I just purchased the SV420M from Wally for $800 after tax, quite a nice bargain. Ive been out of the HTPC scene for a bit, but I have also been waiting for LCD display technology to reach an acceptable level of performance yet be close to my price point. I had been using a Sony 1080i CRT for about the last 5 years because of LCDs lack of contrast.
Well that time has come and I believe I made the right decision.
The refresh rate/contrast ratio/viewing angles on this LCD compared to LCD's 4+ years ago is amazing. I would assume the specs are reasonable to the public since CRT manufacturing is pretty much done and LCD's/RP/FP/Plasma are now exclusive. Also, there is no backlight bleed whatsoever.
My rig is a little bit old:
P4 2.8 GHZ
ATI Radeon 9800 AIW Pro
*Video connected DVI > HDMI cable on HDMI3 plug. Audio connected 1/8" > L+R RCA.
The rig still does the job until I can snag an i5/LGA1156 microatx with its on CPU die graphics chip (sufficient for email@example.com).
Here are the basics of what I have discovered so far and this maybe useful to some readers. I have watched a ton of movie clips, in various formats at various refresh rates; repeating the same scenes over and over until I practically memorized the script. All while looking for judder and testing different interpolation settings.
NTSC movies (USA) are encoded in 23.976fps. PAL movies (European) are encoded in 25.000fps. NTSC movies would be 24fps exactly if they hadn't introduced color into the frequency sometime in the 50's or so. Simple enough.
This TV of course is advertised as 120Hz and sold in the states. Generally other TV's are 100Hz that are sold in Europe.
For NTSC broadcast, lets round that 23.976 up just to simplify things. 23.976fps = 24fps. This 24fps of course divides evenly (by 5) into the 120Hz the VS420m refreshes at. This means that there are 4 frames for every 1 that need to be reproduced when the panel refreshes every second.
For PAL broadcast, 25.000fps divided evenly into the 100Hz TV's marketed in Europe. So for every 1 frame, 3 are created.
When the VS420m creates these frames to match, it can either duplicate the 1 frame 4 times or can interpolate (or deduct what should come) next the 4 frames. If smooth motion is on, it interpolates and if it is off it just repeats.
Smooth motion has two different algorithms: smooth and precision. Smooth mode is a more 'accurate' interpolation since it fills 4 frames to 1. Precision mode however first up converts the 24Hz to 60Hz using 3:2pulldown (which should introduce judder and is exactly what happens on traditional LCDs) and then uses 2:2 pulldown to create/interpolate 1 frame for every real frame.
So I installed two amazing programs: Recode (to synchronize the video coming from the media player) and Powerstrip (to synchronize the refresh rate from the computer to the VS420m) and tried both NTSC and PAL content.
With NTSC content I set Recode to 23.976hz and Powerstrip to 23.976hz. Flawless picture. Since the video was originally filmed and encoded this way, it matches the refresh rate of the player with Recode and the computer with Powerstrip. I used low and medium smooth settings, and used Smooth mode interpolation.
With NTSC content and Recode and Powerstrip both set to 24.000hz, the video just appears ever so slightly different; perhaps a little less smooth, very hard to say.
With PAL content, I can see what looks like a hickup. The video of course is originally 25.000hz, which doesnt match my Recode/Powerstrip settings. I would expect this hickup using a fps/refresh rate made for NTSC content.So how to be compatible with all content and still make use of the advertised 120hz refresh rate?
Well you're going to have to sacrifice smoothing. I personally like smoothing but sadly it's more of a marketing ploy than anything since smoothing is more easily seen by customers than 120hz refresh rate without judder (which these panels natively do without smoothing enabled if the source refresh rate matches a divisor of 120hz since they always refresh at 120hz)
When the computer resolution is set to 1920x1080p@60Hz, all smoothing and "advanced settings" are completely disabled. This is because the VS420m is receiving the 60hz signal and detecting it as an already calibrated PC input via HDMI. One thing you may notice is that your brightness is significantly higher. This is because the graphics card is now the brightness control for your 60Hz PC signal.
With this 60hz refresh rate being delivered from the PC to the panel, the panel is natively performing 2:2 pulldown (matching every real frame with a duplicate to make 120fps). Natively of course there is no judder like this from the PC to the panel. If we look a bit more in depth though, when playing video both PAL and NTSC content are being processed using a 3:2 pulldown to match the computers refresh rate at 60hz, then 2:2 to match the panels refresh rate at 120hz. Nearly the same exact thing the precision setting does minus the smoothing effects from interpolation!
If you want to get the best from NTSC content like Bluray etc you will have to do two things:
1. Use Recode to match the media player to the computers refresh rate at 23.976hz.
2. Use the advanced graphics settings, or if you must use Powerstrip to match the computers refresh rate to a traditional 23.976hz recognized by the TV.
3. As a personal recommendation use either low or medium smooth settings and in Smooth Mode as not to introduce any 3:2 pulldown.
If you want to use both PAL and NTSC or plan on using the VS420m as a monitor for browsing and such, run the native resolution at 1920x1080p@60hz.Home Theater Mag Review