Please allow me to ask another newbie question.

I am trying to merge video files with FFMPEG using "CONCAT" command. I often get a warning message saying:

"[avi @ 000000020d17cfbc0] sample size (1) != block align (2)"

What does this mean? Is this something I should be concerned (e.g., an error that could affect the output file)?

I would appreciate if you could help me deal with this potential issue. Thank you in advance.