LG 42LC2D TV deinterlacing and input lag review using piLagTesterPRO
This 720p LCD HDTV from 2006 has 2 component inputs, 1 HDMI, and VGA. It's a bit of a hot mess but an interesting test case for the piLagTesterPRO because of how it handles vsync and 60hz sources.
Image quality
Unlike every TV I've tested to date there's no backlight flicker, but you'd never know this by looking at it by eye so that's not really important, just kind of interesting. The display is 720p, but can display 420p/i and 1080i as well. None are pixel perfect however, with significant cropping (20 pixel all around in 720p) and significant aliasing in every mode no matter what the scaling settings. Deinterlacing is done by BOBing, which looks decent but as usual adds flicker.
Input lag measured with a piLagTesterPRO
This display does not have a game mode. I used a piLagTesterPRO to measure input lag. This device sends a frame of video over HDMI and measures how long it takes to display it. Just like the Emprex HD 3220 this TV can only run at 59.94hz. When a 60hz input signal is given the display sends it to an internal buffer which it draws at 59.94hz, dropping an entire frame every 16 seconds or so (see this link for in depth discussion of this lack of proper sync in TVs). Even when given a 59.94hz input it drifts every so slowly (by about 0.1ms per frame), so every now and then there will be a dropped frame.
As such this TV's input lag varies over a range of 16ms. I'm going to report the average here.
If it weren't for the TV's poor sync performance and aliasing issues this might actually be a good set for retro gamers who also wanted something decent for HD content as well. It is has the distinction of having the lowest 480i lag of any TV I've measured to date (this is because it uses BOB deinterlacing, which has the downside of adding flicker). For progressive content the lag is middle of the pack, though it does have an unusually good response time (b2w). By eye I can tell you that it's w2b performance is noticeably worse, however, so there'd definitely be motion blur.
Image quality
Unlike every TV I've tested to date there's no backlight flicker, but you'd never know this by looking at it by eye so that's not really important, just kind of interesting. The display is 720p, but can display 420p/i and 1080i as well. None are pixel perfect however, with significant cropping (20 pixel all around in 720p) and significant aliasing in every mode no matter what the scaling settings. Deinterlacing is done by BOBing, which looks decent but as usual adds flicker.
Input lag measured with a piLagTesterPRO
This display does not have a game mode. I used a piLagTesterPRO to measure input lag. This device sends a frame of video over HDMI and measures how long it takes to display it. Just like the Emprex HD 3220 this TV can only run at 59.94hz. When a 60hz input signal is given the display sends it to an internal buffer which it draws at 59.94hz, dropping an entire frame every 16 seconds or so (see this link for in depth discussion of this lack of proper sync in TVs). Even when given a 59.94hz input it drifts every so slowly (by about 0.1ms per frame), so every now and then there will be a dropped frame.
As such this TV's input lag varies over a range of 16ms. I'm going to report the average here.
I report two kinds of values. The minimum lag is the earliest point any change is detected at the top of the screen. This overly optimistic value doesn't tell you how long it takes to see anything useful, but matches what other reviewers use. I also report a more realistic measure of lag: when the display has reached 80% of full brightness at the bottom of the screen. This combines both input lag and response time, and is closer to what you would actually experience in a game. Since these are the averages, on power on your actual lag will be +/-8ms of the table below.
Full/raw data:
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