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#apertus IRC Channel Logs

2018/06/18

Timezone: UTC


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Bertl
morning folks!
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anuejn
morning!
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Bertl
off for now ... bbl
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se6astian|away
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16:44
se6astian
meeting in 16 minutes
16:50
supragya
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16:56
supragya
hi BAndiT1983
16:57
ArunM
helloo
16:57
supragya
hi
16:58
BAndiT1983
hi supragya
16:58
supragya
was wondering if there is a non fuse mlv2cdng convertor
16:59
supragya
except mlvfs
16:59
BAndiT1983
ask g3gg0, but i doubt it a bit
17:00
supragya
tried running fuse... it exits
17:00
BogdanXOR
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17:00
BAndiT1983
have you looked into logs?
17:00
supragya
did you check the strace logs?
17:00
supragya
i sent g3gg0 i guess
17:00
supragya
wait
17:00
g3gg0-mobile
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17:01
g3gg0-mobile
Hiho
17:01
se6astian
hello!
17:01
nmdis199-
Good evening everyone :)
17:01
ymc98_1
hello
17:02
supragya
hi g3gg0-mobile
17:02
supragya
hi se6astian, nmdis199-
17:02
nmdis199-
Hey, supragya! :D
17:02
supragya
g3gg0-mobile: where in strace logs did you find the fuse exiting?
17:03
supragya
could you point me to it?
17:04
g3gg0-mobile
I am on mobile. The main process exited iirc just after calling mount (ret 0) and some fstat stuff
17:05
g3gg0-mobile
Thats why i wanted to know if any fuse fs worked on your pc
17:05
supragya
it shows no error
17:05
se6astian
ok, lets start the meeting, same procedure like every week, please send me a direct message now if you want to report/discuss/share your progress and I will put speakers in order
17:05
supragya
even on clean distro install
17:05
se6astian
afterwards we can again do the general/misc discussion
17:09
se6astian
anyone? :) I did not receive any messages so far
17:09
supragya
let me begin
17:10
supragya
shall I?
17:10
se6astian
nmdis199-: is first
17:10
se6astian
please go ahead
17:10
se6astian
then supragya
17:10
supragya
okay NP!
17:11
nmdis199-
Okay, so last week I was out of town due to some family stuff. After returning I started reading more on waveform tool (as it's my next task) and working on it
17:11
nmdis199-
I've got an idea as to how to proceed towards it, but it definetly needs to be discussed.
17:12
nmdis199-
I talked to Bertl today, and now we have decided to work on two tests and waveform tool
17:12
nmdis199-
Hopefully the tests should be ready to be presented really soon. That's all I guess
17:13
se6astian
can you go into more detail with tests and waveform tool please? sounds very interesting!
17:13
nmdis199-
Yes, sure.
17:14
nmdis199-
So, I've been reading about waveform tool, and I've found that there are two kind of waveform tool we can work upon, first is luma waveform and second is rgb parade
17:15
nmdis199-
Currently, I am trying to focus on luma waveform , So, I am planning to read a file and then seprating the RGGB channel, once they are seperated I can use the formula for luminance which is
17:16
nmdis199-
0.299*red+0.587*green+0.114*blue
17:17
nmdis199-
So, that's how I am planning to obtain luminance, Bertl suggested me today to compare the float calculations with an integer/fixed point version
17:17
nmdis199-
and calculate the time
17:17
se6astian
sounds good, do you reduce the number of values as well eg. by averaging pixel blocks?
17:18
nmdis199-
One way that we discussed (not related to this test though) was to skip lines , but I am not sure if I should skip lines here
17:18
nmdis199-
averaging pixel blocks is a nice idea!
17:19
se6astian
skipping is simpler I guess so I would indeed first try skipping lines/coloumns
17:19
supragya
A question: may I?
17:19
se6astian
if that works you can test if averaging significantly changes results
17:19
nmdis199-
Yes, it is simplar and it reduced time to 0.010 on beta from 0.4s
17:20
se6astian
do you visualize the waveform somehow currently or is it just a data matrix?
17:20
nmdis199-
I didn't understand? Do you mean if I am planning to plot it ?
17:21
se6astian
the software is a commandline tool currently that outputs data to a file if piped right?
17:21
nmdis199-
yes
17:22
se6astian
right, it would be interesting to plot/visualize the results somehow
17:22
nmdis199-
Yes, I am trying to find a way. There's an organization called kdenlive, they have successfully made a waveform tool. They used Ot library for plotting the waveform
17:22
nmdis199-
Qt*
17:23
se6astian
maybe start simpler and use http://www.gnuplot.info/ ?
17:23
nmdis199-
Interesting, I will read that
17:23
se6astian
or gplot: http://gplot.sourceforge.net/
17:23
nmdis199-
Any more suggestions? I guess I can use some extra information :)
17:24
se6astian
a luma scope looks like this: https://helpx.adobe.com/content/dam/help/en/speedgrade/using/image-analysis/_jcr_content/main-pars/image_5/lumawaveform.png
17:24
se6astian
that is an entire image
17:25
se6astian
it might be useful to just show one line, one coloumn or a crop area of the image though
17:25
se6astian
plotting the data of one line with gplot or gnuplot would be a good start task I think
17:25
nmdis199-
Hmm..I agree. I think I should go with one line/one column and then to a cropped area.
