[fritsch]

Kodi is among very few audio player on Android world capable of outputting float. I can disable this float as it might make issues in general cause the float -> int mapping in Audiotrack itself might be problematic (so let it be done by kodi). I will post you an apk later on where you can verify this. Btw. make sure to set again your sink to 44.1 khz Stereo so that we resample and not this low quality Audiotrack under the hood.

[fritsch]

Is building here: http://jenkins.kodi.tv/job/BuildMulti-Android/68/

You don'T (!) need to force 44.1 / 2 channel - I plain disabled 44.1 entirely so that kodi resamples for you.
After it is finished you can download the result here: http://mirrors.kodi.tv/test-builds/android/ choose arm-v64a or arm depending on what you want to use.

With this code (at least I hope so) AudioTrack should not make anything on its own - but to be honest - one never knows what such sound servers do under the hood :-( - let's see

Edit:
Arm64-v8a: http://mirrors.kodi.tv/test-builds/andro...64-v8a.apk <- should work on your shield

[elee532]

Set kodi to 44.1 khz fixed 2 channels. Resample to highest.

I have looked, but I can't seem to figure out where this setting is. Can you help? Thanks!

[fritsch]

Just try my test build , please.

[wesk05]

Just try my test build , please.

It outputs everything at 16-bit 48kHz. Is that what you intended? I will post some FFTs soon.

In the image below are 9 FFTs done on the original test tones and HDMI capture PCM outputs. The X-axis has been plotted on a linear scale. The test tones were 1sec. sine sweep at -12dBFS (16-bit 44.1kHz, 24-bit 48kHz & 24-bit 192kHz). In the plot legend Kodi 18 means Kodi 18 nightly build, Kodi Int means this test build. FFT size 65536 & Kaiser-Bessel window (140dB).


Click on the plot for full size image.

Based on the FFTs, it doesn't look like this test build is better than the master build. Oh, I also found out that the Shield doesn't output 24-bit 48kHz. 24-bit outuput is only for sampling rates above 48kHz!

[fritsch]

No the testbuild will output every sample rate available but not 44.1 khz. So in this build kodi will automatically resample 44.1 to 48.0 khz. Furthermore I disabled Float output entirely - so that kodi can do the internal float integer calculation on its own and does not rely on Audiotrack here again.

[fritsch]

Just try my test build , please.

It outputs everything at 16-bit 48kHz. Is that what you intended? I will post some FFTs soon.

In the image below are 9 FFTs done on the original test tones and HDMI capture PCM outputs. The X-axis has been plotted on a linear scale. The test tones were 1sec. sine sweep at -12dBFS (16-bit 44.1kHz, 24-bit 48kHz & 24-bit 192kHz). In the plot legend Kodi 18 means Kodi 18 nightly build, Kodi Int means this test build. FFT size 65536 & Kaiser-Bessel window (140dB).


Click on the plot for full size image.

Based on the FFTs, it doesn't look like this test build is better than the master build. Oh, I also found out that the Shield doesn't output 24-bit 48kHz. 24-bit outuput is only for sampling rates above 48kHz!  

How does it compare to other operating systems, e.g. windows or Linux? Is there a difference? What do you see in above graph that directly relates to hearable bad audio quality? The only curve I see that would suck is the lower red one, cause in the hearable range it goes down way before 20 khz.

[wesk05]

This is how it looks like on LE x86 (Milhouse build, Intel Haswell). Where is this 5dB difference coming from? I did make sure that volume was set to 100%.



The topmost curve is 192kHz test tone, the blue curve below it is Kodi output, the two curves below the blue one are test tones 44.1/48 kHz, the next two curves are Kodi 44.1/48 kHz output.

No the testbuild will output every sample rate available but not 44.1 khz. So in this build kodi will automatically resample 44.1 to 48.0 khz. Furthermore I disabled Float output entirely - so that kodi can do the internal float integer calculation on its own and does not rely on Audiotrack here again.

Well... AudioTrack is outputing everything as 16-bit 48kHz.

[elee532]

Just try my test build , please.

 Hi @fritsch, pardon my ignorance, but I have not idea how to install a test build on the Nvidia Shield. Can you provide me with some direction? Thank you!!

[wesk05]

Just try my test build , please.

 Hi @fritsch, pardon my ignorance, but I have not idea how to install a test build on the Nvidia Shield. Can you provide me with some direction? Thank you!! 

Download the apk to your PC, transfer the file to the Shield or use a USB flash drive. Then use a file manager like X-plore to install the apk.

[elee532]

Where is this 5dB difference coming from? 

 I have as much as a 15dB difference! It's only above about 2KHz where Kodi output starts to look normal.

[elee532]

Download the apk to your PC, transfer the file to the Shield or use a USB flash drive. Then use a file manager like X-plore to install the apk.

Thanks "fritsch". This is super helpful. I'll give it a try this afternoon and report back.

[wesk05]

I have as much as a 15dB difference! It's only above about 2KHz where Kodi output starts to look normal. 

You are recording your speakers with a microphone which is going to introduce external variables. I am just looking at the PCM output.

[fritsch]

This is how it looks like on LE x86 (Milhouse build, Intel Haswell). Where is this 5dB difference coming from? I did make sure that volume was set to 100%.



The topmost curve is 192kHz test tone, the blue curve below it is Kodi output, the two curves below the blue one are test tones 44.1/48 kHz, the next two curves are Kodi 44.1/48 kHz output.

No the testbuild will output every sample rate available but not 44.1 khz. So in this build kodi will automatically resample 44.1 to 48.0 khz. Furthermore I disabled Float output entirely - so that kodi can do the internal float integer calculation on its own and does not rely on Audiotrack here again.

Well... AudioTrack is outputing everything as 16-bit 48kHz.  

 As the Audio-Engine is 100% the same ... it's introduced AFTER kodi ... in our kodi sinks no processing at all takes place. The sinks just add the stuff to the Audiotrack sink. On LE it seems you output 44.1 khz directly. On LE SNE32 is used, which kodi is internall mapping to from the decoded floatp. On Android this exact same float is ending in the "audiotrack" - from here the system (Android) does what it wants ...

Btw. that it has to resample 44.1 khz to something is btw. the killer for most music files around there and if it does shitty resampling under the hood ... just forget it as a music player ...

Edit: On Linux kodi, we only control our internal volume. Make sure the output device you are using is set to 100% as well. Use amixer or alsamixer to verify that. From the looks the curve is perfect - as in: nothing missing while the android one (especially the red one) seemed to have done something with the data in a horrible way.

[Hitcher]

Just try my test build , please.

 Hi @fritsch, pardon my ignorance, but I have not idea how to install a test build on the Nvidia Shield. Can you provide me with some direction? Thank you!! 

Get the Kodi Android Installer addon and simply navigate to the test builds.