Bluetooth codecs in 2021, which one to pick

FranceBB · 2nd April 2021, 13:54

Hi there,
although I'm very familiar with normal audio codecs like AAC, AC3, AC4, Opus, PCM, Vorbis etc, I'm not really familiar with bluetooth codecs.
Here is the thing, when I connect my bluetooth headsets, the computer is asking me which codec to use among the following using the A2DP Sink:

- SBC
- AAC
- aptX
- aptX HD
- LDAC

It doesn't specify anything like bitrate, sample rate, bit depth etc, so I have no idea about the specs, which annoys me... a lot.
Doing a bit of research, it looks like all of the support the output of my sound card setting, so 48'000Hz passthrough (with 44100Hz resampled automatically to 48kHz), however not all of them support 32bit (which is my output).
If I got that right, it should be:

SBC: 16bit 48'000Hz 345kbit/s CBR 2ch Stereo
aptx: 16bit 48'000Hz 384kbit/s CBR 2ch Stereo
aptX HD: 24bit 48'000Hz 576kbit/s CBR 2ch Stereo
LDAC: 32bit 48'000Hz 990kbit/s CBR 2ch Stereo

So, although I don't know the codec implementation, what's their psycho-acoustic, which transform they use etc, it looks like LDAC is the clear winner here as it's the only one that can actually output a 32bit precision stream. I also gladly noticed that it uses a modified version of the classic DCT, so it looks good. I actually tried to listen to those codecs myself and although I wasn't able to hear any difference between aptX HD and LDAC while playing AAC radio stations like BBC Radio 1 or Capital London or YouTube Music, but I was able to hear the difference while playing commercially available PCM files from CDs. So... should I just pick LDAC and go ahead with it?

I'm sorry for all those questions but I'm really not familiar with bluetooth codecs...

tebasuna51 · 2nd April 2021, 15:23

Is normal don't hear differences with these bitrates, I recoded to flac a Cat Stevens CD and I obtain an average bitrate of 792 Kb/s, for stereo sources AAC encodes at 192 Kb/s are considered transparent.

aptx and LDAC are proprietary audio codecs, if you have already pay to use it don't worry and use the best LDAC

hajj_3 · 2nd April 2021, 16:34

LC3 and LC3 Plus are new codecs which were added in Bluetooth 5.2: https://www.iis.fraunhofer.de/en/ff/...ation/lc3.html

I don't know if any headphones are out yet that support bluetooth 5.2 yet.

FranceBB · 2nd April 2021, 19:24

Quote:

Originally Posted by tebasuna51

aptx and LDAC are proprietary audio codecs, if you have already paid to use it don't worry and use the best LDAC

Got it. I'll stick with LDAC then.

Quote:

Originally Posted by hajj_3

LC3 and LC3 Plus are new codecs which were added in Bluetooth 5.2.
I don't know if any headphones are out yet that support bluetooth 5.2 yet.

Dunno, but definitely not mine, otherwise it would have been listed in the option.
Anyway, I'll stick with LDAC which is the best one I can pick with my bluetooth version, but thanks for the heads up anyway.

2nd April 2021, 13:54	#1 \| Link
FranceBB Broadcast Encoder Join Date: Nov 2013 Location: Royal Borough of Kensington & Chelsea, UK Posts: 2,904	Bluetooth codecs in 2021, which one to pick Hi there, although I'm very familiar with normal audio codecs like AAC, AC3, AC4, Opus, PCM, Vorbis etc, I'm not really familiar with bluetooth codecs. Here is the thing, when I connect my bluetooth headsets, the computer is asking me which codec to use among the following using the A2DP Sink: - SBC - AAC - aptX - aptX HD - LDAC It doesn't specify anything like bitrate, sample rate, bit depth etc, so I have no idea about the specs, which annoys me... a lot. Doing a bit of research, it looks like all of the support the output of my sound card setting, so 48'000Hz passthrough (with 44100Hz resampled automatically to 48kHz), however not all of them support 32bit (which is my output). If I got that right, it should be: SBC: 16bit 48'000Hz 345kbit/s CBR 2ch Stereo aptx: 16bit 48'000Hz 384kbit/s CBR 2ch Stereo aptX HD: 24bit 48'000Hz 576kbit/s CBR 2ch Stereo LDAC: 32bit 48'000Hz 990kbit/s CBR 2ch Stereo So, although I don't know the codec implementation, what's their psycho-acoustic, which transform they use etc, it looks like LDAC is the clear winner here as it's the only one that can actually output a 32bit precision stream. I also gladly noticed that it uses a modified version of the classic DCT, so it looks good. I actually tried to listen to those codecs myself and although I wasn't able to hear any difference between aptX HD and LDAC while playing AAC radio stations like BBC Radio 1 or Capital London or YouTube Music, but I was able to hear the difference while playing commercially available PCM files from CDs. So... should I just pick LDAC and go ahead with it? I'm sorry for all those questions but I'm really not familiar with bluetooth codecs... __________________ LUT Collection FFAStrans Videotek - AAA - SafeColorLimiter Last edited by FranceBB; 2nd April 2021 at 14:04.

2nd April 2021, 15:23	#2 \| Link
tebasuna51 Moderator Join Date: Feb 2005 Location: Spain Posts: 6,915	Is normal don't hear differences with these bitrates, I recoded to flac a Cat Stevens CD and I obtain an average bitrate of 792 Kb/s, for stereo sources AAC encodes at 192 Kb/s are considered transparent. aptx and LDAC are proprietary audio codecs, if you have already pay to use it don't worry and use the best LDAC __________________ BeHappy, AviSynth audio transcoder.

2nd April 2021, 16:34	#3 \| Link
hajj_3 Registered User Join Date: Mar 2004 Posts: 1,126	LC3 and LC3 Plus are new codecs which were added in Bluetooth 5.2: https://www.iis.fraunhofer.de/en/ff/...ation/lc3.html I don't know if any headphones are out yet that support bluetooth 5.2 yet. Last edited by hajj_3; 2nd April 2021 at 16:37.