[FFmpeg-user] video slows down in the middle

[Henry Lau]

Hello,

I tried to convert a Webm file to MP4. The output MP4 file is fine, plays
normally at the start.
But for some reason, in the middle it goes into "slow-motion".
It then speeds back up to normal speed at the end.

The screenshot below is when I view the output MP4 in QuickTime. At the
bottom, you can see a "frame bar" (not sure what it's officially called).
The middle part is the part where it slows down.

[image: Inline image 1]

Command I used to convert:
./ffmpeg -i inputWebm out.mp4

The input video is here
<https://drive.google.com/file/d/13zvEciv1Rq6aI-5LSt-9Fg-p2XC2rMOQ/view?usp=sharing>.
The output is here
<https://t.yesware.com/ta/fcc4dc28c3803f84e9fb06bb6730ebb57f2ea738/6c27f7a69a8bb8935ffe348f6d687c23/40629b4359c106c7424a7a7b899ab4a9?n=here&yta=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1yymtHkUc2GcIBj2Fcboysird8YmppKWb%2Fview%3Fusp%3Dsharing>
.

Does anyone know why the output video slows down in the middle? Because
when I view the input file, the "slow down in middle" issue does not happen.

Thanks!
Henry
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