title: Non-monotonous DTS in output stream previous current changing to This may result in incorrect timestamps in the output file
body: <p>I am having a file.txt with rather close snippets</p>
  <pre><code>file 'input.mp4'
  inpoint 1.5402465510368346
  outpoint 2.722609395980835
  file 'input.mp4'
  inpoint 3.192511146068573
  outpoint 7.074568028450012
  file 'input.mp4'
  inpoint 7.851800565719604
  outpoint 9.023683423995971
  file 'input.mp4'
  inpoint 10.054571752548219
  outpoint 12.008032734394073
  file 'input.mp4'
  inpoint 18.70977670431137
  outpoint 21.20993923664093
  file 'input.mp4'
  inpoint 24.51183382153511
  outpoint 26.465287650823594
  ...
  </code></pre>
  <p>I concat them with</p>
  <pre><code>ffmpeg -safe 0 -f concat -i file.txt out.mp4
  </code></pre>
  <p>and I tried</p>
  <pre><code>ffmpeg -use_wallclock_as_timestamps 1 -safe 0 -f concat -i file.txt out.mp4
  </code></pre>
  <p>Yet I get</p>
  <pre><code>[mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 2069, current: 2067; changing to 2070. This may result in incorrect timestamps in the output file.
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 2070, current: 2067; changing to 2071. This may result in incorrect timestamps in the output file.
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 2071, current: 2067; changing to 2072. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 2758, current: 2756; changing to 2759. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
      Last message repeated 5 times
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7581, current: 7579; changing to 7582. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7582, current: 7579; changing to 7583. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7583, current: 7579; changing to 7584. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7584, current: 7579; changing to 7585. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7585, current: 7579; changing to 7586. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7586, current: 7579; changing to 7587. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7587, current: 7579; changing to 7588. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7588, current: 7579; changing to 7589. This may result in incorrect timestamps in the output file.
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7589, current: 7579; changing to 7590. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  [mp4 @ 00000178c514cc00] Non-monotonous DTS in output stream 0:1; previous: 7590, current: 7579; changing to 7591. This may result in incorrect timestamps in the output file.
  [aac @ 00000178c50f8a80] Queue input is backward in time
  </code></pre>
  <p>And the final file is cut at wrong places.</p>
  <p>How to make the file.txt work?</p>