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#apertus IRC Channel Logs

2014/10/12

Timezone: UTC


22:50
danieel
america :)
22:59
intracube
$400 for a FLAC audio player?
22:59
intracube
mmm
23:12
aombk
no its not a flac player
23:13
aombk
it plays 192 kHz/24 bit files
23:13
aombk
that you but from a special online store
23:15
aombk
probably converted from lower khz
23:19
seku
well, if the DAC and headamp were world-class ... it'd interest me more than higher-than CD bitrates. even then, carrying damn expensive IEMs or headphoens around is scary
23:20
seku
and you dont want too good sounding headphones. at least not at work. stopped bringing my shure IEMs because they distracted me too much with good-sounding music.
23:20
intracube
aombk: buried on that kickstarter page "The PonoMusic.com Store uses FLAC (Free Lossless Audio Codec) audio format as its standard, for compatibility"
23:21
seku
well, FLAC is the most sensible choice
23:21
Q_
192 kHz / 24 bit does not make sense for playback.
23:21
danieel
96/24 would be enough...
23:21
seku
audiophily is rarely making sense.
23:22
intracube
48kHz would be enough for most
23:22
Q_
40 kHz / 16 bit is enough.
23:22
aombk
intracube, that makes sense. i meant it is not just flac. it supports 192/24 too
23:22
seku
flac can be what you want. got some 5.1 192khz/24bit FLAC tracks here
23:22
seku
and other strange stuiff
23:23
danieel
well i can hear the difference between that 44/16 and 96/24 :) so i prefer the better resolution
23:23
Q_
No you can't. What you probably hear is a problem in your equipment.
23:24
aombk
https://www.indiegogo.com/projects/the-core-wireless-speaker-system
23:24
danieel
gear for 192k is not so common (its more like Alexas)
23:25
seku
danieel, i feel i can hear it sometimes, but i wont ever do a blind test on that :D
23:25
danieel
i have a demanding content... my wife does classical/opera :)
23:25
seku
mostly, 24/96 are mastered for a more discerning public. so they do sound nicer.
23:25
seku
but might sound just as well on 44.1 ... if mastered well
23:26
Q_
I won't be claiming that for recording it doesn't mater, but it doesn't for playback.
23:26
seku
about speakers, ill stick with my linkwitz orions :
23:26
aombk
apertus should have had this approach. having people trying to communicate what a great experience they had with alpha
23:26
seku
http://www.linkwitzlab.com/orion_us.htm
23:27
danieel
playing back a compressed dynamic range is very noticable, with such high dynamic range as opera... yes one can do that to fit into a CD, but it is far from reality
23:27
aombk
"axiom alpha felt like nothing before!"
23:27
seku
mh, i dunno, the dynamic part of the cd sounds fine... mostly the speaker limits... imho
23:27
danieel
so with 96k/24 i am perfectly fine. It is as reality. but if you do not have any match how the content should sound like, you can be fine with a mp3 :)
23:28
Q_
The DR of 16 bit is higher than your ears.
23:28
seku
good ole nyquist
23:29
Q_
And you need the music very loud to be able to hear much above 16 kHz.
23:29
seku
the frequency range barely is, at 22khz... but i dont hear up that high anyway. and nothing interesting there either
23:30
danieel
seku: nice orions... i have a pair of vxt8 by krk
23:30
seku
aah monitors, nice \ufffdD
23:30
seku
:D
23:30
seku
got some B%W as my computer speakers.... love them too :)
23:31
seku
one day, when i save up enough money, ill go for nautilus probably. them snails. love them snails.
23:31
troy_s
Q_: Agree. The old argument is just misplaced.
23:31
troy_s
Q_: the very same ridiculousness abounds in imaging. The bit depth is required for manipulation, not output.
23:31
Q_
troy_s: Exactly.
23:32
seku
you can upgrade a crazy amount in speakers, amps, DACs, i still use CDs for most of my stuff
23:32
troy_s
Q_: Same sort of statements. Almost identical. Same misinformation.
23:32
seku
well, FLACed cds via EAC
23:32
troy_s
I had a fellow try to insist that there was a difference in the signal (digital) going across silver.
23:33
troy_s
And that was where I realized the monstrosity I was talking with.
23:33
Q_
Not to mention that most recent music doesn't even have a decent dynamic range, it's all been compressed.
23:33
aombk
audiophile magazines still do recordable cd reviews
23:33
troy_s
Q_: Why stop there? Aesthetics are emergent.
23:33
seku
hehe, silver crypgenic cable?
23:34
seku
i also had an argument with a guy about speaker cables and interconnects ( my point : if cables sound differently, then the cable is badly designed)
23:34
aombk
cd audio quality reviews
23:34
seku
was a bit ugly
23:34
troy_s
There is a professor that has done unscientific questions on MP3 vs lossless. Over the years (not surprising) his students have come to prefer MP3
23:34
Q_
troy_s: The only good argument I've ever heard for quality of digital cables is the bit error rate.
23:35
troy_s
Q_: Point is: You hear it rather obviously.
23:35
troy_s
It isn't like a subtle timbre. LOL
23:35
seku
well, there is a concern for Jitter in digital cables. but that can be adressed nicely by asynch buffers
23:35
aombk
blind a/b testing is always the answer
23:36
seku
i admit tho that DAC upgrades can make a difference.
23:36
troy_s
It isn't magic though. You can hear digital oopsies as they are glaring. Not some unnoticeable qualia.
23:36
troy_s
DACs of course!
23:36
troy_s
Hence the D to A part.
23:36
troy_s
But even then in the contemporary market it is hard to argue against massive vendors like Burr B or Wolfson...
23:37
seku
i'm with Sabre :)
23:37
Q_
seku: Yes, once you get from digital to analog, all the analog parts get important again.
23:37
seku
ESS32
23:37
troy_s
It is equivalent to someone trying to manufacture thresholds that Apple does in a mom and pop shop. Virtually impossible.
23:37
seku
Q_, thats why my DAC also does preamp duties, and then feeds active speakers
23:37
troy_s
Their tolerances are a byproduct of scale.
23:38
seku
(anedio DAC2) ... cute little thing
23:38
troy_s
Anyways... I am ghetto in audio.
23:38
seku
doesnt sound that way, troy_s :)
23:38
troy_s
But I totally comprehend the foolishness over bit depth.
23:39
troy_s
seku: I am. I have some older school decade old stuff. Holds up fine. Newer consumer receiver.
23:39
seku
thats all that matters :)
23:39
troy_s
I have toyed with bumping up to Paradigms but alas... Hard to justify.
23:39
comradekingu
There is a difference in silver, it will have slightly better rise and fall times for the same quadrant because it concucts slightly better
23:40
danieel
at audible frequencies?
23:40
troy_s
In Analog sure.
23:40
comradekingu
I dont see the point to be argued though
23:40
troy_s
Digital? I call bullshit.
23:40
troy_s
Digital transmits just fine down a fricking coat hanger.
23:40
seku
common audiophily "wisdom" states that silver sounds faster, and more brittle.
23:40
comradekingu
You can measure it with an oscilloscope if you want
23:40
comradekingu
Im not arguing it doesnt
23:40
seku
me? im using well-shielded copper
23:40
troy_s
Hell, I could scream beeps and boops out at you.
23:41
troy_s
LOL.
23:41
troy_s
Granted it would be a slow transmission...
23:41
seku
wait, let me get you a link
23:42
troy_s
I am sure the various metals may have measurable differences in analog though. No clue nor interest how buried that ends up though.
