Audio dropouts with some cars

[kadimgh]

I'm experiencing frequent audio dropouts in my Mazda CX-5 (2021). The issue is intermittent, but on average happens 1-3 times per minute. AA wired works without dropouts in the same car

At the same time Mazda 3 (2018) works much better averaging 0-1 dropouts per 30 minutes

Hardware: Raspberry Pi 4
WiFi: 5GHz channel 36
SW: aa-proxy-rs 0.7.0
Phone: Pixel 3a XL, Android 12

I've also tried other experimental builds (nisargjhaveri/WirelessAndroidAutoDongle#217 (comment)) and radio configurations, but the issue seems to follow the car

[manio]

The issue is intermittent, but on average happens 1-3 times per minute

Yeah, something’s definitely off. For me, it only happens maybe twice during a one-hour drive. I’d say it’s probably due to Wi-Fi interference with Bluetooth - it usually happens when I’m using Bluetooth to pull OBD data at the same time.
I'm running it on a Raspberry Pi 02w, which is a much weaker board, so that could also play a role.

I've also tried other experimental builds (nisargjhaveri/WirelessAndroidAutoDongle#217 (comment)) and radio configurations, but the issue seems to follow the car

That experimental build has now become official: aa-proxy-rs releases. You could try the latest version, but if the experimental one didn’t work for you, I wouldn’t expect a huge difference - still, might be worth a shot.
I’m guessing you’re using passthrough mode (not MITM), right?

You didn’t mention your phone, but maybe try testing with a different brand or a newer device if you can - just to play around with the setup and narrow down the issue.
You could also hop into our Discord and ask the community - I'm pretty sure someone out there is using a Pi4 and can share how it’s working for them...

[kadimgh]

I’m guessing you’re using passthrough mode (not MITM), right?

yes

You didn’t mention your phone, but maybe try testing with a different brand or a newer device...

It's Pixel 3a XL, which is now ~6 years old and was a budget phone to start with. I don't have a different Android device to try at the moment. I understand the phone might be involved in the issue, but I just wanted to highlight that there is a setup that works without issues (with Mazda 3), so it is worth to have the issue logged here as a known issue

You could try the latest version...

I'll try 0.8.0 and report if there are any improvements

[kadimgh]

0.8.0 behaves the same as 0.7.0 for me

One additional thing I've noticed is that dropouts happen at intervals divisible by 20 seconds. For instance at one of the songs dropouts happened at 0:12, 0:32, 1:12, 2:12. I've noticed this pattern on several songs and I don't believe it's a coincidence. Is there any blocking code by any chance running every 20 seconds in aa-proxy-rs?

[manio]

@kadimgh
Can you please try this image?
https://skyboo.net/temp/aa/joka90/rpi02w_sdcard.img
It's AAWirelessDongle based.

[kadimgh]

@kadimgh Can you please try this image? https://skyboo.net/temp/aa/joka90/rpi02w_sdcard.img It's AAWirelessDongle based.

I only have RPi4, I don't have RPi02w. Is there an image for RPi4? I've checked https://github.com/joka90/WirelessAndroidAutoDongle but could not find SD card images there, I can probably build one myself if that's what expected

[manio]

I built it only for RPi02W. Do you like to build it yourself or you like me to try?

[kadimgh]

luckily there is a docker build, I'll try myself and report back if there are any issues

[manio]

I was also using docker, but to build it you also need to run this inside container before build:
sudo apt install libelf-dev

[kadimgh]

I was also using docker, but to build it you also need to run this inside container before build: sudo apt install libelf-dev

I've built the main brunch of joka90 fork and installed on my RPi4, but unfortunately I can reproduce the "audio dropout every 20 seconds" with it even more consistently compared to aa-proxy-rs 0.8.0

Here is the SD card image if anyone is interested

[manio]

Ok... this is only confirming that the source of dropouts is probably a phone (or this specific raspberry for some hardware reason?). Ideally if you could ask anybody (friend, family) to pair with the dongle and do some testing...

[kadimgh]

Ok... this is only confirming that the source of dropouts is probably a phone (or this specific raspberry for some hardware reason?). Ideally if you could ask anybody (friend, family) to pair with the dongle and do some testing...

I acknowledge that the phone might be the part of the root cause. But then again it works fine in a different car

I've also tried a workaround with MITM and disabling Media and TTS sinks in the config. The audio stayed on the phone, while I could still see the music player UI and control the playback (but not the volume) from the car controls. Unfortunately in such configuration HU choses to use Phone BT profile rather than Phone+Audio, so the audio does not get routed over BT to car speakers. And if I force to switch to Phone+Audio on the HU, then it disconnects Android Auto:

I'm thinking of trying AAWireless and see if it reproduces the same issue or not with my car and phone

[manio]

Yeah good idea if you have such possibility, but keep in mind that AAWireless is based on different hardware and software (version TWO is using 5GHz WiFi for sure). Thinking this way you could also try other raspberry with 5GHz band :)

[kadimgh]

I've got a no-brand $30 dongle from Amazon, likely based on Allwinner v851 SoC + 5GHz radio and so far it worked without dropouts with the same phone and car that aa-proxy-rs + RPi4 were having issues with. I realize this is not very actionable, but just another data point

[lasanthax]

Hi All,

I have a theory regarding audio dropouts; I am using a Pi 0W as well. This issue seems related to external interference. For example, every time I pass a specific section during my daily commute, it worsens, particularly at a major tram intersection that has a high EMF field.

Additionally, new cars with SMART/KESSY constantly search for their keys at certain intervals, which may also cause some interference. Furthermore, the built-in WLAN on the head unit might be contributing to the problem.

To investigate further, I need to:

• How to disable the head unit's WLAN (VW Golf MK7.5)

• Explore shielding the Pi with aluminium foil stickers or moving it away from the centre console (where the SMART/KESSY reader is located)

• Disable the Pi's Wi-Fi and add a USB Wi-Fi+Bluetooth dongle to see if this resolves the issue. (not sure if this is possible)

I will keep everyone updated if there are any positive outcomes related to audio dropouts

[manio]

One additional thing I've noticed is that dropouts happen at intervals divisible by 20 seconds

Look here: https://www.androidauthority.com/android-auto-stuttering-music-3597082/
"Everything worked fine until August 27, when their music started skipping every 20 seconds"
Sound familiar? :)