user6685: I'd like to batch convert some log footage as well as transform each clip into rec709 colorspace. Is there any way to apply a custom lut to the footage? If so, what's the correct way to do that?

user19140: You may want to use FFMPEG's lut3d filter. It requires you to provide a look-up table (a *.cube file). For example, if you have an ARRI camera you can generate these files using ARRI Color Tool or simply download a package with them from the linked page.
Once you have the files, use FFMPEG like this:

ffmpeg -i "Input.mov" -vf lut3d="ARRIP3D65PQ108-33.cube" -s 1920x1080
  -c:v dnxhd -pix_fmt yuv422p -b:v 120M DNxHD_for_Editing.mxf

The important part here is the use of lut3d filter:

-vf lut3d="ARRIP3D65PQ108-33.cube"

where ARRIP3D65PQ108-33.cube is the LUT file to use with the filter.

6685: <p>I'd like to batch convert some <em>log footage</em> as well as transform each clip into <em>rec709</em> colorspace. Is there any way to apply a <em>custom lut</em> to the footage? If so, what's the correct way to do that?</p>
 19140: <p>You may want to use FFMPEG's <a href="https://ffmpeg.org/ffmpeg-filters.html#lut3d-1" rel="noreferrer">lut3d</a> filter. It requires you to provide a look-up table (a *.cube file). For example, if you have an ARRI camera you can generate these files using <a href="http://www.arri.com/camera/amira/downloads/" rel="noreferrer">ARRI Color Tool</a> or simply download a package with them from the linked page.</p>

<p>Once you have the files, use FFMPEG like this:</p>

<blockquote>
  <p>ffmpeg -i "Input.mov" -vf lut3d="ARRIP3D65PQ108-33.cube" -s 1920x1080
  -c:v dnxhd -pix_fmt yuv422p -b:v 120M DNxHD_for_Editing.mxf</p>
</blockquote>

<p>The important part here is the use of <strong>lut3d</strong> filter:</p>

<blockquote>
  <p>-vf lut3d="ARRIP3D65PQ108-33.cube"</p>
</blockquote>

<p>where ARRIP3D65PQ108-33.cube is the LUT file to use with the filter.</p>
