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#apertus IRC Channel Logs

2014/05/08

Timezone: UTC


01:07
Topic
apertus° - open source cinema | www.apertus.org | Currently Hot: Axiom Alpha Development http://axiom.apertus.org/ | IRC Logs available at: http://irc.apertus.org
01:07
se6astian
has set the topic
01:27
jucar
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05:12
gcolburn
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gcolburn
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05:25
Bertl
off to bed now ... have a good one everyone!
08:13
se6astian
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08:15
se6astian
good morning
12:34
Bertl
morning folks!
13:53
Bertl
off for now ... bbl
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18:05
Bertl
back now ...
18:27
intracube
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20:08
intracube
hello :)
20:08
Bertl
hey :)
20:08
intracube
wow, that was quick :P
20:08
Bertl
I'm a bot.
20:08
intracube
heh
20:09
Bertl
do you want to take a touring test?
20:09
Bertl
-o
20:09
intracube
I think *I'd* fail a touring test right now ;)
20:10
intracube
*Turing
20:10
intracube
I've just been catching up on your project and the moving image samples post - awesome results!
20:11
Bertl
that's glad you like them
20:11
intracube
in the PLR demo vid, the moire patterns on the curtains disappear https://www.youtube.com/watch?v=OUaHXvX-BIc
20:12
Bertl
I think they just get too small to be visible
20:13
intracube
is this just the low contrast + YT compression
20:13
intracube
ah
20:13
Bertl
there is a lot of stuff going on between the actual image and what you see
20:14
Bertl
i.e. the HDMI encoder, the recording, the compression/codec
20:14
intracube
Bertl: right
20:17
intracube
I wonder if the PLR footage is converted back to linear, the aliasing would reappear
20:19
Bertl
probably but not that much
20:19
intracube
Bertl: is there a HQ downloadable video of this: https://www.youtube.com/watch?v=zmdEW5MxGN0
20:19
Bertl
aliasing is the result of diffraction and non uniform recording
20:19
intracube
or maybe some still caps?
20:20
Bertl
maybe, you have to check with Sebastian when he is back (or via email)
20:20
intracube
yup, ok
20:21
intracube
Bertl: also the optical lowpass filter
20:22
intracube
does the alpha sensor have one as standard?
20:22
Bertl
not that I would know
20:23
Bertl
i.e. there might be some 'magic' incorporated into the micro lens system, but I doubt it
20:24
intracube
ah, no optical LPF would likely be the cause of the moire
20:24
intracube
or at least a significant part of it
20:26
Bertl
yes, aliasing is always a problem with cameras
20:33
Bertl
so, what's your opinion on beta? if I may ask?
20:45
Bertl
none? :)
20:46
intracube
Bertl: the feature list is pretty ambitious
20:46
Bertl
okay, so, will you buy one?
20:46
intracube
a couple of the features; remote control from smartphone/tablets
20:47
intracube
and accelerometer features seem rather niche
20:47
intracube
Bertl: I'm not sure my bank balance would go that far :/
20:47
intracube
but I wouldn't rule it out
20:48
Bertl
okay, so it looks nice, but it isn't something you would spend your money on
20:49
Bertl
did you spend money on cameras before? (just curious, not judging or so, and just let me know if you don't want to answer)
20:50
intracube
I've only just read up about the beta! still a fair amount of unknowns :)
20:50
intracube
the issue with this end of the market is the camera is only one small part of the total cost
20:50
Bertl
so you want to know more about it then? if so, just ask, we'll try to answer
20:52
intracube
there would be no onboard consumer level (AVCHD) recording?
20:53
intracube
so an HDMI recorder would be necessary. and I've just read up about the compatibility issues with some of these devices :)
20:53
Bertl
correct, the main reason for that is that we do not have the bandwidth or interfaces (atm) for this on the microzed
20:54
Bertl
i.e. you can of course record to SD card, but you know that the speed is very limited even for high end cards
20:54
Bertl
so no chance to record raw data, even for 1080p on that
20:55
Bertl
there will be a flexible I/O module, and we will start with HDMI on that one, but it might be an option for some kind of SATA or SSD interface lateron, although I doubt that we will be able to record full raw over that
20:56
Bertl
the compatibility issues are something which can be solved via software
20:57
Bertl
i.e. of course, it's not easy to figure out what a proprietary recorder from big company XY actually means if it says 'no signal' :)
20:57
intracube
in many cases HDMI devices recording direct to prores is much more practical
20:58
intracube
recording uncompressed to HDD would require massive amounts of storage/processing
20:58
intracube
(obviously) :)
20:58
intracube
Bertl: any idea how long you plan to make the beta available for?
20:58
Bertl
@prores, I'm pretty sure that there is no open/free encoder available
20:59
intracube
I thought ffmbc did it?
20:59
Bertl
I don't think that we will explicitely stop the 'beta' at any point ... would be hard to stop open hardware anyway
21:00
intracube
tho there may well be prores licensing issues that have been ignored there...
21:00
Bertl
not to speak of potential performance issues
21:00
Bertl
but the good news is, you can do that on your axiom beta :)
21:02
intracube
and if I was voting for a particular sensor, it'd be the cmv12000
21:02
Bertl
any particular reason why?
21:03
intracube
the size (depth of field, greater compatibility with SLR lenses) and frame rate (even if 300fps is only achieved after the beta) is more than worth the price increase
21:05
Bertl
so you would feel comfortable paying about 1500 bucks for the sensor alone?
21:07
intracube
apart from lenses, it's one of the most important components
21:08
intracube
£880 for the cmv12000 vs £320 for the cmv8000 isn't that much
21:09
intracube
you'd pay the difference for a decent lens
21:09
Bertl
and the kodak?
21:09
Bertl
I mean, except for the frame rate, it seems to be almost compareable to the cmv12k
21:09
Bertl
at least from the technical details available
21:10
Bertl
for roughly half the price
21:10
intracube
I haven't seen the spec for the kodak
21:10
intracube
oh, that's the KAC12040
21:11
Bertl
yep
21:12
intracube
4/3 is that much more of a crop factor over s35 (DX format)
21:12
intracube
would need to do some tests and get a feel for how much field of view is lost
21:13
intracube
are there any low light sensitivity comparisons for these sensors?
21:15
Bertl
image area: 22.5x16.9 vs 18.8x14.1
21:16
intracube
http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Sensor_sizes_overlaid.svg/600px-Sensor_sizes_overlaid.svg.png
21:19
intracube
a fairly significant crop over aps-c/DX/s35
21:21
Bertl
okay, so that's important for you and worth the money
21:23
intracube
maybe not by itself, but with the possibility of 300fps@10bit for the 12000
21:23
intracube
but then then any recording method for 300fps sounds... expensive :)
21:24
Bertl
150 FPS with the current V1, in theory 300FPS with the v2 chip
21:25
intracube
would this be dumped raw to HDD then debayered later?
21:26
Bertl
I don't think it would help to debayer before writing the data unless compression needs that, so yes, raw to HDD and debayer later
21:29
intracube
but does that mean the whole sensor 4096 x 3072 @ 10bpp (padded to 16bit?) x 300fps
21:33
intracube
anyways, I need food
21:33
intracube
thanks for the chat Bertl :)
21:36
Bertl
yes, typically raw will record the full pixel size, and often unpacked, althouth 10/16 would be extreme
21:37
Bertl
so packing the data into blocks of 80 bits would be preferable
21:37
intracube
I guess maybe the data could be truncated to 8bit at hardware level before dumping to HDD?
21:39
intracube
and possibly the central 2k area (windowed mode) could be chosen to cut down data requirements
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