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Any advice on --tune grain ? thread
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Originally Posted by benwaggoner
Grain is always the hardest thing for encoders, since it really is random, spatially and temporally. Throwing some --nr-inter in can help smooth out some of the motion of grain, making it both less annoying and saving some bits.
The whole issue of creative intent with grain is quite complex. Battlestar Galactica was presumably mastered with relatively small CRT professional reference monitors. Grain just isn't as apparent on those as on a big LCD panel; CRT itself is a bit of a low-pass filter  . That was the issue with a lot of the first wave of Blu-ray discs; they got approved on $30K professional HD CRT monitors, which didn't show all kinds of imperfections (particularly grain and low-luma blocking) that were glaring on a typical consumer 1080p panel of the era. There was a massive rush in Hollywood authoring studios to get consumer monitors into the rooms so that mastering and QA could be done on a professional AND consumer monitor at the same time.
Same with movies. Things more than 10-15 years old were absolutely approved in projection on a perf screen, which also obscures a lot of fine detail. So the director signed of on something that showed a lot less grain than can be projected by a modern 4K projector on a non-perf screen.
I'm all for preserving creative intent, but spending TONS of bits saving grain that the creatives never approved doesn't seem appropriate. Figuring out how much grain they would have picked is pretty speculative unless the original creatives have done a recent remaster.
Big picture, some well done degrain can actually make the picture MORE like it is meant to be, as well as simplifying encoding a bunch. But knowing how much is "right" is a complex question that will never yield a clear specific answer. |
some good points, well made... i stopped using filters such as nlmeans degrain and nr-inter/nr-intra=x since i finished putting together the custom settings i posted...
with my settings, choosing the right crf value for proper grain removal takes a lot of tests but the file will be optimal, small and degrained. well, maybe keep a hair pinch of noise somewhere... its a constant struggle between noise reduction and keeping detail. if done right, i just consider the lost detail, detail that wasn't there. its like they didn't finish processing the video... kinda like a old blocky video that looks like they forgot to deblock, or maybe it would have took too long... and a re-encode with deblocking makes all the blocks go away, as if the video was meant to look that way and was only half processed.