rate of the TV to 24fps the movie smooths out nicely. You may not have noticed but there is a whole plugin (automatic refresh rate changer) devoted to this.

Sealen i honestly think you're missing the point, there's another element to this that has escaped you. Yes a 60 HZ LCD can display a 50HZ signal by using "magic" but also it can change to being a 50HZ LCD which is far better and smoother for displaying a 50HZ source.

 

[Slurm]

Sealen, you've obviously bought the worst LCD TV known to man then as it can only do one refresh rate (Your manual shows that it can do quite a few even with the PC input e.g. 60, 72 and 75 HZ)

My previous LCD (Toshiba 32WL56) had the same problem: I was only able to get 60Hz or 85Hz via D-Sub (75Hz gave me a totally shifted picture which even Powerstrip couldn't correct). HDMI and YUV was also possible and here I was able to switch to 50Hz but the picture was blurry and no fun to view. I finally sold it and bought me a new one that's able to view all needed RRs.

And here I found a list of VGA Signal Timings http://www.tinyvga.com/vga-timing: As you can see for 1368x768 (the recommended resolution for 1366x768 displays) there's only 60Hz possible (of course a LCD could do more but that's not standard).

With your nvidia card, it is possible to add a custom resolution with a custom refresh rate. Be sure that the interlaced gets deselected and select a 1366x768 with 50 Hz. Good luck, works briljant here.

SEALen uses D-sub where 1366x768 (at least with nvidia) is not possible. He's limited to 1360x768 or 1368x768 (the value has to be a multiple of 8). And his LCD doesn't support 50Hz over D-sub.