Vizio p42hdtv10a plasma HDTV: input lag / upscaling /deinterlacing review
This 42" plasma TV dates back to 2005, with 2 component inputs + HDMI, and probably other inputs less useful for retro gamers.
Image quality
Native resolution is 720p. It's bright, sharp, and colorful, though the set I tested had some red/white snow visible on black backgrounds. It exhibits black crush, and relatively high black levels, but I suppose that could be due to the age of my set (manufactured 2006). It does show some color errors on gray gradients (some shades of gray look red, but NOT ALL). You can set 480p to be stretched to wide screen or maintain aspect ratio, but in both cases it cuts off some of the left and right edges of the input, maybe 5-10%.
Input lag (HDMI/480p), measured with a OSSC + 240fps highspeed camera
This TV has a B2W transition of about 5ms. So the input lag varies depending on whether you wait for the TV to reach a steady state (58ms) or measure the first moment that the screen responds to input (54ms).
How I measured: I used an OSSC outputting at 480p. The OSSC lights a LED the moment it starts transmitting the pixels of a white probe over a previously black background. Using a moderately fast high speed camera (Samsung S7, 240fps) you can measure the delay between the LED lighting and the probe appearing on the screen. Since the B2W transition takes some time, the probe gets brighter over 1 or sometimes 2 additional frames.
Side note: the OSSC measures lag in a somewhat unusual way: relative to the moment the probe pixels are sent over HDMI, rather than the start of the frame. So a probe in the middle of the screen or the bottom can actually appear to have less lag than the top. This is because the plasma takes a while to process the incoming image but then once painting begins it actually scans down the screen faster than the data is received, in effect catching up to the signal coming in over HDMI. BUT: since most dynamic sources (ie games) render the whole frame before sending it to the display, it makes more sense to measure relative to the very first pixel rendered (ie the upper corner). For those interested, the center lag is 10ms faster than the top.
Performance: Deinterlacing using OSSC
Without going into too many details... The OSSC uses bob deinterlacing for zero added lag. This looks better when you add light-dark scanlines which masks the inherent "bob" blockiness of doubling each scanline. The result looks good but darker on this TV, with very little flicker.
Built-in TV deinterlacing using OSSC
The OSSC can instead send the interlaced signal to the tv and let it deinterlace. This looks good, better than bob though it tends to some lace artifacts. The cost is lag - an extra 35ms, for a whopping 90ms of total lag. That's huge. Enough you can feel it. But for a RPG the result is nice visuals.
Without the OSSC
The TV comes with 2 component inputs. If you plug directly into them the result is nearly as good as the OSSC. I couldn't measure lag in this setup but I assume it's still about 90ms.
Without the remote
Don't get this TV without a remote. You cannot make any picture adjustments without it; all that remains is switching inputs and "changing volume" (but recall external speakers are required).
Image quality
Native resolution is 720p. It's bright, sharp, and colorful, though the set I tested had some red/white snow visible on black backgrounds. It exhibits black crush, and relatively high black levels, but I suppose that could be due to the age of my set (manufactured 2006). It does show some color errors on gray gradients (some shades of gray look red, but NOT ALL). You can set 480p to be stretched to wide screen or maintain aspect ratio, but in both cases it cuts off some of the left and right edges of the input, maybe 5-10%.
Input lag (HDMI/480p), measured with a OSSC + 240fps highspeed camera
This TV has a B2W transition of about 5ms. So the input lag varies depending on whether you wait for the TV to reach a steady state (58ms) or measure the first moment that the screen responds to input (54ms).
How I measured: I used an OSSC outputting at 480p. The OSSC lights a LED the moment it starts transmitting the pixels of a white probe over a previously black background. Using a moderately fast high speed camera (Samsung S7, 240fps) you can measure the delay between the LED lighting and the probe appearing on the screen. Since the B2W transition takes some time, the probe gets brighter over 1 or sometimes 2 additional frames.
Side note: the OSSC measures lag in a somewhat unusual way: relative to the moment the probe pixels are sent over HDMI, rather than the start of the frame. So a probe in the middle of the screen or the bottom can actually appear to have less lag than the top. This is because the plasma takes a while to process the incoming image but then once painting begins it actually scans down the screen faster than the data is received, in effect catching up to the signal coming in over HDMI. BUT: since most dynamic sources (ie games) render the whole frame before sending it to the display, it makes more sense to measure relative to the very first pixel rendered (ie the upper corner). For those interested, the center lag is 10ms faster than the top.
Performance: Deinterlacing using OSSC
Without going into too many details... The OSSC uses bob deinterlacing for zero added lag. This looks better when you add light-dark scanlines which masks the inherent "bob" blockiness of doubling each scanline. The result looks good but darker on this TV, with very little flicker.
Built-in TV deinterlacing using OSSC
The OSSC can instead send the interlaced signal to the tv and let it deinterlace. This looks good, better than bob though it tends to some lace artifacts. The cost is lag - an extra 35ms, for a whopping 90ms of total lag. That's huge. Enough you can feel it. But for a RPG the result is nice visuals.
Without the OSSC
The TV comes with 2 component inputs. If you plug directly into them the result is nearly as good as the OSSC. I couldn't measure lag in this setup but I assume it's still about 90ms.
Without the remote
Don't get this TV without a remote. You cannot make any picture adjustments without it; all that remains is switching inputs and "changing volume" (but recall external speakers are required).
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