Le quartidi 4 floréal, an CCXXIII, Carl Cynthia a écrit :
> These link reference the fact that VDH is now using libav for his current
> converter. Again, you can download a copy yourself if you add the addon to
> Firefox and e.g. attempt to download a Youtube video at certain quality
> settings. You will only find out about the need to register (and this will
> also be your first clue as to the fact that libav has been modified
> without prominent disclosure) after downloading a video with the converter
> running.
> 
> http://www.downloadhelper.net/about-licensing.php
> http://www.downloadhelper.net/install-converter3.php

If I understand correctly, there are three components here:

- The Mozilla extension.

- The locally installed copy of avconv.exe.

- ConvertHelper3Setup.exe.

The Mozilla extension does not seem to contain any code from FFmpeg/libav,
nor any binary resulting from that code. Its only relation with avconv is
that if the program is present (you said it: "you can download a copy
yourself"), it may try to use it. That does not make it a derivative works,
and therefore the extension is not subject to the GPL, it can have a
proprietary license with as much DRM and other user-unfriendlyness they
want. Users just need to refuse it.

The locally installed copy of avconv.exe... depends on where you got it,
which leads to:

ConvertHelper3Setup.exe: the README.txt file says:

# ConvertHelper is a Windows build of Libav (https://libav.org/), copied from
# http://builds.libav.org/windows/release-gpl/ as of 2015-03-03,
# and packaged (with Inno5, http://www.jrsoftware.org/isinfo.php) to be easily
# installable on a Windows platform.
# 
# Source code for this release of Libav can be downloaded from
# http://www.downloadhelper.net/libav-11.2.tar.gz

It seems to me it respects the GPL more-or-less (clause 3b; there is the
"valid for at least three years" clause, but the formulation is vague).

And this "Inno5" seems to be even Free (BSD-ish). But even if it was not, it
would be similar to compiling the project with a proprietary compiler, which
is not considered a problem.

Do you have any reason to believe that the copi of avconv embedded inside
ConvertHelper3Setup.exe was actually modified? IMHO, it would be pretty
stupid to distribute a modified copy with restrictions but accompany it with
a link where you can download a pristine copy. This kind of trick can work
if you want to install spyware or such, but not to get people to pay for it.

Therefore, I do not believe there is a GPL violation at work here.

Of course, downloadhelper is still a very proprietary software, and as such
should be shunned by all people who like to be Free.

One last remark: Mozilla extensions are JavaScript packet in a Zip file. If
one asks for registration, it is always technically possible to unpack it,
change the JavaScript code to remove a license check and re-pack it. The
same is possible with compiled binaries, but with JavaScript code it is
usually much easier, especially if it has not been obfuscated. Depending on
your country, and provided you do not distribute the result, it may even be
legal.

Note that I am just stating a general fact, not advising you to do it on any
particular proprietary extension. I advise you not to use proprietary
extensions.

Regards,

-- 
  Nicolas George

Attachment: signature.asc
Description: Digital signature

_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel

Reply via email to