23:42
Q_
Doesn't using silver and gold actually cause more noise because of their difference in electrode potentional then the copper?
23:42
seku
this is one of those crazyheads : http://www.hoererlebnis.de/archive/pdf/059-mk-phonosophie.pdf
23:42
comradekingu
They do, and gold is worse than copper
23:43
seku
selling interconnects and power cables as upgrades
23:43
seku
for thousands
23:43
comradekingu
So if you ever see someone with expencive cables tell them they will do better by soldering the cables in without gold terminals
23:43
troy_s
Interesting.
23:43
Q_
I don't think I ever saw XLR cables with gold contacts.
23:44
troy_s
But obviously it is sub Nyquist or whatever in digital land?
23:44
seku
just use good Neutriks and youre fine
23:44
seku
(case in point : mine are soldered)
23:44
troy_s
Q_: How come? Does the difference generate voltage or?
23:44
Q_
troy_s: Yes.
23:44
Q_
troy_s: Battery principle.
23:45
troy_s
Genius.
23:45
Bertl
actually thermocouple
23:45
troy_s
Oh oh... Nerd alerts.
23:45
troy_s
That is quite fascinating.
23:45
comradekingu
the cable is an inductor, with resistive properties going along it, then a capacitive effect in between the wires
23:46
troy_s
Am I to guess that consistent mediums are important then?
23:46
comradekingu
Q_: all the neutrik XLRs have gold contacts afaik
23:47
troy_s
comradekingu: So what is the net sum of difference between capacitive / inductive is a differing voltage and noise?
23:47
Q_
comradekingu: Looking at their website, none of their XLR connectors have it.
23:48
comradekingu
troy_s: if your cable isnt broken/underdimensioned then nothing
23:48
Q_
Oh, some do.
23:48
troy_s
comradekingu: But if you have a context where there is a differential in the voltages?
23:48
seku
well, if one day i win the lottery, i will get me these : http://www.htguide.com/forum/attachment.php?attachmentid=12520&stc=1&d=1211369490
23:48
comradekingu
External noise can make a difference, where balanced cables help
23:48
aombk
acoustic room treatment is much more important on the sound you hear than those technical matters
23:49
seku
these will make CDs sound really nice... if nicely recorded
23:49
aombk
and it is almost never being done properly
23:49
comradekingu
troy_s: there is always a difference, but is academical
23:49
troy_s
Nyquist levels yes?
23:49
troy_s
Below them?
23:50
comradekingu
Nyquist levels determine a frequency, so then you are using a cable dimensioned which has to be non-broken
23:50
troy_s
All quite interesting stuffs.
23:50
troy_s
Dark alchemy.
23:51
troy_s
Some of the most interesting imaging code is frequency domain stuffs.
23:51
comradekingu
Its not alchemy at all, its plain math
23:51
comradekingu
Anyone trying to tell you different is also a cable-salesman
23:51
troy_s
Alchemy. It is lower than the floor of my understanding. ;)
23:52
aombk
the important thing to remember is. someone got 6mil. funding because he persuaded neil young to persuade his friends to say a few nice words about the "feeling" this portable flac player gives you
23:52
aombk
like vinyl!
23:52
seku
too many salesmen and not enough listeners in the industry tho :(
23:52
troy_s
seku: Again, aesthetics are emergent. :)
23:52
aombk
it probably has a stereo image expander built in
23:53
troy_s
To be fair to vinyl, the vinylistas have a valid point on one vantage; most vinyl is mastered very differently to generic MP3s
23:54
troy_s
And that mastering can outweigh the image disparity.
23:54
troy_s
Perhaps more so these days, where vinyls are limited / exclusive releases
23:55
comradekingu
*otherwise
23:55
troy_s
comradekingu: ?
23:55
aombk
i knew i shouldnt post these links :P
23:55
comradekingu
i was in err, and returned to have my offset corrected
23:56
troy_s
I have entirely failed to comprehend even one word of a sentence online. Again.
23:57
comradekingu
The joke is you need to align the offset of your cd-rom otherwise you cant rip CDs with matching filesums
23:57
wescotte
joined the channel
23:58
comradekingu
brb sometime later
23:59
troy_s
Bertl: how goes the plan?
23:59
Bertl
forward
00:00
troy_s
Bertl: Did the EOS mount hit funding?
00:01
Bertl
what do you mean with 'hit'?
00:04
seku
the active mount? barely hit funding.
00:05
seku
was at 120k :)
00:05
seku
well gnight, bedtime
00:07
Bertl
night!
00:08
troy_s
Bertl: Reached goal. That is a helluva lot of work.
00:09
Bertl
ah, yeah, well, we'll see :)
00:09
troy_s
Bertl: Seeing as how the first milestone appears to support two sensors, any chance of a file moniker when you get to raw? As in a teeny file indicator somewhere in the blob?
00:10
troy_s
(I know... Discussed previously.)
00:10
Bertl
we will most likely use the MLV format, which supports a lot of metadata
00:10
troy_s
Ugh
00:10
Bertl
it is well structured, and there is already good support
00:12
danieel
which sw supports mlv? i do not recall any grading suites to open these...
00:12
troy_s
Ugh
00:12
troy_s
Where is the spec?
00:12
troy_s
Correct
00:12
troy_s
Going to piss off an entire audience base overnight
00:12
danieel
as for metadata, even in dng you can have proprietary data islands, if that is your target :)
00:13
seku
afaik mlv was born out of the misery of Canons firmware : the format needed to index a lot of out-of-order data and save it correctly to the limited speed of a 100mbyte/sec CF card
00:13
g3gg0
hi
00:13
seku
hi g3gg0 , you can explain that way better than i
00:14
troy_s
(Not to knock a decent format of course... But plays well with others is a pitfall.)
00:14
troy_s
Where is the spec though? And a sample?
00:14
troy_s
(Bayered ideally)
00:15
seku
afaik grading suites are mostly fine with CinemaDNG. compressed cinemadng would be even nicer :)
00:15
g3gg0
mlv was born because there is no format that would support raw bayer data without having to tweak on several points
00:15
troy_s
g3gg0: Spec and sample?
00:16
g3gg0
please dont rush
00:16
troy_s
LOL
00:16
troy_s
I wasn't aware I was. Apologies.
00:16
g3gg0
its already late and it takes a few seconds
00:16
troy_s
I just would like to try and see if I can get an OIIO stub working
00:17
g3gg0
https://bitbucket.org/hudson/magic-lantern/src/4d5cf113a68128c866eb788cd7ea3245e81fcc34/modules/mlv_rec/mlv.h?at=mlv_rec_lj92
00:17
g3gg0
thats the format as header
00:18
g3gg0
https://docs.google.com/spreadsheet/ccc?key=0AgQ2MOkAZTFHdHJraTVTOEpmNEIwTVlKd0dHVi1ULUE&usp=drive_web#gid=1
00:18
troy_s
Thanks.
00:18
g3gg0
thats some more detailed explanation
00:18
g3gg0
this was the base before the header was created
00:19
troy_s
So RTC is a time code chunk?
00:19
g3gg0
we used to edit it that way before creating some headers that could be used to build the files
00:19
g3gg0
RTCI is the real time clock information
00:19
troy_s
Okie.
00:20
g3gg0
every (meta)data block has a µsec timestamp
00:20
troy_s
I wonder if we can generate a simulated MLV using CMV12000 data.
00:20
g3gg0
sure
00:20
g3gg0
very simple
00:21
g3gg0
[MLVI] [RAWI] [VIDF]
00:21
troy_s
First is header?
