[Libav-user] FFmpeg License Violation - What Are My Remedies?

Michael Zucchi notzed at gmail.com
Fri Oct 12 11:02:38 CEST 2012

On 11/10/12 04:04, Matthew Lawrence wrote:
> I recently purchased an app from Google Play that incorporates the
> FFmpeg library.  Because the app is a derivative work under the
> LGPLv2.1, I believe I am entitled to a copy of the source code for the
> entire app.  I have e-mailed the developer's support staff, but they are
> refusing to release the source code.  I have cited the LGPL to them, but
> hey claim they are required to provide only the source code for the
> FFmpeg library.  I believe that they are in violation of the license and
> are violating both my legal rights and those of the FFmpeg team.

In essence, LGPL requires that you are able to 1: obtain the complete 
and compilable source code of the LGPL components they used (imo this 
wouldn't include any jni stuff and certainly not the application 
itself), and 2: replace the binary components of the LGPL compiled 
source (at least here in australia, compiled code has the same legal 
standing as the source itself - as it is only a machine translation of 
the original expression) - either the .so file or the .o files if it is 
statically linked - in the specific application you have installed.

Of course, apk's and the android shop are somewhat problematic wrt to 
the second point.  If you used the 'shop', then you actually got the 
application from google.  So you are quite entitled to ask google for 
the source as they were the ones who `distributed' or 'conveyed' the 
software to you.  They are required to supply source if asked for, and 
if they don't *they* lose the right to distribute it at all (which would 
cover the FFmpeg source components used - and impact on all 'apps' which 
used them).  The (L)GPL only comes into effect once distribution occurs, 
which is why you can do basically anything if you link with it privately 
- distribution creates all the obligations.  TBH i'm surprised they 
allow any of the (L)GPL licenses at all, since they don't even have a 
mechanism for distributing source and are thus automatically violating 
all L?GPL2.* source code regardless of whether the guys creating the 
apps are or not.

e.g. in the preamble:

"To protect your rights, we need to make restrictions that forbid 
distributors to deny you these rights or to ask you to surrender these 
rights. These restrictions translate to certain responsibilities for you 
if you distribute copies of the library or if you modify it.

For example, if you distribute copies of the library, whether gratis or 
for a fee, you must give the recipients all the rights that we gave you. 
You must make sure that they, too, receive or can get the source code."

Note this part says nothing about linking (that is the next sentence). 
It only says 'distribute' and 'distributor', an "app store" is 
definitely a distribution channel, as much as a cd or a yum server is ...

But they're richer than you: so, well, "sucked in" if you were the 
author, and as a customer you don't even get that much of a look-see.

The LGPL seems to be the most misunderstood of all the licenses, 
although quite why is a mystery - the language is quite clear and 
thoroughly explained.  One presumes much of it is just FUD for 
commercial gain.


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