mestimate not producing metadata

[Alan Piszcz]

The mestimate values for each frame should be written to test.txt.
The output file test.txt contains pts information, no mestimate values.

frame:0 pts:0 pts_time:0
timecode=00:00:00:00
frame:11 pts:33000 pts_time:0.366667
timecode=00:00:00:12
frame:23 pts:69000 pts_time:0.766667
timecode=00:00:00:24
frame:35 pts:105000 pts_time:1.16667
timecode=00:00:01:06
frame:47 pts:141000 pts_time:1.56667
timecode=00:00:01:18
frame:59 pts:177000 pts_time:1.96667
timecode=00:00:02:00
frame:71 pts:213000 pts_time:2.36667
timecode=00:00:02:12
frame:83 pts:249000 pts_time:2.76667
timecode=00:00:02:24
frame:95 pts:285000 pts_time:3.16667
timecode=00:00:03:06
frame:107 pts:321000 pts_time:3.56667
timecode=00:00:03:18
frame:119 pts:357000 pts_time:3.96667
timecode=00:00:04:00
frame:131 pts:393000 pts_time:4.36667
timecode=00:00:04:12
frame:143 pts:429000 pts_time:4.76667
timecode=00:00:04:24
frame:155 pts:465000 pts_time:5.16667
timecode=00:00:05:06
frame:167 pts:501000 pts_time:5.56667
timecode=00:00:05:18
frame:179 pts:537000 pts_time:5.96667
timecode=00:00:06:00
frame:191 pts:573000 pts_time:6.36667
timecode=00:00:06:12
frame:203 pts:609000 pts_time:6.76667
timecode=00:00:06:24
frame:215 pts:645000 pts_time:7.16667
timecode=00:00:07:06
frame:227 pts:681000 pts_time:7.56667
timecode=00:00:07:18
frame:239 pts:717000 pts_time:7.96667
timecode=00:00:08:00
frame:251 pts:753000 pts_time:8.36667
timecode=00:00:08:12
frame:263 pts:789000 pts_time:8.76667
timecode=00:00:08:24
frame:275 pts:825000 pts_time:9.16667
timecode=00:00:09:06
frame:287 pts:861000 pts_time:9.56667
timecode=00:00:09:18

The same test with 'signalstats' in place of 'mestimate' produces the output in the documentation.

ffmpeg -f lavfi -i testsrc=duration=10:size=1280x720:rate=30 test.mp4

ffmpeg -y -i test.mp4 -filter_complex "mestimate,metadata=printfile=test.txt" test_out.mp4

ffmpeg -y -i test.mp4 -filter_complex "mestimate,metadata=print:key=lavfi.mestimate:file=test.txt" test_out.mp4