00:21
g3gg0
yep
00:21
troy_s
Second data blob?
00:21
troy_s
Third...
00:21
g3gg0
RAWI = RAW information
00:21
troy_s
Yep
00:21
g3gg0
dimensions, depth etc
00:21
g3gg0
VIDF= video frame
00:21
troy_s
Oh OK.
00:21
troy_s
So a metadata.
00:22
g3gg0
yep
00:22
troy_s
Is the meta variable length?
00:22
g3gg0
MLVI appears on every file at offset zero
00:22
troy_s
(I have an OIIO stub already for the raw CMV12000 shots that loads fine in my lab thingy.)
00:23
troy_s
Rawi is fixed too?
00:23
g3gg0
all blocks basically support variable length. for most blocks it wont change though. only INFO blocks that contain ascii text are variable iirc
00:23
g3gg0
all blocks share the same format
00:23
troy_s
g3gg0: So is this a V1 or pre-v1 implementation?
00:24
g3gg0
?
00:24
g3gg0
v1?
00:24
troy_s
Version one. How stable?
00:24
troy_s
I expect there is a 1.1 or something likely for Axiom
00:24
g3gg0
this is v2.0
00:25
troy_s
g3gg0: In your estimation then, how much would potentially (guess) shift to support Axiom?
00:25
g3gg0
for axiom - as bertl explained - there would be an addition to support raw data that is not going from TL to BR, but that is written as stripes
00:25
danieel
g3gg0: the structures are LE or BE ?
00:25
g3gg0
LE
00:25
troy_s
Temporal stripes?
00:25
g3gg0
spatial
00:26
troy_s
So unordered?
00:26
troy_s
But same frame?
00:26
g3gg0
iirc bertl explained that the sensor data isnt read out from left to right, but its sectioned and interlaced
00:26
troy_s
Right. So same temporal frame, but shuffled batches.
00:27
Bertl
the idea is to allow for recording sensor data without reordering it
00:27
troy_s
And dumping accordingly frees up processing.
00:27
g3gg0
this format isnt explicitely supported by the format's metadata yet. i.e. the writer cant tell the reader how the data is ordered.
00:27
danieel
come on, you can do that little shuffling in the fpga
00:28
Bertl
yes, we do it in the FPGA already on the Alpha
00:28
danieel
so why not on beta?
00:28
troy_s
It is like having the old guys shouting from the muppets.
00:28
Bertl
but if you want to maximize battery for example, you don't want to do that
00:28
troy_s
Ah. Good point.
00:29
g3gg0
MLV sample files: http://magiclantern.fm/forum/index.php?topic=11899.msg130484#msg130484
00:29
troy_s
Not that batteries are a tremendous issue given the contexts. But still valid.
00:29
troy_s
g3gg0: What sensor there though? Those raws?
00:29
Bertl
or reduce heat :)
00:29
g3gg0
14bpp canon eos
00:30
troy_s
g3gg0: is there any lab processing software out there right now for the MLV format?
00:30
g3gg0
to use tools like mlrawviewer from chmee, i recommend to stick to 14bpp formatting until he added variable width
00:30
g3gg0
you mean for debugging the format?
00:30
troy_s
I do like the leaner idea of MLV. OpenDNG has a pig of crap in it.
00:31
g3gg0
yeah thats one reason for mlv.
00:31
danieel
g3gg0: future additions shall include multi-stream (frame based hdr), multi roi support (to tag the parts) and possibly specifying dense bit packing.... the nonstandard application specific striping makes little sense
00:31
seku
mlv also converts fine to cinemadng.
00:32
troy_s
Hrm. I wonder what he(?) Is using for DNG reading.
00:32
troy_s
Probably a tiff hack.
00:32
danieel
what dng does better is to tag the optically black areas - you might want to do that too
00:32
g3gg0
danieel: can you note that somewhere (wiki, forum) for discussion?
00:32
danieel
copy it yourself. i will not repeat myself :)
00:33
seku
me? using chmee's raw2cdng
00:33
troy_s
danieel: Optically black?
00:34
troy_s
Who is the author of MLRawViewer?
00:34
g3gg0
danieel: uhm its half past two and i am typing from my phone in bed. maybe i cannot remember every detail you wrote.
00:34
danieel
g3gg0: is there any indexing for quick seeking?
00:34
danieel
pm my email, will copy it there and you can sort it out tomorrow
00:34
g3gg0
troy_s: baldand, andrew baldwin
00:34
danieel
*me
00:35
g3gg0
danieel: .idx files containing a header and only mlv_xref entries
00:36
g3gg0
danieel: any reader application may store those .idx for later processing or recreate on its own
00:38
troy_s
Interesting. He wrote the tag parser.
00:40
g3gg0
troy_s: baldand?
00:41
troy_s
Yes
00:45
g3gg0
troy_s: main goal for MLV was to get the raw data out of the camera as quick as possible, with no preprocessing except cropping out of the full frame and as much metadata as possible. converting to interchange formats like CDNG is stuff for a workstation
00:45
troy_s
g3gg0: It's a decent enough goal, but the overlap in the design is questionable to skip.
00:46
troy_s
g3gg0: Debatable of course.
00:46
g3gg0
many tools are very picky about CDNG.
00:46
g3gg0
yeah
00:46
troy_s
g3gg0: I've sort of been plucking away on a lab software because I'm interested in getting footage into an offline state, so dealing with the demosaic etc. is useful.
00:47
troy_s
g3gg0: But he has a LUT support in there, so you are almost into the one-stop-shop for editorial... might as well take it that last 2% IMO.
00:47
troy_s
g3gg0: A few things that can be imrpoved almost immediately is tacking on OCIO and OIIO support. Gains you offline dumping to EXR / DPX immediately and full LUT / color support.
00:47
danieel
g3gg0: send few extras to think about
00:47
danieel
*sent
00:47
troy_s
g3gg0: But I am just looking at his code.
00:48
troy_s
I haven't looked at amaze much. I probably should. I need to start doing RMSEs on generated bayers and see which ones hold up ideally.
00:49
g3gg0
OIIO sounds interesting, never tried though
00:49
troy_s
g3gg0: OCIO and OIIO are reference standards really.
00:50
troy_s
g3gg0: And about as dead easy to implement. With python bindings.
00:50
troy_s
I'd be skeptical of the shader code
00:50
troy_s
OCIO allows for GPU acel.
00:50
g3gg0
as they are already 4 byte names, consider them being perfect MLV tags already ;)
00:50
troy_s
g3gg0: Well adding OIIO gets you TIFF/DPX/EXR immediately, with the latter two being most important.
00:51
troy_s
and OCIO opens up CDL for free.
00:51
g3gg0
i will read into it and check if there is a simple way to add it. thanks for pointing there.
00:51
g3gg0
but its already late, 4h left for sleep
00:51
troy_s
Among a plethora of other useful things. Ideally someone adds in CinemaDNG or OpenDNG to the OIIO base. Mr. Gritz is a god and would surely add it.
00:51
troy_s
g3gg0: Ping me on the morrow.
00:52
g3gg0
will do. good night everyone
00:52
troy_s
Wish my GL were better.
00:52
danieel
gn
00:54
troy_s
Wholly god does the shader code suck in ellipses.
00:54
troy_s
Drives me to the point of being unable to read it. At all.
00:54
troy_s
There has got to be a better way.
