Some THM Others MVI!!

Ok so I am having some issues with trying to view video clips from my SD card I took out of my CANON POWERSHOT A470

Some of the video clips are in MVI format while others are in THM format (which I already know is a thumbnail)

I cannot view the clips in THM format!! My question is why would some of my clips be unreadable but others readable!!

How can I change it!! And please reframe from explaining what the files are as I already know I just can`t figure out how to change it so I can view all of the clips

Thanks in advance!!

The videos are actually in AVI format using the M-JPEG codec (is that what you meant by MVI?). The THM files are thumbnails and as such are not videos themselves. They are a picture that represents the AVI video file with the same name. If I understand your question you are thinking the AVI and THM files represent different videos. They don’t. Each AVI file has a THM file of the same name. If you want to view the video you play the AVI file (which almost any multimedia player will - like Windows media player). The THM is just a picture, not a video.