Having a video preview (at least of the first sample chunk) would improve usability of the progressive rendering, as only a list of linear EXR files isn't all that useful.
This would require correct conversion from the linear EXR files to the desired output colour space. Options to investigate are:
- Use OpenColorIO's ocioconvert tool to convert the files, then feed to FFmpeg.
- Use the Blender sequence editor to output PNG files in the correct colour space to feed to FFmpeg.
- Open the job's blend file, duplicate the scene with 'copy settings only', fill the VSE with the EXR sequence, then render to PNG.
- Create a new blend file, copy certain colour/OCIO-related settings (using BAT maybe?) from the original blend file, then fill the VSE with the EXR sequence and render to PNG.
- Bake a LUT file from Blender's colour settings, and give that to FFmpeg to let it do the colour conversion.