00:56
g3gg0
left the channel
01:01
danieel
the shader code is usually ugly, depends what version of the compiler you can use
01:01
wescotte
left the channel
01:01
danieel
opencl is better in that respect, but does not run everywhere
01:06
troy_s
danieel: I've found a decent method to load files. I like the idea of the increased performance, but little things bug me like how to get bit depth etc of the shader.
01:08
danieel
you mean the computational format?
01:22
troy_s
danieel: I guess so. I'd like to know that a shader is operating at 32 bit float for example.
01:27
danieel
should be 32bit (SP)... the DP rating for gpus is 64bit float
01:27
danieel
it depends on the texture format you use
01:28
troy_s
danieel: Just a standard fragment shader. I'm just curious how to enum / query that.
01:28
danieel
make a test to see when it looses precision
01:28
troy_s
No. I won't. There has got to be a query.
01:28
troy_s
That's junk.
01:28
troy_s
Egads.
01:28
troy_s
If that is how you have to test depth, shaders are fricking hopeless. I cannot imagine that is the method.
01:29
danieel
well... in the gpu terminology we can start complaining about dimensions being specified in floats
01:29
danieel
how do you get a pixel perfect mapping from that?:)
01:29
troy_s
I'm cool with that... I just want a query.
01:29
troy_s
Partials I'm cool with.
01:29
troy_s
But I'd like to know what depth I'm at.
01:30
danieel
... texture format
01:31
troy_s
danieel: Any links?
01:36
danieel
the GLSL specs state 3 precisions - highp/mediump/lowp, with no meaning :)
01:37
danieel
section 4.7.2 at https://www.opengl.org/registry/doc/GLSLangSpec.4.50.pdf
01:45
Bertl
unsing floats for dimensions/coordinates isn't a bad idea per se, normalizing them OTOH ...
01:48
danieel
it causes rounding problems...
01:49
danieel
so while a nearest neighbour works, a better interpolation will produce slightly different result
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Bertl
off to bed now ... have a good one everyone!
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aombk
is anyone here?
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07:12
KurtAugust
Goodmorning! Rise and shine.... Question to @ApertusOSCinema Beta backers: would you like it to be designed so you won't need an extra camera cage? Sturdy housing with cable protection and lots of threaded holes. For instance for a monitor. Also strong enough to use it a follow focus and not having any flex (is often difficult with the rubber bases of a dslr). This will of course increase the cost of manufacturing, so I can imagine some
07:12
KurtAugust
developers wouldn't mind something less. I would just think that the added expense is still much less than any aftermarket solution and prolongs the camera's life. And since it's designed as a box anyhow...
07:13
se6astian|away
changed nick to: se6astian
07:15
KurtAugust
Hey, are the irc logs broken?
07:16
se6astian
good morning
07:16
se6astian
indeed the sunday one is empty
07:16
se6astian
I will check it later
07:17
KurtAugust
And I was thinking you finally took some rest.
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KurtAugust
Burglary at Apertus: millions worth of logs stolen!
07:30
se6astian
"a thief copied large amounts of highly scandalous internal communication from the high security server"
07:30
se6astian
ok gotta go :)
07:30
se6astian
need to sell the logs on the black market!
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se6astian
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10:43
danieel
its funny how one spends $100M's on a movie, and at the end it sucks because all the VFX is global shutter like while real scenes got heavy rolling shutter artefacts
10:49
intracube
danieel: movie in question?
10:52
danieel
newest transformers
10:53
danieel
bay's look is no way possbile with rolling shutter cameras
11:04
intracube
danieel: I couldn't see any obvious signs in the transformer 4 trailer
11:24
Bertl
morning folks!
11:35
__anton__
hi, looks like irc archive isn't showing today's log
11:35
__anton__
http://irc.apertus.org/index.php?day=12&month=10&year=2014 is empty for me
11:37
Bertl
indeed, let me check
11:44
Bertl
test
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tyrone_
uhhh this sunday is quiet :-)
12:17
Bertl
nah, the logger ran out of space, is already fixed
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12:18
tyrone_
ahh okey thaks bertl..... the log was looking strange :-)
12:20
tyrone_
bertl do you know if somebody from the apertus team will go to the vision exhibition in stuttgart?
12:37
Topic
apertus° - open source cinema | www.apertus.org | Currently Hot: AXIOM Beta Crowd Funding is Live: http://igg.me/at/axiom-beta | IRC Logs available at: http://irc.apertus.org
12:37
se6astian
has set the topic
12:38
Bertl
test3
12:38
tyrone_
you can talk directly to the image sensor manufactures and much other companys from europe...
12:38
Bertl
okay, logs should be back and working
12:40
tyrone_
last time i was there in i could talk to the person from frauenhofer who has created of the image seonsor for the first digital camera from arri... it was intressting
12:41
danieel
d20 or that 1990's military one?
12:41
tyrone_
d20
12:42
danieel
most of the people working on arri came from frauenhofer research..
12:43
tyrone_
that i didn't know....
12:45
tyrone_
do you know if there is a change with the access from the documents from truesense because on semi has bought them?
12:46
tyrone_
okey it was in april the takeover...
12:47
danieel
probably not, they finished the transfer like a week or two ago
12:52
danieel
do you plan to go stuttgart?
12:53
tyrone_
i hope i can go it's for me just 2h drive so not far away....
12:59
tyrone_
danieel does ON Semi has for the other sensors(example VITA) a NDA for the specification manual or is it public?
13:03
danieel
public, but you could figure that out if you've been actually looking :)
13:09
tyrone_
okey i think i'm stupid :-) i couldn't finde the spec on the site..... google was better....
13:35
danieel
the DS is on the product page :)
13:45
tyrone_
perfect just the vita12k and 16k have a reduced datasheet...... every other one is with full specs even the vita 25k.....
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se6astian|away
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16:33
se6astian
good evening
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16:59
troy_s
danieel: I can check, but pretty sure it was shot on a global shutter camera.
17:11
aombk
well, rolling shutter was not transformers biggest problem
17:11
aombk
*if it was shot whit rolling shutter equipment
17:15
troy_s
Let me be clear... There are no problems
17:15
troy_s
Domestic: $245,435,927   22.7%+ Foreign: $835,500,000   77.3%= Worldwide: $1,080,935,927
17:16
troy_s
When your metric of problem / not problem is money, there are no problems. At all.
17:17
troy_s
That puts it at slot 11 of all time worldwide grosses.
17:17
danieel
troy_s: imdb/technical says red dragon, but the artefact is worse/comparable to what we measured on epic
17:18
intracube
danieel: are there any clips online that show the issue?
17:18
danieel
probably not.. i can take 2 snapshosts if you need
17:18
troy_s
danieel: May have been. You also have to remember that Epics are used when cameras are going to get crunched.
17:19
troy_s
danieel: So any high-action sequence, where high risk to camera, you can almost be certain it is a POS Epic; the Eyemo of the new era.
17:19
danieel
it is most visible in nonvfx action shots (people figting, camera panning quickly), let me find it
17:19
troy_s
And doubly certain on a film where the primary camera is a Dragon.
17:20
danieel
wasnt it supposed to be shot on imax/3d ?
17:20
troy_s
Dragon has a global no?
17:20
aombk
the seccond transformer had compositing problems too
17:20
danieel
no
17:20
danieel
global can be simulated for <180deg with an liquid crystal shutter
17:20
troy_s
aombk: Cannot be avoided. There are tracks that come back from Mumbai with slippage during tracking for example, and if the schedule has slipped, it gets rolled with.
17:21
troy_s
danieel: Rare to shoot under the 180. Is that what they were doing?
