Just hit this server side, not sure how...
*** Error in `/bin/python': double free or corruption (!prev): 0x00007f1f41c34880 *** ======= Backtrace: ========= /lib64/libc.so.6[0x3fe207cef8] /usr/lib64/python2.7/site-packages/xpra/codecs/csc_swscale/colorspace_converter.so(free_csc_image+0xc)[0x7f1f5cdc5e3c] /usr/lib64/python2.7/site-packages/xpra/codecs/csc_swscale/colorspace_converter.so(+0x53dc)[0x7f1f5cdbd3dc] /lib64/libpython2.7.so.1.0(PyObject_Call+0x43)[0x3fe1c49dd3] /usr/lib64/python2.7/site-packages/xpra/codecs/csc_swscale/colorspace_converter.so(+0x7d05)[0x7f1f5cdbfd05]
Not seen it since, though vpx doesn't really get much testing...
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/358