Originally Posted by zoyd
I'm not sure the Samsung HL-R6768W is an ideal display for measuring horizontal resolution since it only has 960 horizontal pixels on the chip. Does anyone have any data on whether it can actually achieve an effective resolution of 1920 lines/picture width using the "wobulation" technique?
A good point that also occurred to me earlier. One of the few 1080p display (RPTV) reviews I've read mentioning failure to resolve 1920 lines horizontally was a Mits model
tested by CNET. But a few threads, 1-2 years back in the RPTV forum, included screen shots of full 1920 line resolution with a number of wobulation-chip DLP displays. And all the more recent reviews I've seen of wobulation or SmoothPicture (TI's term) 1080p displays have published 1920 line readings. Maybe owners or anyone interested in pinning down the Samsung capabilities can confirm whether it, too, has 1920 resolvability from reviews; (no it doesn't; see my edit below). And of course a DIY confirmation of 1920X1080 resolution for any display is possible with the latest 1080i test DVDs mentioned in this forum, or using the variety of computer software programs generating 1920-line patterns. One reading of 1333 line effective resolution using FIOS should only be a starting point and clearly needs more confirmation with additional measurements.
Btw, the method of multiplying the vertical wedge measurment by 16/9 to get # of vertical lines/picture width only works if you have square pixels. My display does not (16x9 = 1024x768) so when I measure the vertical wedge I get 7.5x100x1.33=1000 which is what I should get.
Interesting point. Multiplying by 1.33 is also the factor used for converting 4X3 NTSC resolution measurements/picture height into resolution lines/picture width. Seems best, then, to use a 1920X1080i/p display for confirming full (test-pattern) resolution, or at least 1366X768 displays for measuring suspected effective test pattern resolutions of typically ~1300-lines for STBs and/or delivery systems. If HDNet's pattern was very crisp out to 1366 lines, then you'd want to try a higher-resolution display to measure STB limitations. (DirecTV's reformatted HDNet resolution to 1280X1080 from 1920X1080 isn't suitable either.)
Presumably, then, the 7.5X100X1.33 reading (overlooking scaling) would mean, with a square-pixel 16X9 display, this HDNet reading, if that's what it was, would be 1335 lines (7.5X100X1.78). If so, that's a typical cable STB reading, especially using a HDMI hookup with a 1080p display (as here
.) Then again, measuring 1335 with a 1024-limited display doesn't make sense!
edit: An additional note about FiosTV, the HDNET stream is 5C encrypted so I can't probe the mpeg stream for format but unencrypted streams like FOODHD and MTVHD delivered at the same bit rate (18 Mbps) is 1920x1080.
Assume most know that the format resolution of 1920X1080, reported on many STBS or cable-STB diagnostic modes, differs entirely from measured effective resolution
. Always useful to confirm a program or delivery source is using the standard 1920X1080, of course. -- John
EDIT: Here's an extract from CNET's review
of the Samsung display used for the FIOS effective resolution measurement:
Resolution is a mixed bag, as the Samsung HL-R6768W didn't actually deliver all 1,920 lines of horizontal resolution. However, unlike many HDTVs, the Samsung does process HD accurately, retaining the resolution in the signal.
So, as mentioned earlier, test disc, software, or pattern-generator confirmation of the actual limitations would be useful, as well as FIOS effective resolution measurements with other displays wtih HDNet's patterns.
The Mits model linked above measured ~25% too low by CNET, or ~1440 lines. But even that would be adequate if a STB and/or delivery system was limiting effective resolution to ~1300 lines.