[pulseaudio-discuss] SBC XQ for PA 13.0

[Andrey Semashev]

On 2019-12-07 22:31, Pali Rohár wrote:
> On Saturday 07 December 2019 22:13:28 Andrey Semashev wrote:
>> On 2019-12-07 21:30, Pali Rohár wrote:
>>>
>>> FDK-AAC library is incompatible with any version of the GNU GPL license
>>> and therefore it is not possible to use it in any GPL licensed software,
>>> like pulseaudio. See: https://www.gnu.org/licenses/license-list.html#fdk
>>
>> Well, incompatibility means the resulting binary is not redistributable.
>> Users could still build PA with libfdk-aac locally.
> 
> Yes, you are right.
> 
>> Or the library could be
>> loaded dynamically, if present on the user's system, without having to link
>> with it at build time.
> 
> Some people says that this is not legal too. Loading library either at
> build (link) time is same as at runtime... And FSF has similar
> explanation. Main problem is that license of external library does not
> allow you to use it in your application. And it does not depend on how
> you build your application or how you use that library (dlopen or
> stating or dynamic linking). You are still usage same library API. But
> I'm not lawyer...
> 
> Important it that if there are people who doubt about regular usage then
> such functionality would not be included into distribution. And above
> dynamic loading via dlopen is a reason for doubt that something is not
> there fully legal and can be problematic.
> 
>>> If there is other AAC library which license allows usage it in
>>> pulseaudio then it could be possible. Just somebody needs to write it.
>>
>> The built-in implementation in ffmpeg is under LGPL 2.1, which should be
>> compatible.
> 
> Yes, LGPL 2.1 is fine.

One other question regarding libfdk-aac. Would it be ok to try using it 
through ffmpeg if it is built with it? If ffmpeg is compiled without 
libfdk-aac then we would fall back to the built-in encoder.

This would allow people who build ffmpeg themselves to use libfdk-aac. 
On the PA side, this would require very little change code-wise (it 
would not introduce build dependency on libfdk-aac), most of the 
integration with ffmpeg remains the same.