alexa mini Capture rez issue

Wed Mar 14, 2018 6:05 pm

I have some alexa mini footage that is 2:1 scope

In my baselight it says resolution 2578x2160 (crop rez @2560x2145) but full sensor at 3424x2202

my SDK imported it at 2578x2160
but client wants it at 2592x2160

looking at the arri documents , I see SXT can record at this rez in "6:5 mode".
but my footage is full OG 3.4k

could a mistake been made at camera settings to cause this?
Are there more resolution options than what the spec sheets say?

thanks for any help,
TomT
NYC
celboy
 
Posts: 10
Joined: Wed May 18, 2016 10:41 pm

Re: alexa mini Capture rez issue

Thu Mar 15, 2018 4:30 pm

Dear Tom,

everything is all right.

ALEXA Mini has three MXF/ARRIRAW modes (16:9 HD Ana. (OG 3.4K), 2.39:1 2K Ana. (OG 3.4K), 4:3 2.8K (OG 3.4K) in which the camera captures an open Gate image, but tells the SDK via metadata "use only tthat area: x-by-y".

For Alexa Mini, the 2.39:1 mode it is recording 3440x2202, but the SDK will output: 2560x2145

For ALEXA SXT, in 6:5 mode you record 2592x2160, but the SDK will output: 2578x2160.
We record more pixels for more convenient data alocation within the files, but do not allow 2592x2160 to be used since it is 1,2:1 and not 1,1935:1 - which times twi will be 2.39:1.

See our 'prayer rug' for more: http://www.arri.com/?eID=registration&file_uid=18771

Cheers,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
Posts: 291
Joined: Wed Aug 13, 2014 3:15 pm
Location: Munich, Germany

Re: alexa mini Capture rez issue

Fri Mar 16, 2018 4:37 am

thank you Jan,

In my scenario, the clients specifically requested this rez from production but I guess since they didn't have that exact camera--they were stuck with mini's specs. In any case, after working in my default sdk mode, & doing the job--later, I was able to access the full OG and give them what they requested with minimal xtra work.

Apparently they based this spec on what Autodesk flame was giving them--in "native full" mode they see 2592x2160.
And in regular "native" mode-it shows 2578x2160.
I would think flame would see the camera metadata & allow access to the chart (i.e. your prayer rug) rez's for each camera.But I guess not. I ddi leave a post on their forum for clarification too.

thanks again
TomT
celboy
 
Posts: 10
Joined: Wed May 18, 2016 10:41 pm

Re: alexa mini Capture rez issue

Fri Mar 16, 2018 1:29 pm

Hey Tom,

please keep us posted!

Best,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
Posts: 291
Joined: Wed Aug 13, 2014 3:15 pm
Location: Munich, Germany

Re: alexa mini Capture rez issue

Thu Mar 22, 2018 3:36 am

Hi Jan,

Autodesk Response is---
Native is the resolution as set in camera and native-full is the recorded sensor resolution in a non Open Gate recording. You get some extra pixels in case you need to perform operations.

Thanks for your help in all this.
TomT
celboy
 
Posts: 10
Joined: Wed May 18, 2016 10:41 pm

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