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f4exb / sdrangel

SDR Rx/Tx software for Airspy, Airspy HF+, BladeRF, HackRF, LimeSDR, PlutoSDR, RTL-SDR, SDRplay and FunCube
GNU General Public License v3.0
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dab audio stuttering on android #2139

Open held-der-arbeit opened 3 weeks ago

held-der-arbeit commented 3 weeks ago

Hi,

I try to use my rtl-sdr v4 with the sdrangel android app (7.17.1-1496-ge3d862c8a from google play store), unfortunately the dab audio is stuttering. Listening to dab music is not possible. The broadcast fm demod is working and fm music can be listened to.

To exclude rtl-sdr hardware and antenna issues I downloaded the 7.21.1 sdrangel app for ubuntu 22.04. On ubuntu 22.04 dab audio is working fine. I noticed that there where some changes on the dab module in 7.20.x. Unfortunately there are no apk files for the latest releases. When is the next release for android planned? Maybe this fixes the dab stuttering issue on android. Is there a guide available, how to get an android apk out of the sources in case there is no release planned?

If needed I can send also an audio recording and screenshots from the android app.

Thanks in advance.

srcejon commented 3 weeks ago

Some screenshots from the android app would be useful, showing your settings and signal.

What Android device are you using?

There haven't been any DAB changes that should make a difference.

held-der-arbeit commented 3 weeks ago

I'm using a Fairphone 5 with android 13, see screenshots below. Also on a different android 14 device I have this stuttering for dab. On both devices the AAC in the statistics only has around 60% - 70%. I did not change the default settings from the app, only selected the channel.

Screenshot_01 Screenshot_02 Screenshot_03

I hope this helps a bit.

srcejon commented 3 weeks ago

SNR looks low. Try adjusting the gain to see if that helps.

held-der-arbeit commented 3 weeks ago

Gain set to max (49,6) makes no difference, also clicking AGC next to the gain bar does not improve the situation.

srcejon commented 3 weeks ago

What does the signal look like on your PC that works?

held-der-arbeit commented 3 weeks ago

This is how it looks on the pc:

Screenshot_04

DAB audio is perfect on the pc. Version in use is 7.21.1.

[EDIT] I also had a try on an android 11 device, there is the same problem with stuttering.

srcejon commented 3 weeks ago

Not sure - one other thing to check would be if one of the CPUs is overloaded.

srcejon commented 3 weeks ago

Gain set to max (49,6) makes no difference, also clicking AGC next to the gain bar does not improve the situation.

Try turning it right down as well.

held-der-arbeit commented 3 weeks ago

Gain set to max (49,6) makes no difference, also clicking AGC next to the gain bar does not improve the situation.

Try turning it right down as well.

So 22.9 is the point where "audio playback" starts, below that to 0 there is no audio at all.

held-der-arbeit commented 3 weeks ago

Not sure - one other thing to check would be if one of the CPUs is overloaded.

So there are 8 cores in the system and top shows the following:

org.sdrangel %CPU 129.0 audioserver %CPU 17.0 audioserver %CPU 14.6

I would not read this as overload, as there are 8 cores available.

srcejon commented 3 weeks ago

Some parts of the demod are limited to a single core, unfortunately.

Hard to say if that is the problem.

held-der-arbeit commented 2 weeks ago

Hmm. I created a flame graph using perf for the sdrangel process running on the pc, unfortunately there is no perf on my android devices. Maybe you can identify some issue on it. The process was using around 45% cpu in top.

perf_sdrangel_pc

How are you building the app for android? I tried to use qt creator, but unfortunately it will not compile.