I finally found 2 ways for this.
1. Using avisynth + virtualdub
Following poisondeathray’s suggestion, Install the following:
Suppose our purpose is to convert “test.mts”. We first create a .txt file and write the following command:
Then, rename the extension from .txt to .avs to refer to avisynth. Then, open the .avs file in virtualdub and choose file->export->image sequence.
The other solution is using Blender.