Lolik wrote: ↑Mon Jan 11, 2021 2:18 pm
---
A proposal for the "big question" : does and/or can Neutron make sure that allegedly supported sampling rates aren't downsampled before the DAC ? Can it check whether the os resamples ? Can it ask the DAC what sampling rate it gets ?
There is no big question really. Neutron can not know (and any other apps too) what is the real final output frequency. OS does not provide such API.
All we can do is to force hi-res format to the OS via OS API in hope that it will be accepted by the OS drivers (in normally it is successful).
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. The output audio driver is therefore very complex. If config is not accessible then user can tackle it by using the Generic Driver -> Custom Format option which helps to try to enforce hi-res output.
To check if you really have hi-res you could either use ADB command while playback is active and line-out is attached to speakers/headphone (some devices support hi-res only for line-out):
adb shell dumpsys media.audio_flinger
In the obtained log you need to find a DIRECT stream, if all are MIXER then there is no hi-res happening. Some devices do not reflect hi-res via audio_flinger dump, like Samsung S10 and higher and in such case you can employ really effective method which works for all devices:
1. Use Audacity (
https://www.audacityteam.org) audio app
2. Create sweep tone for the range of frequencies you wish to test
3. Play sweep tone with Neutron or any other music app and Record it with PC with Audacity at for example 192 kHz frequency
4. Do spectrum with Audacity for the recording and see what frequencies are available
Here is an example of Samsung Galaxy S10e sweet test:
https://twitter.com/neutroncode/status/ ... 5745920002
Some users who are using HDMI as output device see the output format on the receiver.
So these are the possibilities.
Please also note that some options may cancel hi-res output:
https://neutroncode.com/forum/viewtopic ... 811777ce94