limit on sampling rate for Bluetooth

[blaubär]

Yes,hi-res codec and hi-res speaker has been activated in generic driver.

Okay, and did Neutron before version 2.16 offer high-res-audio for the speaker ?

maximum outputation via device's speaker was 16 bit at 48 khz.Lack of high-bit output through the speaker is a constant problem in all versions of this player

If I understand you correctly, it doesn't. Then it would seem that your device doesn't support high-res-output for the speaker. I just checked it for my Samsung S9, it's the same there, I'll ask the developer about that.

[blaubär]

I tried it with another music player, and also only got 48 kHz ... so that might just be due to a change from Samsung.

20210214_190725.jpg (33.33 KiB) Viewed 6614 times

[tavrouss]

I do not think this change is due to Samsung, because of the neutron player operates independently of the operating system. So this error is related to the player.

[blaubär]

I do not think this change is due to Samsung, because of the neutron player operates independently of the operating system. So this error is related to the player.

No, Neutron can and does not operate independently from the operating system.

Assumption regarding the supported frequencies is made on the basis of OS internal config files for audio core which report frequencies and sample formats, some information for device families and SoCs is hardcoded, some device producers provided information regarding what format setup is need for hi-res (for example DAP producers) and etc.

Neutron tries to find out what sampling rates are supported by the os and only uses these. With the one exception: on Android with the generic driver you can override that in the custom format. Should you do that and then the os not support the sampling rate you chose then the os will resample to a supported sampling rate before the DAC.

[tavrouss]

If neutron can not operate independently,what is the meaning of this:

Its reliable, platform independent, native core provides consistent behavior on all devices.

[blaubär]

If neutron can not operate independently,what is the meaning of this:

Its reliable, platform independent, native core provides consistent behavior on all devices.

No application can operate independently from the operating system. The os set the limits and provides the resources. Given the same limits and resources Neutron will give the same results. The sampling rates aren't necessarily the same on different platforms, so Neutron doesn't necessarily offer the same sampling rates on different platforms.

[blaubär]

Then it would seem that your device doesn't support high-res-output for the speaker. I just checked it for my Samsung S9, it's the same there, I'll ask the developer about that.

I got the following answer from the developer:

Samsung never supported hi-res Speaker in hw, so Neutron was doing that by mistake and thus multiple resampling was happening. It was rectified and 16/48 looks fine for this case.

So a sampling rate of 48 kHz and a bit depth of 16 bit are correct for the speakers.

[tavrouss]

another question.now I am playin music and neutron mp shows that outputation is 24 bit at 96 khz.but when I open device's setting>developer options>networking , it shows these informations:
Bluetooth audio codec:AAC
Bluetooth audio sample rate:44.1 khz
thus,which is correct:1-16 bit at 44.1 khz or 2-24 bit at 96 khz ????

[blaubär]

another question.now I am playin music and neutron mp shows that outputation is 24 bit at 96 khz.but when I open device's setting>developer options>networking , it shows these informations:
Bluetooth audio codec:AAC
Bluetooth audio sample rate:44.1 khz
thus,which is correct:1-16 bit at 44.1 khz or 2-24 bit at 96 khz ????

That means that the operating system's bluetooth input accepts 96 kHz / 24 bit, so Neutron can offer that to you, and you chose to deliver high-res-audio to the bluetooth input. Your device uses the AAC codec with 44.1 kHz sampling rate, so the 96kHz transferred by Neutron to the BT input will be downsampled to 44.1 kHz there. If you don't want that you'll have to tell your device to use another BT codec that supports 96 kHz, e.g. LDAC. This will only work if both the device and the BT on the other side ( headphones etc ) support this codec.
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Alternatively it might be a good idea to tell Neutron to use 44.1 kHz, especially should you play music with that sampling rate.

[dmitrykos]

After recent update we are limited to Bt 24 bit 96khz sampling rate . Why ?
I was. Able to get 32bit 192khz sampling over generic driver with haylou t15 and sounded really good why. Are we going backward ? At least leave us an option to unlimit with our risk of anything ?

Bluetooth A2DP does not support anything higher than 24/96 format (https://en.wikipedia.org/wiki/List_of_codecs#Bluetooth), therefore this limit prevents users to misuse the format that will cause double re-sampling: Neutron upsamples -> OS downsamples to some supported frequency.

blaubär is correct with comment how it works: Neutron provides possibility to the OS to use hi-res format and send it as is. For example if OS supports LDAC (it became a part of AOSP Android source by the way by the decision of Sony) then it can transfer 24-bit with 44100 - 96000 frequencies to your LDAC headphones.

There is no guarantee though that it will happen for sure because Android's audio API is limited in this sense and there is no reliable feedback from it, so you need to re-check the result using indication of headphones or BT DAC (for example Qudelix 5K has companion app which shows the format in which device is receiving the signal).