Place imported video clip onto the timeline and then attempt to change MPEG importer settings as below:

1) Choose [Settings] > [System Settings].
2) Choose [Importer / Exporter] > [MPEG] in the left-pane.
3) Attempt to modify the setting and playback timeline step-by-step.

a) Uncheck “Use Accel, Seek”.

b) Check “Get Timecode from GOP Header”.

c) Uncheck “A/V Synchronization Using PTS”.*
*If the imported video can be displayed by unchecking the option, the clip needs to be converted to an HQ file. Because, the option affects all MPEG clips in the timeline and audio and video may be unsynchronized by unchecking the option.

Steps to convert to an HQ file
1) Create a new sequence.
2) Uncheck “A/V Synchronization Using PTS” option.
3) Place only the MPEG clip that needs to be converted to an HQ.
4) Export to an HQ file.
5) Replace to the expored HQ clip at the original location in the timeline.