Before the patch:
- stored values were rounded to upper 16 multiple also for formats not 
using macroblocks (should be st->codecpar->width and 
st->codecpar->height when not MPEG formats; note that I found no other 
muxer doing the rounding for AVC, only for MPEG-2 Video, but I find no 
reason in specs for doing the difference so I kept the rounding for AVC)
- sampled and displayed widths were stored width (should be 
st->codecpar->width like it is already done for height, with the 
DV50/100 exception)

Could be tested with e.g.
- fixed stored width (1912 instead of 1920) and height (1080 instead of 
1088) not multiple of 16 :
ffmpeg -f lavfi -i testsrc=duration=1:size=1912x1080 -c:v jpeg2000 
test_prores.mxf
- fixed sampled/displayed width (1912 instead of 1920):
ffmpeg -f lavfi -i testsrc=duration=1:size=1912x1080 -c:v mpeg2video 
test_mpeg2video.mxf