17:22
danieel
nope, give me a sec to dump the frames
17:23
aombk
the new red sensor does that thing with liquid crystal shutter
17:23
aombk
actually the new mount
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17:28
aombk
http://s578.photobucket.com/user/rajeshseeni/media/1.jpg.html
17:30
troy_s
Tapered pillars.
17:42
danieel
http://home.rozsnyo.com/hollywood-loves-rolling-shutter.jpg
17:44
intracube
danieel: that is from what film?
17:44
danieel
transformers, age of extinction
17:45
danieel
once you start making a camera, you cant watch movies... RS besides the poor dynamic range is most noticable :)
17:45
Bertl
wb gcolburn!
17:48
intracube
speaking of dynamic range and highlights: http://images.static-bluray.com/reviews/6812_20_1080p.jpg
17:49
troy_s
intracube: Your point?
17:49
troy_s
White and black are creative decisions.
17:50
troy_s
I would hate to see a world where everyone avoids white. See Robert Richardson's earlier work where he blew out with rear nets etc.
17:50
danieel
prometheus was quite good.. was not distracting much
17:51
intracube
troy_s: it's that they didn't avoid it (when shooting) then tried to bring it down in post
17:51
intracube
at least that's what it looks like
17:52
danieel
intracube: if you see the whole movie it had a point.. was set in averagely dark gray, leaving brighter levels for when needed
17:52
danieel
you can adapt your range level to the darks... and then they surprise you with a sun or light...
17:52
danieel
if you keep the mood wide range, you cant do exceptional things
17:52
intracube
danieel: I think you're missing my point
17:53
intracube
it's that the highlights on the upper screens look heavily clipped
17:53
intracube
then they've been brought back to non peak levels where you'd expect to see detail
17:53
intracube
it looks jarring IMO
17:53
danieel
its intentional bring down as i wrote.. but yes, there is lack of detail :)
18:01
intracube
in practice you'd need some frame of renference to peak white
18:01
intracube
so it really depends on the shots leading up to it
18:01
troy_s
Pretty sure the peeps helming know how to shoot. ;)
18:01
troy_s
Just saying'.
18:02
intracube
loves to be an arm chair critic
18:02
troy_s
If at any point someone felt that was a mistake, I can state beyond a shadow of a doubt that particular shot would have been reshot. Nothing to it.
18:03
Bertl
intracube: do you have a nice arm chair?
18:03
troy_s
I will say it again for folks that perhaps didn't grasp / embrace / comprehend:
18:03
troy_s
Aesthetics are emergent.
18:04
troy_s
Could Bertl craft a nice PLE that gathers up a much larger DR? Absolutely. Should a DP throw out all but one stop of it? Absolutely.
18:04
intracube
Bertl: :P
18:05
troy_s
Aesthetics go through the typical cycles of “out of place with purpose” “fresh new bleeding edge” “mainstream” “cliched vernacular”
18:05
troy_s
See Jump Cut.
18:05
troy_s
See Cross Cut.
18:05
troy_s
See cinema as coffee house spectacle, to narrative / non-narrativr
18:06
Bertl
very interesting what I'm saying here?
18:06
troy_s
?
18:06
Bertl
ah, nevermind, window update problem
18:07
aombk
aesthetics are emergent but still, sometimes people, even professionals, dont know what they are doing
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18:11
aombk
and this is very evident and clear in transitional periods, for example analog to digital
18:12
aombk
which in film is, among other things, chemistry to math (the color correction aspect of it)
18:26
troy_s
aombk: Perhaps surprisingly, many high profile projects go out of their way to research before shooting due to the experience front.
18:27
troy_s
So I'll call into question the trope that many professionals “don't know what they are doing”
18:27
troy_s
Mainstream film is the most conservative industry you would ever see. Mistakes are made, heck yes, but in terms of attempting to insulate against them from a shooting vantage? There are many layers.
18:28
troy_s
Everyone from the DP, to assistants, to other HoDs have varying experiences that insulate.
18:29
troy_s
There are many legendary stories from the film era of mistakes too. They happen, but by and large, studios don't generally let Dondald Duck and Mickey helm hundred million dollar projects.
18:32
aombk
research doesnt always reward us with results
18:32
aombk
so you disagree that sometimes people, even professionals, dont know what they are doing
18:34
troy_s
aombk: I am offering my opinion purely as anecdotal from experience. In my personal experience, one can have a gripe with aesthetic choices etc, but I have met very few that “don't know what they are doing”.
18:34
troy_s
And the system is designed against that sort of failure, as there are many layers of insulation.
18:35
troy_s
(EG a DP may be thinner on color knowledge, but has a generally experienced DIT on their side.)
18:35
aombk
maybe we should define "dont know what theyre doing"
18:35
intracube
troy_s: who has said that many professionals don't know what they're doing?
18:35
troy_s
I just think it is an overly simplistic trope peddled by the masses to try and explain Bay-esque choices.
18:36
troy_s
aombk: Exactly. Privileged rubbish terms.
18:37
troy_s
intracube: Scroll back.
18:37
aombk
intracube, i said something like that
18:38
intracube
oh ok
18:38
intracube
wasn't paying full attention
18:39
troy_s
It is just too simplistic to attribute that concept to other complex systems.
18:40
aombk
troy_s, well in the end, i dont agree with you on that
18:41
troy_s
aombk: Sure. Feel free to disagree. There is a smidge of experience behind my anecdotal evidence though.
18:43
troy_s
There is also the very real fact that seasoned veterans are often doing things in mainstream movie making that well... Haven't been done before. So of course they don't know what they are doing.
18:44
aombk
the masses never judge the complex process and the amount of work and research professionals put in to produce something
18:44
troy_s
Sure. But it is also ideological I believe.
18:44
aombk
what is?
18:45
troy_s
If we say “That movie sucked” is is basically a statement of constancy (a myth) and a checksum of extremely complex things.
18:45
troy_s
I cannot count for example, the number of times my opinion on various bits of cinema have shifted and changed. The myth of constancy is a foolish one.
18:46
troy_s
And over time, that constancy is more assaultable. See DW Griffith's earlier cinema for example, which at once is celebrated as monumental feats and also simultaneously grotesquely racist.
18:46
troy_s
Cinematography falling into the precise same zone.
18:47
troy_s
aombk: Sense?
18:48
aombk
yes but i dont know where to start. i disagree to the core of it.
18:48
aombk
are you a dp?
18:49
g3gg0
hi
18:50
troy_s
What core?
18:50
troy_s
Hello g3gg0
18:50
g3gg0
hi troy_s
18:50
troy_s
aombk: What premise lay at the core that you disagree with.
18:50
troy_s
That professionals do or do not know?
18:51
troy_s
There is a huge breadth there, as professional is a rubbish term for anyone that has been paid to ply their body to something.
18:51
aombk
at the core of what you are saying i think lies relativism
18:51
troy_s
Yes. Of course it does.
18:51
aombk
postmodernist relativism
18:51
troy_s
Plato sort of screwed that pooch for us
18:51
troy_s
Indeed.
18:52
aombk
hah well yes, i am not a big fan of this approach
18:52
troy_s
Or in actuality, a vastly more workable model for sociological manifestations? ;)
18:52
troy_s
Sure. But you would have a hard time taking that to the mat with this peep.
18:52
g3gg0
troy_s: if i may ask, whats your background in film making?
18:52
troy_s
Spent too long getting my own belief system dismantled to disagree with it any longer.
