You must set the threshold of the tool to $0.0$.
open with an editor, and see the hidden white plain text.
convert and play it.
As you can find with
strings, this is a
H.265/HEVC codec coded video.
So I tried simply below, and it succeeded.
$ ffmpeg -i out_743a4e0cbbfae017e5197b303c82aa52.raw out.mp4
Find the string
flag, you can get the base64-ed
flag.zip from the SMTP packets.
Then find the string
password, you can get the string