Quote:
|
how do I correctly train my visual perception to evaluate the different challenges that a video source can present to me
|
I suggest not to actually watch content like watching TV for entertainment, and not listening to audio.
Literally pixel-peeping, while live watching.
Then do use stepping through frames. On a PC VirtualDub is your friend.
Some people will be rather insensitive to encoding artifacts.
(Often with flawed introduction of technical novelties a certain kind of artifact is generated.
The audience adopts the new stuff and demands more: distorted guitars, shaky camerawork, MP3-grizzle...)
What I can suggest is spending countless hours scrutinizing different sources coming from analog mastertapes, then cameratapes like VHS, DV.
Choose test cases. There are lots of reference clips around, ParkRun is one of them.
MPEG-2: Scrutinize dark parts, ripples on water, open fire, crisscross-motion.
The luxury of convincing grain is often unfulfillable here...
AVC: Scrutinize dark parts, expect wet patches in water, leaves.
See how some blurays (Life of Brian) have moving grain along contours,
learn how not to blame this on the encoder, rather on a sophisticated, but a bit overdone regraining.
See other blu-rays exhibit mini DCT-like "tickle noise" instead of smooth grain.
First learn their inborn vulnerabilities, watch their faults.
Then maim your sources while encoding.
Use all encoders DV, MPEG-2, AVC you can lay your hand on.
Watch them degrade the picture as you make them bitrate starving.
Watch dark areas, often macroblocks will be visible there first.
Conclude from the early DCT codecs what the next codec will try to hide these flaws.
Once you easily expect and spot the macroblocking from DCT, mosquito noise etc, you will be able to find their "improved remnants" also in bitrate starved AVC.
In early AVC and HEVC watch the grain move or disappear in wet patches.
Then watch the smearing of bitrate-starved HEVC and you get an idea how our eyes get fooled more and more eloquently as codecs develop. Later hybrid codecs (xvc) can already encode prime pictures from misery bitrates.
Use NLEs if you have them, use their built-in encoders, compare what they do to the source.
(In EditStudio I diff'ed once the decoding result from Mainconcept DV, Sony DV, quartz.dll.
Interesting how the differnet implementations of a simple DCT codec can destroy things differently, only one did well.)
Live Display:
On a PC learn about the different renderers, switch them around.
If it is low resolutions: MPC-HC with/without MadVR.
If its got to be a TV, use a known-not-to-introduce-heavy-processing monitor,
(ouch, which one? I use a rare Loewe 32" TFT where I can turn off any enhancement, no longer in production).
Quote:
|
and , consequently , how to address them correctly with the parameters that a codec like x264 offers me ?
|
Tuning encoders: there is a wealth of information given here in this forum.
Optimal x264 commandlines are here since 2014,
after matching them to blu-ray-quality with restriction of some starve parameter like maxQ, I/P ratio etc
I just give all the bitrate I an afford and indeed add a bit noise to avoid wet patches in dark areas.
And, x265 still sees development, so you just may want to follw the appropriate threads and make test encodes.
And Zopti is as good as it can get IMHO, (I still have to try it)
And, all beauty is in your eyes, I concur with all what has been said here.
Only very rarely I trust tools, as an audio angineer I am happy with 5% weighting for a PSNR figure and 95% for my eyes.