18:53
troy_s
g3gg0: Studied film /photography in art school, shot / produced blah blah crap, and also exists as a minion to the machine.
18:54
g3gg0
troy_s: are you behind the cam or mostly post processing?
18:54
g3gg0
just curious
18:54
troy_s
Depends on what I am doing.
18:54
g3gg0
so both
18:54
troy_s
On independent / personal / freelance, sometimes all.
18:55
troy_s
On some projects, such as album covers, sometimes none.
18:56
troy_s
Sadly know an unhealthy amount about colorimetry thanks to epic failures on my end when crafting work. :)
18:56
troy_s
Still trying to learn.
18:57
g3gg0
hehe :)
18:57
g3gg0
so colorspace conversion stuff is one of your competences?
18:58
g3gg0
fought long to understand how to really convert raw bayer data into RGB
18:59
g3gg0
the things behind the scenes. really good to know. then things make a lot more sense
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18:59
Bertl
welcome PRN!
18:59
g3gg0
btw, hi Bertl
19:00
troy_s
g3gg0: Yes sadly.
19:00
PRN
Thanks Bertl
19:00
troy_s
g3gg0: Take chart. Develop 3D LUT, transform to XYZ. Transform to output +/- a Bradford or CAT02 in there. ;)
19:01
troy_s
g3gg0: But of course there are times when you want to only assert a linearized model for manipulation, and operate in the native RGB captures. Keying for example.
19:02
g3gg0
CAT02? ok looking up. the other things i did myself too
19:02
troy_s
Linearized to assert your resultant associated alpha values represent occlusion, and native RGB to avoid crosstalk.
19:02
troy_s
g3gg0: CAT02 is just one of the newest breeds of CA.
19:02
g3gg0
LMS color space
19:02
PRN
anyone from apertus team going to Broadcast India, Mumbai?
19:03
troy_s
g3gg0: All of the best CAs are LMS domain.
19:03
g3gg0
ok is it the one related to XYZ, just with correct chromatic "distance" between colors?
19:03
troy_s
They have to be.
19:03
troy_s
g3gg0: Just a different model. Like a Bradford++.
19:04
g3gg0
reminds me of http://xkcd.com/927/
19:04
troy_s
http://web.stanford.edu/~sujason/ColorBalancing/adaptation.html
19:04
troy_s
Not the same.
19:04
troy_s
This isn't about standards. It is more about attempting to simulate something. So there is a little more directionality.
19:05
g3gg0
thanks for the link. my knowledge mostly is built upon the guides from http://www.brucelindbloom.com/
19:05
troy_s
Bradford superseded Von Kries, as VK superceded XYZ scaling.
19:05
troy_s
And CAT02 / Sharp are further refinements.
19:05
g3gg0
it is also mostly used for white point adaption?
19:05
troy_s
Lindbloom is a canonized beast, with a slight ICC twist to most.
19:06
troy_s
Chromatic adaptation, yes.
19:06
troy_s
Solely.
19:06
troy_s
Although CAT02 is part of a larger thing.
19:06
troy_s
Which is a sort of newer breed of color, being Mr. Fairchild's CIECAM
19:06
troy_s
Color appearance models.
19:07
troy_s
Which attempt to solve some of the more nuanced bits of the psychophysical aspectd
19:07
troy_s
(As in many of the color phenomenon illusiony things)
19:07
g3gg0
ah good to know. thanks
19:07
troy_s
Problem is, some / many may be cultural.
19:08
g3gg0
still the most odd thing is the M_RGB<-XYZ which has to be determined
19:08
troy_s
(See Herskovits et al regarding Influence of Culture on Visual Perception)
19:08
troy_s
(Some postmodern relativism evidence there too for aombk. ;))
19:08
troy_s
g3gg0: Explain?
19:09
troy_s
Matrices will always fall short, and likely have some clusters of colors that suck.
19:09
troy_s
Same goes for display profiling.
19:09
g3gg0
the the camera matrix, for converting XYZ to RGB. the most important thing to get the best images, but still it is being determined by shooting a color patch in sunlight.
19:09
troy_s
Not exactly
19:10
troy_s
That is ICCs lovely legacy in a domain it shouldn't be
19:10
g3gg0
it is effective, yes. but there are colors you cannot reproduce with passive lighting
19:10
troy_s
The bottom line is that a camera is post spectral
19:10
g3gg0
yep
19:10
troy_s
Meaning that RGB is not reality.
19:10
g3gg0
yeah and every channel gets light that is not filtered ideal
19:10
troy_s
So in addition to our eyes being metameric, an RGB sensor is.
19:10
troy_s
Yes. Non-narrow band
19:11
Bertl
g3gg0: and that's good :)
19:11
troy_s
So a camera can never really reflect what it sees
19:11
troy_s
And will behave quite differently at different illuminants
19:11
troy_s
Blah blah
19:11
g3gg0
and you never really can corellate back of which color the thing was that is being imaged
19:12
troy_s
Bottom line is that A) 3D LUTs are vastly more accurate B) you need one for each varying of contexts (ISO, illuminant, etc.)
19:12
troy_s
(Hence look at the Sony or Arri LUT sets in OCIO)
19:12
troy_s
g3gg0: Nope. Hence post-spectral
19:12
troy_s
But we can get close in many instances
19:12
g3gg0
i tried to find the matrices various raw developing tools use.
19:12
troy_s
Close enough for post work
19:12
troy_s
Matrices suck
19:13
troy_s
Sensors just don't behave well enough.
19:13
g3gg0
i tried to reconstruct a LUT from that. i somewhen stopped because i couldnt explain what ive seen there :)
19:13
troy_s
Bertl hammered that into my head a while back
19:13
g3gg0
here it is https://www.youtube.com/watch?v=9Fz6V5aJSbk
19:13
g3gg0
as said, it was just an experiment to better understand what happens behind the scenes
19:13
troy_s
The problem is that some shapes may cover a decent volume of the gamut, but when you get to the edges, your DE goes through the roof
19:14
troy_s
Hence why a 3D LUT will almost always be vastly more accurate.
19:14
g3gg0
yeah absolutely
19:14
troy_s
(Stability of sensor notwithstanding)
19:14
troy_s
g3gg0: quit watching that crap
19:14
troy_s
Anytime anyone brings up Light room or ProPhotoRGB... Just worry.
19:15
g3gg0
i made that ;)
19:15
troy_s
You have found yourself too stuck in ICC land.
19:15
troy_s
The ICC tools can be leveraged to your whim, but you sadly have to know their graphic arts hacks
19:15
g3gg0
i dont have any other tools for developing CR2
19:16
g3gg0
(aside of RT, dcraw, DPP)
19:16
troy_s
Namely the damn D50 PCS absoluteness.
19:16
troy_s
g3gg0: We need to chat more. ;)
19:16
troy_s
g3gg0: You are obviously power nerd and can compile OCIO and OIIO?
19:17
troy_s
OCIO was developed to supplant the limitations of ICCs
19:17
g3gg0
troy_s: sure, just a lib with simple API
19:17
troy_s
In particular:
19:17
troy_s
A) Unlocking the forced chain of input-PCS-output
19:17
troy_s
B) Discarding the D50 rubbish
19:17
troy_s
C) Fine grained artistic control of transforms
19:17
g3gg0
unfortunately no direct DNG support. didnt check if the TIFF module is capable of writing DNG-alike TIFFS
19:17
PRN
left the channel
19:18
troy_s
D) Discarding the display referred-centric nature of ICCs
19:18
troy_s
g3gg0: I think you can manage.
