Hi,
I recently added an AV receiver in my setup hence enjoying movie/music stored on USB device attached to my RPI3. The problem only appears when playing music: randomly I have audio drops (<=1sec), nothing during a movie playback.
Kodi setting:
- adjust display refresh rate: really needed for smooth video, but not rate change visible on TV when playing music (sounds logic)
- Passthrough: NOT enable (so default) to be able to play movie w/o receiver ON
- music started from library (on attached USB disk via fstab)
Reading some topic about the issue, but did not yet found someone having music on USB and similar problem. However below what I tried:
-change HDMI cable: no change
-enable buffermode (Kodi 17 syntax): no change
-load test (maybe perf issue?): multiple copies via network or measuring the speed of the USB disk (dd) during a music playback. I’m not able to reproduce the issue in this condition
Yesterday I was by chance in front of my receiver when a drop occurred. The display shows somehow a lost of connection: the number of channels didn’t appeared anymore and come back after the drop. Following my read I saw 2 options but cannot tell if really applying to the issue:
- hdmi_clock_change_limit: with the adjust refresh rate in the video section it limits the change. But this is in video section, how can it apply to music only ?
- config_hdmi_boost: pushing the value to 7 seems help for long HDMI cable but mine is 2m long and the video playback is never affected.
And last information: I only played the last converted album, all in MP3 VBR. I used to convert file in MP3 CBR 320Kbps only then changed my mind as test. I don’t think it may be an issue, sometimes I play multiple songs without any drop then 3 in a minutes on the same album (really random, no particular song involved)
Thanks for the reading folks ;).
You say this started when you added your AV receiver. If you take it out of the setup temporarily do you have the same drops with the Pi playing music through the TV?
Well I should have been more explicit on this part: prior the AV receiver I rarely played music so it may be there since the beginning. I agree it worth the effort but it may be difficult to apply. The TV sound is weak and with music playing I’m not standing in the TV place all the time (remember the random behaviour)
But I’ll try 
I tried with the below settings changes
adjust display refresh rate: set to disabled
config_hdmi_boost=7
enable Kodi logging
No change, multiple songs w/o issue then 4 drops in 4min 
I have the kodi.log at disposal
Was that through your AV system or TV?
Could you please post the kodi log?
Update:
converted a set of MP3 VBR in CBR 320Kbps, same drop (just to confirm it’s not the file)
@yknivag I’m still using the AV receiver, didn’t take the time yet to test through the TV.
I can however confirm what can be called “loss of connection” on the receiver: The channels disappears and come back during the drop. A movie ran 2h yesterday through the same setup and never failed.
The Kodi log was taken with MP3 VBR, available HERE
May any entry of the config.txt be involved in such setting?
I connected in the past the RPI through the mini jack port for both image and sound. A blind guess so but as nothing seems to work 
Maybe something more simple (I don’t have config file under my hand now). For a last upadted RPI3 connected only through HDMI, what should the config.txt file look like?
Extracting the last image shows me only:
disable_overscan=1
framebuffer_depth=32
gpu_mem=16
I guess more are needed no? I wonder if the fact that the TV of is may not influence the behaviour.
RPI>AV receiver>TV, but TV off when listening audio. Maybe the below line may help somehow?
#Always force HDMI output and enable HDMI sound
hdmi_force_hotplug=1
Reply to myself;
no change with the added line, a new set of cable didn’t change anything neither 
So far I ended with DLNA access to the RPI (no drop through the network…) but face to empty category issue.