Thursday, July 30, 2015

Re: [Avid-L2] Best Method for upside down Arri Alexa camera media?

 

I personally haven't seen the footage but I was told that QT played it in the proper orientation.  Does that make sense?  I was told that when they tried to use QT or perhaps MPEG streamclip they lost the time code.  I will have to ask them a few more questions to see exactly what they did.  Does QT Pro 7 understand the Arri meta data that relates to camera orientation?  Given I'm told that it played properly that's what I'm thinking.  My experience with QT Pro7 is that a "Save As" will maintain the time code of the original clip.  If QT does the flipping of the image does that require and "Export" vs. "Save As"?

In order for QT to flip the image and resave is there something that has to be set in the movie properties for the video track or is this all automatic?  I will try and get more info on the files they have and exactly what they have tried so far.

Is the camera orientation meta data based on a sensor in the camera or is it something the operator has to set?  I don't know why they had to mount the camera upside down.  Perhaps there is a rigging reason although I haven't seen this happen on other shoots with the same cameras so I'm curious what was different this time.



---In Avid-L2@yahoogroups.com, <bogdan_grigorescu@...> wrote :

if they shot ProRes, you can non-destructively flip it in QT , then re-transcode to DNxHD

BG



From: "John Moore bigfish@... [Avid-L2]" <Avid-L2@yahoogroups.com>
To: Avid L2 <avid-l2@yahoogroups.com>
Sent: Thursday, July 30, 2015 9:25 PM
Subject: [Avid-L2] Best Method for upside down Arri Alexa camera media?

 
Working on a multicamera show where the Jib camera was mounted upside down.  I believe the camera is an Arri Alexa or maybe Amira.  Apparently the media contains meta data that deals with the camera orientation and playing the clips in QT or MPEG Streamclip will automatically flip the shot to proper orientation.  I'm not sure if the DIT did the transcodes for offline but the media they have for Avid isn't properly oriented so the one jib shot is upside down in the multigroup. 

I've tested and I can use Resolve to flip H and V to make the shot proper.  My question is I'm pretty sure the camera original media is ProResHQ 422 and I want to know if I had Resolve just bake out to ProResHQ 422 media files would this be more of a rewrapping with proper orientation of the media or would it be a transcode?  Also as I'm fairly new to Avid 8.3.1 is there a provision in the new source settings like Frame Flex that would allow for the H and V flip to occur on ama'd clips from the Alexa thereby bypassing the need for Resolve?

I know in the past Oliver and others have pointed out that we could use the ProRes media natively in Avid but in the past we have been running 5.5.5 or earlier and I don't think that was possible.  Now we've upgraded to Ver. 6.5.4.6 so perhaps that is a more viable approach.  I've been a fan of baking in the standard Arri to 709 LUT to my DNX 175 online clips and working that way as I don't need to all the extra controls and I'm still in a pre LUT version of Avid.  Would consolidating the ProRes Camera master media to rewrap it into a more robust avid .mxf file work as smoothly as my traditional DNX 175 approach?
 
John Moore
Barking Trout Productions
Studio City, CA
bigfish@...


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