Sound glitches on some videos using iPad Pro + Sony 1WH-000XM4 via Bluetooth

[jebb76]

Hi all,

I'm getting frequent (every second or couple of seconds) sound glitches when playing videos on VLC 3.4.8 on an M1 iPad Pro using Sony WH-1000XM4 headphones connected via Bluetooth (using AAC-LC if I understand the Console.app output correctly).

Here's what I've tried so far to attempt to isolate the issue:
- Same headphones, same connection, playing music files via VLC works OK.
- VLC using the iPad Pro speakers or USB sound output works OK.
- Same headphones, Bluetooth, VLC on a MacBook Pro works OK.
- VLC on iPad Pro using a Bluetooth speaker also OK (this one however seems to be using SBC).
- Same headphones on same iPad over bluetooth, same file plays OK using Infuse.
- mkv files are all glitchy, so is an ogg file (video), but not the couple of avi files I've tried.
- Amazingly, the same movie plays OK as an .avi file, but glitches when I package it in an .mkv container (again, only over bluetooth - both play fine using other audio outputs).

Here are the log files for this last test:
- .avi file https://pastebin.com/3xFyCUTF
- .mkv file https://pastebin.com/Hrxy3M54 - obviously the multiple [WARN] underrun of xxxx bytes in the second one jump out.

Any hint at what might be happening, or something else I could try?

[fkuehne]

You'll have a fix for this in the next update. We know the cause and have a working improvement ready. Sadly, there is nothing you could change in the app to make it work for you in the meantime.

[jebb76]

Awesome! I'll make do with the USB DAC and wire connection in the meantime, now I know there's a fix coming. Thanks for the reply!

[fkuehne]

Would you be interested in testing a beta?

[jebb76]

Sure!

[fkuehne]

So Apple decided not to approve the beta in time for release, so you can try the new version from the App Store (3.4.9) starting today. Please provide feedback if it works correctly for you know. If not, we need a debug log.

[jebb76]

Just tested it, unchanged so far I'm afraid.

I've just done a couple more trials with an mkv file, and I'm only getting the glitches via NFS (server-independent apparently, the same from 2 very different machines) and playing the sound over Bluetooth. The same file played locally on the iPad is fine. Playing over SMB+Bluetooth is fine as well. And NFS + sound over the iPad speakers is also fine.

Here is the log from the glitchy playback:
https://pastebin.com/qLPwwMw1