17:25
se6astian
perfect
17:25
se6astian
lets see where that takes you :)
17:25
g3gg0-mobile
Vectorscope :D
17:26
nmdis199-
Yeah :D
17:26
se6astian
great, many thanks for the report
17:27
se6astian
anything else to add? otherwise supragya would be up next
17:27
nmdis199-
No, I think that's all :)
17:27
nmdis199-
Beside, I guess supragya had something to ask?
17:27
supragya
Don't RGB parade and waveform have different tasks to fulfil?
17:28
supragya
one for color "balancing", one for contrast etc
17:28
supragya
so, don't we need both?
17:28
se6astian
yes, one thing after the other :)
17:28
nmdis199-
Yes, we would definitely.
17:28
g3gg0-mobile
Yep exactly
17:28
supragya
ah... I thought... waveform was chosen over parade
17:29
supragya
nvm...
17:29
supragya
So, my task stems from PLR discussion we had
17:29
supragya
Basic thought is to now have a sampled out LUT to translate the 12 bit RAW into appropriate color space
17:30
supragya
*appropriate bit space
17:30
supragya
and for this, I had been looking over .cube and .look formats
17:30
supragya
Are we using something like a .look in camera?
17:31
se6astian
not yet
17:31
supragya
In any case, the idea is that this sampled LUT will be added to a DNG file
17:31
se6astian
the camera currently doesnt support 3D luts, but rather 4x1D LUTs
17:31
se6astian
yet
17:31
supragya
and the raw 12bit PLR data dumped as it is.. I guess
17:32
supragya
3x1D... i have heard 4x1D for R,G,G,B?
17:32
se6astian
monitors or hdmi recorders do support 3D luts mostly though
17:32
se6astian
4x1D for R,G,G,B <- exactly
17:33
supragya
hmm, so I am currently looking at two things... 1 is to discuss with you on how to take the LUT out (you talked about sampling etc, iirc)... g3gg0 says it should be mathematical
17:33
supragya
But when I read your PLR experiment page
17:34
supragya
I thought that sampling would be better to create a LUT
17:34
supragya
for that, I have to think how to add such block in the MLV... (do we have a LUT block in MLV, g3gg0)?
17:34
g3gg0-mobile
Not yet
17:35
supragya
after this, we will have to add a few changes to our recording software and the publisher (which is a mlv->CDNG convertor) so that LUTs can be written
17:35
supragya
currently, I was analyzing a few CDNGs and found their LUTs have non standard behaviour
17:36
supragya
some were using 3d Luts
17:36
supragya
never saw one with 3x1D lut (is it possible in DNG)?
17:36
supragya
some were stored in IFD0, some were in something called a SUBIFD
17:37
supragya
and these changes made photoshop read a DNG and not read others
17:37
supragya
so DNG needs to be analyzed more I guess
17:37
supragya
(any ideas on IFD0 and SUBIFD)?
17:37
g3gg0-mobile
Then you are in the guts of DNG in real world scenarios :)
17:38
se6astian
does the dng standard document contain any information about these tags?
17:38
supragya
another approach could be to add a lut just like any other header by modifying existing code of mlv2dng convertor and then test using exiftool
17:39
BAndiT1983
dng have sometimes a preview image, like JPG, embedded, are you sure that you just have one data slot?
17:39
supragya
but i am not sure if this way is good or hacky
17:39
supragya
se6astian: DNG specifications just provide us with appropriate tags and give no further info... on the step size info, lut type etc etc
17:40
se6astian
https://www.adobe.com/content/dam/acom/en/products/photoshop/pdfs/dng_spec_1.4.0.0.pdf
17:40
supragya
Opening a DNG to analyse using hexeditor is a nightmare
17:40
se6astian
right
17:40
BAndiT1983
exiftool and specs should be enough, wrote so the loader back then
17:40
BAndiT1983
and of course this -> https://www.awaresystems.be/imaging/tiff/tifftags.html
17:41
BAndiT1983
https://sno.phy.queensu.ca/~phil/exiftool/verbose.html
17:41
BAndiT1983
also check verbose option for partial hex dump
17:41
supragya
g3gg0, can mlvfs be changed to non FUSE solution?
17:42
supragya
Using it already BAndiT1983! the exiftool
17:43
supragya
That all the things for my side btw...
17:43
g3gg0-mobile
I am sure the code for dng is a derivate of the mlv tools around
17:44
supragya
also, g3gg0-mobile, did you look at build logs for mlvfs? it complaint of HDutils
17:44
g3gg0-mobile
So you should be able to reuse the code for opening a mlv directly with a small wrapper
17:44
supragya
something to worry about>
17:44
se6astian
thanks supragya!
17:44
g3gg0-mobile
As soon i am back from office
17:45
g3gg0-mobile
About dng...
