[Cin] Is the Waveform properly calibrated ?

Andrew Randrianasulu randrianasulu at gmail.com
Fri Nov 20 02:52:03 CET 2020

В сообщении от Friday 20 November 2020 04:31:08 Pierre autourduglobe via Cin написал(а):
> I don't know how to check these filters, they don't match the 
> Cinelerra-GG plugin names.
> Pierre

also found this article, it says software monitors not always right ...


Video Levels - Digital
Digital video formats that follow ITU-R Rec. 601 (DV, DVD, etc.) store video in Y'CbCr form. 
In simple terms, the Y' component (luma) stores the "black and white" information 
(Cb and Cr are the color difference components). The Y' component determines 
black level and white level. For 8-bit formats like DV and DVD, the Y' component 
can range from the values 0 - 255. Video is primarily stored in the range of values 
from 16 -235. The remaining values are for video over/undershoot. (And the value 0 
may be reserved for synchronization purposes.) Please note that the analog unit IRE 
does NOT apply to the digital domain.
Proper black level is at 16 (Y').
Proper white level is at 235 (Y').
This is true for the DV and DVD formats, both PAL and NTSC.

Please note that application-based waveform monitors (i.e. in your NLE) 
are unable to measure analog levels! They cannot tell if your digital-analog 
converter will convert levels properly or not. Don't get confused by any settings 
that mention 7.5 IRE! Typically, these settings are for you to tell the software 
whether or not your digital-analog converter will convert levels properly. This is 
because the software waveform monitor cannot figure this out on its own. It does 
not know whether or not the analog levels are correct.

> Le 20-11-19 à 19 h 31, Andrew Randrianasulu a écrit :
> > В сообщении от Friday 20 November 2020 03:33:10 Pierre autourduglobe via Cin написал(а):
> >> I just checked under Cinelerra-CV 2.3...
> >>
> >> The display has the same calibration problems. The white square is not
> >> displayed at 100 IRE.
> >>
> >> Contrary to the CinGG Waveform there is the option (identified "Y'CbCr")
> >> to display two horisontal lines corresponding to the levels 7.5 and
> >> 92(?) IRE.
> >>
> >> Unfortunately even these lines do not seem to correspond to the values
> >> displayed by the Colors bar.
> > Does ffmpeg's filter work as intended?
> > 
> > https://trac.ffmpeg.org/wiki/WaveformMonitor
> > 
> > if yes, we probably can look how it works rel. to Cinelerra's .....
> > 
> > 

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