19:18
troy_s
DPXs are pretty universal. And as I said, if someone added the tags for the TIFF side, quite sure Mr. Gritz would merge them for CinemaDNG.
19:19
troy_s
DPX and EXR still rule the roost (for good reason) in post land.
19:19
troy_s
g3gg0: But I think your transforms would greatly bump up a notch. You could end up with archival stored EXRs without breaking a sweat.
19:20
troy_s
(Scene linear too, which is a huge step toward post work)
19:21
troy_s
g3gg0: I forced OIIO to load a CinemaDNG, after all, it is a TIFF.
19:21
g3gg0
so one of your concerns is to dump the raw sensor data as early as possible into some industry standard image format that uses an universal colorspace?
19:22
g3gg0
(if i understood it right)
19:22
troy_s
There are no universal colorspaces. On the contrary.
19:22
g3gg0
well, lets then call it standardized ones :)
19:22
troy_s
But for imaging, it does help having the image in a useful entry format.
19:23
troy_s
g3gg0: So for example, one might want to process raw to DPX and archive the DPXs.
19:24
troy_s
g3gg0: DPX due to the inherent log “compression”, and EXRs due to their outright rejection of transfer curves and float depth that makes them the most ideal entry point for post work.
19:24
PRN
joined the channel
19:25
troy_s
g3gg0: Sense?
19:26
g3gg0
troy_s: what i dont get is - why would we ever care about any color space / LUT when writing data into an universal format like EXR. to my understanding all the data should match the scene as-shot. applying some LUT that looks the best on cinema screen or RGB monitors or CCTV is one of the last steps?
19:26
g3gg0
or do you talk about "recovering" the real tristimulus from the bayer pixels using LUTs
19:26
troy_s
Ultimately most will want to start native.
19:26
troy_s
To avoid crosstalk for keying or such.
19:27
troy_s
“match the scene” is really the end of a 3D LUT, but that isn't ideal either. Ideal for an entry to grading, but not for post always.
19:27
g3gg0
yes, matches my understanding
19:27
troy_s
Much of post isn't color critical, as long as there are assertions to not mangle the data.
19:28
troy_s
(So you still have to keep your eyes on it. Nightmare.)
19:28
Bertl
off for now ... bbl
19:28
Bertl
changed nick to: Bertl_oO
19:28
g3gg0
bye Bertl!
19:29
g3gg0
i just am frightened of baking color conversion matrices/LUTs into the data for archiving.
19:29
g3gg0
assume the LUT wasnt good enough
19:29
troy_s
g3gg0: You wouldn't. Always view transforms.
19:29
g3gg0
all your archived data is crap
19:29
troy_s
It is entirely plausible that an artist will need to see the work as it will appear to the grader's entry point.
19:30
troy_s
Hence you only tack that onto the view. (Most imaging apps have a distinct breakdown between the input / working slush / and view)
19:30
troy_s
Where working slush is always scene linear.
19:30
g3gg0
yeah thats a viewer story then, right?
19:30
troy_s
No, it's part of the imaging tool. Nuke uses OCIO.
19:31
troy_s
You set up your views and can toggle between them. So you chain transforms to have a reference to output (say reference to 709) then tack on your 3D LUT display correction
19:31
g3gg0
(ok i am not comfortable with all the words that professional PP guys are using :) )
19:31
troy_s
All the while your data is pure.
19:31
troy_s
Make sense?
19:31
g3gg0
yes this absolutely does
19:31
troy_s
It isn't professional; it is all needs.
19:32
g3gg0
hey, i shoot MP4 videos. this says it all? ;)
19:32
troy_s
If you fight through a short music video or indie, you learn pretty quick _why_ it makes sense.
19:32
troy_s
Even then, you can greatly improve your work by following that path.
19:32
troy_s
(I am a big believer in independents. Huge.)
19:33
g3gg0
i am neither a professional videographer nor a photographer. i am reverse engineer and a programmer with hobby photographing :)
19:33
troy_s
The only cost is disk storage, which is quite a lot cheaper than it ever has been.
19:33
troy_s
Sure. You are a perfect candidate to muck with it then.
19:33
troy_s
And probably enjoy doing it.
19:34
troy_s
Even breaking your MP4s down into stills will increase the flexibility you have.
19:34
g3gg0
ok back to one thing that bugs me...
19:34
troy_s
Everything from controlling the subsampling (a huge impact on your still image) to being able to composite say, fire, to getting to a correct film-like dissolve.
19:35
g3gg0
shooting color patches in D65 sunlight to determine the color conversion matrix liek e.g. dcraw does
19:35
g3gg0
to me this is only 50% of the story
19:35
troy_s
D50 to be more accurate.
19:35
troy_s
This is because they all rely on ICC tools.
19:35
troy_s
So matching the PCS is most ideal.
19:36
g3gg0
you shoot patches and build a matrix that should match all colors that are physically possible.
19:36
troy_s
The further you are from the PCS, the more inaccuracies are introduced via the CA to get it there.
19:36
troy_s
Hard to do with reflective charts. You need light boxes etc. But that said, a HCT is a good chart. IT8s are solid too.
19:37
g3gg0
yeah but the RGGB(raw) <- XYZ matrix you get from that is by far not correct
19:37
g3gg0
yeah
19:37
troy_s
Depends. It is actually pretty accurate.
19:37
troy_s
The metal basically takes a few things:
19:37
troy_s
A) The chart. Known XYZ positions in 2D space
19:38
troy_s
B) A data file that contains spectrophotometer readings of the actual chart print unique to each chart.
19:38
troy_s
C) The native tri-color data (RGB file)
19:39
g3gg0
especially with pink highlights a1ex found that a bunch of the common imagery tools produce RGB results that are far off the reality.
19:39
troy_s
You get two paths: matrix or 3D LUT. (Or tack on a shaper in there too)
19:39
troy_s
Matrix!
19:39
troy_s
You get that crap with matrices
19:39
troy_s
Less so with 3D LUTs
19:39
troy_s
But you also need to be acutely aware of your sensor and what it is doing
19:39
g3gg0
but then you really need lightboxes that cover a wide spectral range, right?
19:39
troy_s
For example, if you feed it raw unclipped RGB.
19:40
troy_s
No... Think of this mistake
19:40
troy_s
You feed the chart (most often underexposed)
19:40
troy_s
(You need to look at the text file outputs to see ideal exposure. It is often 1-2 stops hotter than most folks shoot charts.)
19:41
troy_s
But least mean squares to matrix is like drawing a line through points
19:41
troy_s
Even if 90% are damn close to the libe
19:41
troy_s
Line, the ends are probably way off.
19:41
troy_s
Hence pink or magenta or yellow
19:41
troy_s
Or someone bogs up the CA
19:41
troy_s
There are _many_ places to screw profiling up.
19:42
g3gg0
hehe absolutely
19:42
troy_s
If you would like, I can step through with Argyll and we can cut much of the crap out of the way and you can see the results
19:42
g3gg0
especially when having channels that are overexposed
19:42
danieel
still the biggest issue remains the proper lighting of the chart
19:42
troy_s
But they can be damn good, MUCH more representative than the default matrices.
19:43
troy_s
danieel: That is large. But not largest.
19:43
troy_s
Many many many places where a minor bumble in knowledge hoops the result.
19:43
troy_s
Overexposed is bad too, but so is under.
19:44
troy_s
Also, seeing as how a sensor will never see pure black or white, you have to add those points manually.
