RAR is 3x larger than its content

[PaulDNNS]

I've downloaded a couple of RAR files and noticed something very strange:

File1.rar: 1.94GB
Video1.TS: 1.92GB
Readme.rtf: 1KB


File2.rar: 1.94GB
Video2.MP4: 627MB
Readme.rtf: 1KB
File2.rar is supposed to contain Video2.TS, an HD video file, but it mistakenly contains Video2.MP4, a lower resolution version of the same video.

The thing that is totally baffling me though is that the compressed .rar file is 1.94GB, the size that it would have been if it contained the HD video, but its contents are only 627MB. There are no hidden files, nothing weird about it (apart from the obvious.)

So the question is, how is this even possible?

[HaQue]

strange for sure.
maybe have a look at all the options of the CLI version of rar.exe and see what testing/reporting options there are to see if anything sheds some light. also, I don't think so, but maybe look at alternate file streams. They aren't self-extracting rar files, .exe?

[data-medics]

RAR and ZIP files can be spliced to other files types to create hidden archives. Though usually it's done the opposite way, a jpg or other file which when renamed to RAR contains a hidden archive of data.

Try renaming the file to other media types and see if it opens. Perhaps they spliced the archive to a video file or something else.

[fzabkar]

FWIW, I created a small RAR with WinRAR and then used a hex editor to add zeros to the end of the RAR. Both WinRAR and 7Zip were still able to extract the original file and neither complained that the RAR was corrupt or "wrong" in any way.

Perhaps you could cut the RAR file in half with a hex editor (eg HxD freeware) and then see if 7Zip or WinRAR still manage to extract the MP4.