Video play speed is changed when streaming multiple mp4 files

I’m using python to live stream multiple mp4 video files with rtsp.
I’d like to provide video in sequence, so I used timeout for every second to catch eos (on_eos is not emitted, so it’s detour), when the first video is closed to eos,

  1. set pipeline state to null
  2. change location of filesrc
  3. disconnect and reconnect demux to link
  4. set pipeline state to paused
  5. set pipeline state to playing

Problem is that the second video is loaded successfully but its play speed is to fast.
multifilesrc is not working at all…

What should I do? please help me…