[FFmpeg-user] format_whitelist and fFMPEG command

[Moritz Barsnick]

Hi Dani,
why do you ask me and not the list? My rates are by the hour. ;-)

On Sat, Aug 08, 2015 at 21:39:14 +0000, Dani A wrote:
> Does the White_list switch forces the FFMPEg to look into the container to
> verify if it is mp4 or mov file?

ffmpeg always looks into a container, otherwise it cannot demux. You
can influence the way it does this with "-probesize" and
"-analyzeduration".

> I have used the white_list switch and I have renamed the a .mov file to .mp4
> and I tried to use the FFMPEG -white_list "Mp4", it went ahead with moving  the
> atom for the renamed file and I expected it will check the file content and
> then display an error as it is a mov file with a mp4 extension.

How do you move the atom by renaming? I don't get it.

Anyway: ffmpeg doesn't care for the extension (though it uses it as a
hint for the muxer, but not for the demuxer, I believe). It does check
the content.

Furthermore, if you had read the output quoted by me in the thread, you
would have seen that, from ffmpeg's perspective, mp4 and mov containers
are the same thing. ffprobe -show_format show this for both:

format_name=mov,mp4,m4a,3gp,3g2,mj2

In other words: ffmpeg doesn't know or doesn't expose the difference,
probably because the same demuxer is used. If what you're trying to do
is to fix the minor differences (which are in atoms apparently), you'll
need to do this pre-check for this detail outside of ffmpeg.
AtomicParsley comes to mind.

> So where is the security in the white_list command?

Define security.

Cheers,
Moritz