I recently read Karl's post " Netflix has published a large sample of professionally produced 4k HDR video in Material Exchange Format container under a Creative Commons license.
“Meridian” is 4K HDR video shot with 60 frames per second with a peak brightness level of 4000 nits and Dolby Atmos audio. In other words: It pushes the boundaries on all specs fronts, and includes a number of visuals that can trip up encoders.
You can download the MXF and some auxillary files at https://media.xiph.org/video/derf/meridian/MERIDIAN_SHR_C_EN-XX_US-NR_51_LTRT_UHD_20160909_OV/
Did a forum search and found post by fish "Editing or creating MXF or DNxHD files (Read 341 times)...FFmpeg, an open source project added support for muxing and demuxing of MXF and MXF D-10 in FFmpeg 0.5, released in March 2009."
Does the last Windows version of Avidemux contain everything needed to Edit MXF?