answered
2019-05-11 15:45:53 +0200
So.. support for multiple bluetooth A2DP audio codecs (including AptX) is being worked upstream right now. It is partly done/merged, and some bits are still missing or work-in-progress currently (as of writing this, 2019-05-11). You can basicly "split" the required work in two main parts:
1) bluez support for multiple bluetooth A2DP audio codecs. Bluez needs to be able to discover/negotiate/parse different codecs, transport them, offer ability to choose/switch active codecs, remember last used codecs during BT reconnects, etc. Bluez does not need to actually encode/decode audio for these codecs, that's the job of bluez clients (like Pulseaudio), because bluez basicly just "transports" the encoded audio. This bluez work is mostly done and merged to upstream bluez git repository (in master branch, not yet in any released version). You can see the merged A2DP multiple audio codec patches here (commits after Dec 2018): https://git.kernel.org/pub/scm/bluetooth/bluez.git/log/?qt=grep&q=a2dp
2) Pulseaudio support for multiple bluetooth A2DP audio codecs, and ability to utilize the bluez provided support for handling multiple A2DP codecs. Pulseaudio is the client for bluez, so it's pulseaudio who must be able to encode/decode audio using various codecs, which means Pulseaudio needs to use various codec libraries to encode/decode audio using different codecs, and allow end-user to choose/configure which codec to use, etc. Currently the "groundwork" patches to support multiple A2DP audio codecs in Pulseaudio has been merged (during the last month or so), but the actual support for LDAC, AptX-HD, AptX, FastStream, and high-quality SBC codec is still a work-in-progress. More review and testing is needed to get the rest of the patches merged to upstream Pulseaudio. Currently the remaining pulseaudio patches are at 10th revision atm. You can find the patches for example here: https://lists.freedesktop.org/archives/pulseaudio-discuss/2019-May/031100.html (from: https://lists.freedesktop.org/archives/pulseaudio-discuss/2019-May/ ).
BT A2DP multiple audio codecs development work is mostly done by developers Pali and Luiz. You can find the discussions/reviews/patches on linux-bluetooth and pulseaudio mailing lists.
audio codec libraries used/required:
- https://github.com/pali/libopenaptx
- https://android.googlesource.com/platform/external/libldac / https://github.com/EHfive/ldacBT
Yes! I agree with you! apt-x would be awesome function to Jolla in order to keep it as premium device (for high-end enthusiasts)
LaruX ( 2014-01-06 14:38:53 +0200 )editWhy would you ask for propietary extensions on a phone that stands out as being one of the most open platforms?
WhyNotHugo ( 2014-07-08 18:15:18 +0200 )edit