I downloaded a couple Live FLV stream clips and certain parts of the video are jumpy/skipping for just a few secs and I have no problem using Avidemux or Avanti to convert these videos to MP4/MKV without audio (no need audio)...however I still see the few secs skipping/jumpy.

Is there anything I can do to improve or smooth out the jumpy/skipping part using filters? or other tools?

Original downloaded live stream clip:

Format : Flash Video (FLV1)
File size : 58.6 MiB
Duration : 20mn 48s
Overall bit rate : 394 Kbps

Video
Format : Sorenson Spark
Codec ID : 2
Duration : 20mn 48s
Bit rate : 372 Kbps
Width : 480 pixels
Height : 360 pixels
Display aspect ratio : 4:3
Frame rate mode : Variable
Bit depth : 8 bits
Stream size : 55.3 MiB (94%)