AWS Thinkbox Discussion Forums

checking for bad frames

Hi, we render on a render farm using Deadline.



We mainly use Maya and MentalRay for Maya.



When things get busy, we’ll start having random frames which do not render completely or correctly.



I’m sure other people out there have experienced this too.



Please, can we start a discussion with an aim to solve for the best way of handling this situation?



In a perfect world, the farm software would be able to find these bad frames and re-render them.



I worked at a place where they had a Perl script which somehow tested the frames. It used several methods for testing the image sequences. I don’t know all the ways it did this, but I recall that the main testing method was to simply comparing them in a sequence and checking to see if a file size suddenly and dramatically changed.



I’m not wed to this method. I’d love to hear what others out there do or recommend.



ps I’m not a scripter.

Maybe with a post job script.

Problem though is, how to read out all the layers and outputs from the Maya MB/MA file?


Not sure I see where this is a problem. The (Deadline) renders should know their output directory; and they should know when they're completed rendering.

The work flow goes like this...

Render completes > script is launched and performs a check of the finished sequence of frames > script outputs the suspect frames to a list > and perhaps Deadline relaunches the renders for just those frames.

The trick here is to solve for the best way to determine if the frames are bad. I've yet to find a way which will catch the bad frames in any sort of definitive way due to the seeming nature of 3D renders.

The place I worked before had a script which listed all the frames in a sequence in order by frame number, then compared their file size and if a frame was smaller than a surrounding frame by a percentage, it would tag the frame by placing 5 astrixs next to it in the printout the script output to a text file. It was 99.9% accurate.

People who render in tga file format will find this to work very well for them since all tgas images from the same render will be the same size. Bad frames will be maybe 50k when the good image files are something around a meg.

But here and now, we don't (and won't) render in tga -- even if it does provide this handy functionality.

Still, rendering in iffs or tifs the method mentioned above works fairly well; though it is a bit more tricky.

I believe there is a better way....

~L



Lee Mylks
Computer Animator/Modeler/Lighter/Particle Effects and Dynamics Simulator
lee@leemylks.com





To: From: Frantic_Deadline.listmanager@support.franticfilms.comSubject: checking for bad framesDate: Mon, 3 Dec 2007 10:12:18 -0500From: "sven neve" (sven@houseofsecrets.nl)
Maybe with a post job script.Problem though is, how to read out all the layers and outputs from the Maya MB/MA file?

To reply:Frantic_Deadline.4504@support.franticfilms.comTo start a new topic:Frantic_Deadline@support.franticfilms.comTo view discussion: http://support.franticfilms.com/WB/?boardID=Frantic&action=9&read=1030&fid=7To (un)subscribe:Frantic_Deadline.list-request@support.franticfilms.com

Well, if it is possible to disable the compression on those formats it would be the same as your tga workflow (not sure Maya allows for something like that though)



Another option would be to tie the error checking to a script that parses the output of XnView’s nconvert.exe with the -info flag, this only reports image info, and when the image is corrupt it will throw an error.

framefixer will auto-tag missing and 0-byte frames, and i see deadline has support for it now. we don’t own framefixer, but maybe it could be set to run post-render and regenerate broken frames?



http://www.framefixer.com/



i know there’s a collection of tools for frame comparison, designed to measure if 2 frames look identical to the human eye. not sure if you can set a tolerance threshold (ie handle animation), but food for thought.



http://sourceforge.net/projects/pdiff

Privacy | Site terms | Cookie preferences