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Old 14th February 2023, 22:36   #78  |  Link
DTL
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Join Date: Jul 2018
Posts: 1,036
"keep watching SD BT601 8bit 100 nits stuff on their TV 'cause "it just works"..."

Only extra poor people watch SDR content at 100nits very poor displays (I also use such Philips-china 4K SDR model). Though poor people are most at this planet nowdays. Other can watch colour SDR movies at the daylight at sunlight-viewable displays with 2000..4000+ nits of max(nominal) white. Way better in compare with HDR-capable displays for poor people rated for limited time and limited part of frame peaked brightness to 1000..1500 nits. SDR really not limited to displaying setup of only 100nits and also viewing colour content at so low brightness you limit best colour viewable range to about 10:1 . Below 10nits human vision start to degrades colour saturation and below about 0.1..0.01 it decays to greys only. So to view about 1000:1 dynamic range of 8bit SDR in full colour having dark grey (about 17..18 code value at 8bit limited) at 10nits it is better to have DolbyVision-class 10000 nits fulltime fullframe unlimited display (not very cheap product and eating lots of power). And viewing conditions about mid-shaded daylight about 1000..5000+lux average room lighting (also only very poor people have very dim lighting about 1xx lux or lower at evening/night resting at home after all day hard work).
10000nits are really not any great brigthness - the about 0.7 diffuse reflective office paper at direct sunlight 100000lux have brightness about 20000nits and you still not have any headroom for highlights (natural sun highlights can go significantly higher 100000 nits - like in water objects and so on still non-metal mirrors).
So even still not present at poor people market possible HDR-10000 displays still not cover standard daylight diffuse only reflecting scenes with 'natural 1:1 physical brightness mapping'.

"but can you imagine how long H.264 will stick around? I mean, it was such a good codec in terms of patents and x264 was such a good encoder that it will probably stick around for years to come and the fact that broadcast companies adopted XAVC Intra Class 300 and 480 for UHD workflows will make it stick around even longer ehehehe."

In distribution and endusers it mostly probably till the end of current civilization (possibly less 1 century time left, or even much less). h.264 and x264 for AVC-Intra encoding is possibly very poor solution when you try to cosplay some better MJPEG coder with completely different target designed MPEG coder.
As you see todays it end with very poor performance when about somehow optimized by residuals of programmers frame analysis part in x264 run at about 10% of processing time. And may be 80 and more % of time for your I-frames coder cosplay from x264 you run with very non-optimized CAVLC not-video non-image oriented simple raw data compression engine. And more badly it is forced to keep about equal output bitrate with significantly different in complexity frames without permission to simply keep same quality level and fill bitstream with zero stuffing when frame is simple if your application forces you to have constant bitrate.

So it looks in AVC-intra I-frames CBR encoder cosplay the x264 program runs tons of iterative loops of different quantizer blocks encoding and after (slow and not optimized) CAVLC compression tried to see if it reach your target system bitrate any good. Not really nice solution. CAVLC data compressor is unlikely will be optimized because it is already replaced by better CABAC at general poor public usage and your old industry standards for AVC-Intra not allow to use CABAC - bad.
May be for professional industry exists some hardware ASICs for this AVC-Intra CBR encoding. General public unlikely need such slow and not optimal solution with varied quality over frames and slow encoding rate algorithmic solution. So general usage of x264 is crf-based IPB VBR.

" there's one thing I'm particularly happy about: more stops in cameras and more nits in contents."

1. About several decades already may be from begining of rec.601 digital the good quality broadcast-class video cameras had HDR internal processing - it required to have about 600% non-clipped dynamic range above nominal white (for 2/3 chips classic SD camera). Better product may have 1000% and more range above nominal white. At the 'before public HDR standards' time the camera control person may either hit AUTO KNEE option or manually play with KNEE POINT/ KNEE SLOPE adjustments per scene to have _non_standardized_ HDR compression of scene highlights into SDR valid codevalues range (8 or 10bits). So some 'non-standard-HDR' are really work non-advertized over many decades. With good broadcasters using not very cheap low dynamic range cameras. Only because of per-scene manual or auto-compression of dynamic range without signalling about it - the decoder display device can not fully decompress its range close to natural-scene linear. But it displays without hard clipping. The public-HLG HDR is only putting normatives to compression transfer curve of highlights above nominal (diffuse) scene white. So display device can perform better backward decompression of range above nominal white (and display more or less correctly depending on how much power of light do it have).
Also as cameras start move from SD to HD the noise-limited dynamic range become lower so we were need some years of advancing of incamera noise reduction so you again have about 60dB SNR at HD (and may be already in UHD) camera with still providing some headroom untill white clipping to have data for HDR compression.

2. Nits is completely not directly connected to the displaying of SDR or HDR video system. As described above. Nits only depends on how many money can put customer in display device to have none or time/area-limited or unlimited high-nits display. The xvid-coded 8bit SD/HD SDR content may be nicely displayed at good 2000+ nits full-time full-frame unlimited daylight vieweable open air home private person usage display device.
(image from https://www.tomsguide.com/reference/...est-outdoor-tv , may not displayed in forum)
To not live in dim grey visible environment poorly and partly visually coloured and to see full saturated coloured range down to the very darks we need to live in good enough lit areas (or good enough lit indoors).
Sorry for users of HDR-like hardware of area+time limited poor 1000nits cheap displays for poor general public. No usage of AVC or 265,266 or more numbered by geeks codecs can help to display real physical power light and visible colour range if not enough money put to power of hardware light. So WCG+HDR with very dim 1000nits or less poor displays also really not fully correct stuff. The dangerous words 'colour volume' already passed to public market and only good enough powered displays can reach really good visible colour volume (not just encoded in zero-cost digital file of any codecs/bitdepth).

Last edited by DTL; 14th February 2023 at 23:06.
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