19:44
g3gg0
this is the reason why everyone hopes that making it community-driven will make it successful
19:44
danieel
that is easy to check, dont see it hard with exposure assist tools we have :)
19:44
troy_s
That will correct the glaring badness at the upper and low ends, preventing skewing off into grotesque color.
19:44
g3gg0
axiom needs at least one guy who takes some time and produces a perfect* color profile :)
19:44
troy_s
There are a lot of damn sharp minds out there. Collective efforts are tough though.
19:45
PRN
left the channel
19:45
g3gg0
cant we measure the spectral response for every single bayer filter R, G1, G2, B and built a LUT from that?
19:46
danieel
they are measured
19:46
danieel
look at the QE charts from the sensor makers
19:46
troy_s
Not narrow band!
19:46
troy_s
Can not work.
19:46
troy_s
RGB != spectral.
19:46
troy_s
So two problems.
19:46
g3gg0
nah i really think about following the spectral curve
19:47
troy_s
And, the sensors misbehave differently with different factors.
19:47
g3gg0
they do?
19:47
troy_s
So ISO? Different LUT. Color temp? Different LUT.
19:47
troy_s
Etc.
19:47
troy_s
But the non-narrow band is the big killer there.
19:48
g3gg0
ISO: right. color temp? no, that would suprise me. we talk about raw video :)
19:48
troy_s
Needless to say, decent profiles can be had if the sensor can be tamed.
19:48
g3gg0
but sensor temperature will cause trouble
19:48
troy_s
Color temp of illuminant. ;)
19:48
troy_s
And temperature yes.
19:48
troy_s
And a bunch of other crap.
19:48
danieel
g3gg0: color temp is another curve, which defines the input light's spectrum...
19:49
g3gg0
nah maybe i expressed myself wrong.
19:49
troy_s
The taming of the sensor is hardest.
19:49
danieel
might not be just one bump on the chart
19:49
troy_s
I cannot do anything about that.
19:49
g3gg0
danieel: did all of that already by hand, so basics are known
19:49
troy_s
That is hardware nerdery.
19:49
troy_s
And mixed illuminants
19:50
troy_s
I was shocked at how awful the sensor behaved
19:50
troy_s
Really shocked
19:50
troy_s
I was always used to the "raw" data I saw off of a DSLR
19:50
troy_s
Little did I know how massaged that was
19:50
danieel
i think it is just the issue of the cmosis sensor
19:50
g3gg0
troy_s: i really thought about measuring every single CFA (wideband) filter for their spectral response. e.g. like those http://www.astrosurf.com/buil/350d/350d.htm (but he made the mistake and didnt use RAW but PP-ed RGB)
19:50
troy_s
Bertl and danieel had plenty of insight on that front.
19:51
g3gg0
or this one: http://www.astrosurf.com/buil/eos40d2/filter.htm
19:51
troy_s
g3gg0: Seems like a fool's errand to me, but I wouldn't try to insist someone not try.
19:52
troy_s
The bottom line is that all glass / plastic adds crosstalk
19:52
troy_s
To already non-spectral gathering
19:52
troy_s
So the battle is already fruitless
19:52
danieel
if the vienna guys can setup a proper lighting, i can bring my head and the hct, to make proper data to start with
19:52
troy_s
Varying levels of light will mix differently at different zones
19:52
danieel
around 28-29 oct, will be at pioneers.io
19:53
troy_s
Hell, people loved shooting film _because_ of the unique crosstalk
19:53
troy_s
Now we evolve away from that, toward gathering of scene data, and attempt to leave that to the creative ending point to control.
19:54
troy_s
danieel: Do you have the text file with the HCT?
19:54
danieel
yes, matched with the batch of the print
19:54
troy_s
If you get even lighting, you should get a pretty decent set of profiles. I would do ISO and other variables too so you can get a few.
19:54
troy_s
Yep.
19:54
troy_s
Solid charts.
19:55
troy_s
I wonder if there are high end light boxes that tag extremities of the spectral locus.
19:56
g3gg0
what i (naively) thought is, getting the spectral response for every CFA filter R, G1, G2 and B to make up a matrix. this matrix is the coordinate system for the colors being measured. e.g. if R/G/G/B is 0/0/0/1 then the real input color can be in range of the spectral response of the blue filter. (e.g. this plot: http://www.astrosurf.com/buil/eos40d2/graph5.png ). i know that recovering a color in XYZ space from the CFA output is as complex a
19:57
g3gg0
this would be the most (mathematically) correct method to get the "real" color of the thing being shot
19:58
g3gg0
processing an image would take 1k times as long, depending on the accuracy of the spectral response curve complexity
19:58
g3gg0
but i bet astroguys would kiss us for that ;)
19:59
troy_s
Still won't work
19:59
troy_s
Because you also ignore the objecy
19:59
g3gg0
at the moment matrix-tools work as if the CFA would be narrowband
19:59
troy_s
Object, which will also behave differently
19:59
g3gg0
so all colorspaces do
19:59
troy_s
Read the Argyll list on watercolors recently
19:59
troy_s
There is some deadly complex stuffs that happen as anyone that does imaging knows too.
20:00
troy_s
For example, were you aware that RGB rendering models will result in different results for indirect lighting?
20:00
troy_s
As in your choice of primaries matter.
20:00
g3gg0
what my proposed method returns is not the exact color, but the color probability. there are no real primaries anymore
20:01
g3gg0
primaries = assuming narrowband
20:01
troy_s
And on your point of matrices, hence why I am a 3D LUT believer. They model crosstalk vastly more accurately.
20:01
troy_s
But they aren't narrow band
20:01
g3gg0
exactly!
20:01
troy_s
The humps kill you
20:01
g3gg0
thats why so many odd things happen with colorspace conversion
20:01
troy_s
And kill you on about sixteen fronts
20:02
troy_s
Hell yes. But again, a good chart (HCT / IT8) captured
20:02
troy_s
Can give you pretty damn good results if processed with care.
20:02
g3gg0
e.g. check the images at http://magiclantern.fm/forum/index.php?topic=5197
20:02
g3gg0
especially the blue LED
20:03
g3gg0
using primaries and matrices only led the image developing tool to treating the blue LED as pink
20:03
g3gg0
when color reconstruction jumps in, everything is a mess
20:05
g3gg0
(iirc during the tests a1ex revealed that the matrices used in dcraw have some conceptual errors that lead to odd colors even when channels are not blown out)
20:07
g3gg0
anyway. was a nice chat with you. thanks for all the information
20:07
g3gg0
its time to get some rest :)
20:10
troy_s
g3gg0: I think we can do better
20:10
troy_s
g3gg0: Maybe you, me, and Alex can do a chat soon
20:10
troy_s
I am reasonably certain we can do better.
20:11
troy_s
g3gg0: great chatting with you too. It is lovely that there is a little channel where color nerds can hang
20:11
troy_s
(Was excellent at SIGGRAPH too, as I got to meet and chat with all of the gods like Mr. Selan, Mr. Gritz, and a crap load of other bright heads.)
20:18
sebix
left the channel
20:20
intracube
alexML: I just looked at the UFRAW thread g3gg0 posted
20:20
intracube
awesome work!
20:31
troy_s
I have to wonder what ACR is doing.
20:31
troy_s
Could be a cheat in there.
22:48
se6astian
good night
22:48
se6astian
changed nick to: se6astian|away
22:48
g3gg0
left the channel
23:45
Bertl_oO
changed nick to: Bertl
23:45
Bertl
back now ...
23:56
wescotte
joined the channel