Comments

PeterDuke wrote on 9/3/2014, 7:45 PM
Craftech's expression was "far greater". That seems an overstatement for farss's explanation. Averaging two lines will reduce the noise POWER by one half or 3 dB. One stop is a doubling of the light AMPLITUDE or quadrupling the light POWER (6 dB). So line averaging improves noise by half of a stop. Nice to have but not mind blowing.

Thanks anyway for the explanation.

But when you look at it, you are trading resolution for noise.This can be done on the progressive frame in post, so you have gained nothing really.
NickHope wrote on 9/3/2014, 10:59 PM
The sequence should be for interlaced HD to interlaced SD:

Interesting. I've been doing all mine wrong then:

Deinterlace to twice frame rate (eg 50i to 50p)
Reduce resolution (HD to SD)
Low pass filter
Sharpen and add salt to taste
Re-interlace by discarding unwanted lines (eg 50p to 50i)

Anyone got a really bad HD moire-twitter-inducing clip to run some tests on?
john_dennis wrote on 9/4/2014, 1:30 AM
"[I]Anyone got a really bad HD moire-twitter-inducing clip to run some tests on?[/I]"

While Old Smoke's example video in this thread looked OK in HD, the balusters on the porches can flicker quite rapidly when downscaling to SD.


http://dl.dropboxusercontent.com/u/39278380/HD-DVD/MVI_0002.MP4
craftech wrote on 9/4/2014, 8:22 AM
Peter said:
Craftech's expression was "far greater". That seems an overstatement for farss's explanation. Averaging two lines will reduce the noise POWER by one half or 3 dB. One stop is a doubling of the light AMPLITUDE or quadrupling the light POWER (6 dB). So line averaging improves noise by half of a stop. Nice to have but not mind blowing.

It's more than that. Take Adam Wilt's original review of the Sony PMW-EX1

Sensitivity

When shooting stage productions every bit of extra light gathering ability makes a difference.

John