If you downloaded a video from a blog(or somewhere else) and couldn't play it properly, chances are that the video file is actually a dummy(fake) file and that the uploader just made some money off of you downloading those file.
If you want to avoid this in the future and discourage those uploaders from creating more fake files, here's what you should do.
What you need:
-An hexadecimal editor
There are plenty available for free, but since the one I use isn't, I can't really recommend one. But for this use, any of them will do the job.
The 3 steps:
1. Download the first few MB of the first link(if it has multiple links).
2. Open that file with the hexadecimal editor of your choice.
3. Analyze the file content(this is the most complicated part, but is still pretty easy).
Some informations about the files(not essential):
A normal video file will have what is called a header which is the part where some information about a video is stored and this is usually followed by an empty block(represented as a bunch of 0).
If the video is in an archive file(.rar, .7z, etc.), there will also be a header for it but the rest will be the same as the video if there wasn't any compression used(which is usually useless with video file and fake file would be compressed to almost nothing so compression is never used on them).
Here's an image comparing a video file with the same video, but in an archive file:
(the left column is the address of the data inside the file, the middle one is the data in hexadecimal form and the right one is the data in ASCII(text) form)
mkv-rar_compare.jpg
The selected text is the video header so everything before it in the rar file is the rar header.
What's important in trying to detect a fake file is what comes after this.
How to tell if it's fake or not:
There are 3 types of fake files:
- An empty file(the hexadecimal portion is filled with 0's after the header)
- A file filled with a pattern(x number of hexadecimal characters(usually less than 20) are repeated over and over again for the whole file after the header)
- There could also be a 3rd type where the file would contain all random data or simply be the wrong video, but there is no way to tell without downloading all of it. But luckily, they don't even bother doing that most of the time.
The empty file is very easy to detect since there's only 0's everywhere. Just scroll down for a while and if you only see 0's then you know it's fake.
The pattern one is a little harder to detect since it looks like there is something in the file, but if you scroll down rapidly, it's usually very easy to see the pattern repeat itself and that tells you it's fake.
Here's a comparison of an empty fake file and an actual video file:
(Empty fake file on the left and actual video on the right)
fake-real_compare.jpg
I skipped over 2 empty blocks(you can tell where with the address column) in the real file, but the rest is all filled with random data as opposed to the empty file which only has 0's.
That way you don't have to finish downloading any of the files so it won't give the uploader any money and if everyone does this, he'll hopefully realize that it's a waste of time to upload fake files.
I'll try to also add an example of a fake file with a pattern next time I see one(if someone finds one, please let me know).
If you have questions, commentaries or suggestions, don't hesitate to ask here.
.....OR.....we could talk some more..."
