On 2019-12-07 21:30, Pali Rohár wrote:
On Saturday 07 December 2019 21:09:04 Andrey Semashev wrote:
However, I can still hear compression artefacts on quiet or nearly silent
audio sections, which sound like high-pitch squeaking sounds. It can often
be heard on various music fade out sections. I don't know if this is
inherrent from SBC codec itself or is a deficiency of libsbc implementation,
or the headphones. These artefacts are my main complaint about SBC.
See very nice description about this problem https://habr.com/en/post/456182/
Probably your headphones cripple audio by filters when SBC is used...
Yes, I've read that. That is the reason why I suspect the headphones
might be the culprit, but I cannot be sure.
Which brings me to my question to PA developers. Would an addition of
support for AAC be possible?
My A2DP patch series brings new pulseaudio API for implementing new A2DP
codecs. So yes, additional support for other A2DP codecs with my patch
series is possible. My patch series contains support for aptX, aptX-HD
and FastStream A2DP codecs.
Are your patches available in a PR or a git fork somewhere? If I'm going
to give it a try to add support for AAC, how can I get the up to date PA
version to develop against?
But... you need a library for encoding and decoding that codec ...
pulseaudio-modules-bt uses libfdk-aac to implement AAC, and if possible, I
would prefer that library as it provides the best quality available on
Linux. However, if licensing is an issue, there is also a built-in
implementation in ffmpeg.
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. Or the library could
be loaded dynamically, if present on the user's system, without having
to link with it at build time.
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.
_______________________________________________
pulseaudio-discuss mailing list
pulseaudio-discuss@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