17:45
supragya
g3gg0-mobile: a few reference links to docs and relevant code from where to branch of would really help me
17:45
supragya
*off
17:46
g3gg0-mobile
The spec defines a lot. There are various ways how to put tags into a dng and depending on the tool you use to open them, your results may vary
17:46
g3gg0-mobile
Some tools only accept sruff in a xml sidecar etc
17:46
g3gg0-mobile
*stuff
17:47
g3gg0-mobile
Will send you links
17:49
supragya
thank you
17:49
se6astian
right, anyone else with a report?
17:50
ymc98_1
Shall I?
17:51
se6astian
yes please
17:53
ymc98_1
I designed an encoded random generator using 8b10b and lfsr for the machxo2. Also a receiver which decodes and counts wrongly transmitted bits for the machxo2. Yet to perform timing analysis
17:54
ymc98_1
I have looked into various packet protocols. That's about it.
17:56
se6astian
great, many thanks
17:57
se6astian
anyone else?
17:57
se6astian
otherwise this concludes this weeks meeting
17:57
se6astian
we can again start general topic discussion, chat :)
17:58
se6astian
thanks everyone for your energy, time, patience and contributions!
17:58
supragya
hmm, se6astian, could you explain how would you go forward
17:58
supragya
with getting the PLR LUT?
17:58
supragya
from the camera?
17:59
supragya
or... how do you think this system that we discussed should proceed?
18:00
se6astian
since the measurement approach is likely easier to start with I would create a script that runs on the zbox that attempts to capture a general luminosity response curve
18:01
se6astian
you can assume the light conditions to be constant
18:01
se6astian
the remote beta is pointed at a color chart
18:01
supragya
was just checking if it is feasible
18:02
supragya
practically
18:02
supragya
(to get this LUT)
18:02
se6astian
basically you can create an imagemagick script that crops a 64x64 image from the full image, averages the 64x64 pixels
18:03
se6astian
then you can vary the exposure time and plot the resulting average value against it
18:03
se6astian
that gives you a simple response curve
18:03
se6astian
then you can add a PLR kneepoint and see if the response curve bends
18:04
se6astian
that is the basis for a simple test lut I would say
18:04
se6astian
does that sound feasible?
18:05
supragya
https://wiki.apertus.org/index.php/PLR, help me with this to visualise, once I have a graph or a response curve as you say,
18:05
supragya
how do I get a lut?
18:08
se6astian
we want the lut to linearize the input right?
18:09
supragya
yes
18:09
g3gg0-mobile
Generating a lut wasnt the main task for the raw video container task;)
18:09
se6astian
ah
18:10
se6astian
maybe just a fake lut would be enough then?
18:10
g3gg0-mobile
So making one for testing purposes would be cool, but not essential
18:10
g3gg0-mobile
I thing the measurement would require some time that is precious
18:11
g3gg0-mobile
Think (damn auto correction)
18:11
se6astian
fake lut basically being just any desired curve you fancy that will alter the values in a verifyable way
18:11
supragya
I just wanted to know what are the boundaries right now... for the project per se
18:11
supragya
that's all
18:12
g3gg0-mobile
E.g. Swap R and G
18:13
g3gg0-mobile
Its a good thing to go deep and check if you inderstand things well and if the container format and the tools support your idea. Doing some Tests with it will be enough
18:13
supragya
Will try doing a few things...
18:13
g3gg0-mobile
So yeah, fake a lut is good enough
18:14
g3gg0-mobile
(still i like your wish to know how things work)
18:14
supragya
I'll try dropping maybe a channel using luts
18:14
supragya
so that maybe the image is pure magenta
18:14
supragya
(yukk)
18:15
g3gg0-mobile
Yeah or invert or swap channels
18:15
g3gg0-mobile
Swapping and inverting proves more functionality
18:15
g3gg0-mobile
Zeroing doesnt prove that e.g. Scaling is right
18:16
supragya
our synthetic frames in mlv creation do not reference any raw12 to build mlv
18:16
supragya
it is all zeroed up
18:17
supragya
to start off with this procedure, we need to make sure that some legit data is in the mlv vidfs
18:17
supragya
that may take some time by itself... or some synthetic frames can be generated
18:17
supragya
like the broadcasting bands
18:18
supragya
*broadcast color bars
18:18
supragya
https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/SMPTE_Color_Bars.svg/1200px-SMPTE_Color_Bars.svg.png
18:18
g3gg0-mobile
I personally would start with real data
18:19
supragya
should i spend some time generating such mlv
18:19
supragya
or take up mlv that is already available in samples?
18:19
g3gg0-mobile
Then dump that one using mlv_dump
18:20
supragya
Then dump that one using mlv_dump: this means MLV -> [MLV_DUMP] -> CDNG (and i have to work on modifying the MLV_DUMP?
18:23
supragya
you may provide details using the emails g3gg0-mobile, I would need to leave for now
18:24
supragya
Good day!
18:24
supragya
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18:24
g3gg0-mobile
Ok
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