MLVApp Batch Process MLV Files on The Commandline

[jedypod]

First: Thank you so much for the great application for processing and transcoding MLV files. MLVApp is by far the best solution for this right now, and I have a huge appreciation for all the efforts you have done to create it!

So I am working on hacking together an image processing pipeline to convert MLV raw files into scene-linear ACES EXR files for vfx. I have a few tools for Debayering and dailies movie generation based on Rawtherapee, OpenImageIO, and OpenColorIO ( see debayer and generate-dailies ).

The more manual part of this process is converting from MLV to cDNG for processing. For this part I use MLVApp.

An ideal workflow would be to use MLVApp for exporting lower quality dailies movies using the built-in ffmpeg output. After editing in Resolve or Premiere, exporting an XML, and then usuing that edit information to batch export (with in / out + handles) for each MLV file used.

For this to really be possible I believe I would need a scriptable commandline interface to the functionality of MLVApp. Is this even a remote possibility with MLVApp's architecture?

Maybe programmatically creating MLVApp receipt files or project files?

Advice would be appreciated!

Thank you!

[masc4ii]

Very interesting to read what you wrote. Thanks.

At least from Resolve and FCPX you could export FCPXML files which can be imported by MLVApp. MLVApp trys to open all MLV files, which were used with same name as proxy's in the project. For me that works very well and I use it very often - for all my projects. You just have the problem: if you have a long MLV and want to use just some frames, you render the entire clip.

Until now I don't use in and out handles because FCPX does not work when relinking shorter files. Another problem would be that you run into naming problems when there are multiple in's and out's for one MLV - this doesn't work at all for now.

It is not possible to script MLVApp, there is no interface for that. And for all those hundreds of functions I am not sure if there will be a script interface ever. But maybe the project "Switch" helps you: this is a commandline tool to process MLV via ffmpeg.

Creating MASXML files could be your solution. Just save a session and look into the file. I think it is not hard to understand how it is build. A receipt file is 99% identical but for just one "undefined" clip.

[ilia3101]

WHat is a librbary to save these EXR images, it could be done really easy with ACES branch if a nice easy library for that exists

[jedypod]

Thanks for the suggestions and the information!
After lookingat the MASXML file format I do think that would be the easiest way to go to solve my problem.

It would be super interesting to have the writing of exr files built in to MLVApp, especially if you are able to support ACES output.

The best bet in terms of libraries to support this would probably be OpenImageIO - It's massive but it's the most reliable library for manipulating floating point image formats I'm aware of.

Hope that helps, and looking forward to seeing this! I am going to keep an eye on the ACES branch development...