Shipping a “high-end” equipment like the #Devialet #ExpertPro without #gapless #UPnP #DLNA support is just an embarrassment. Even my old #cyrusaudio streamer supported this!
Thanks for listening #Devialet. (3/3)

Digging further, it turns out the #ExpertPro is using the #Rygel #UPnP renderer.

But #Rygel has supported #UPnP since 2013/2014. So is the #Devialet #ExpertPro using an older version than that?! Weird since the UPnP support was added to Devialet around 2019-2020. (2/3)

Next issue with the #Devialet #ExpertPro: why doesn’t this thing support #gapless #DLNA #UPnP playback? A quick look at the exposed endpoints shows it’s missing SetNextAVTransport that’s required for #gapless play. 🧵 (1/3)

#ExpertPro behaves: no more #ZeroWindow packets. Note the somersaults of the #TCP window size: the #Devialet is literally begging for more traffic. Not going to get it, due to flow control on the #raspberrypi.
Goal achieved: no more interruptions when playing!

Conclusions? (8/9)

The #Devialet behavior when #DLNA #UPNP streaming from #minidlna running on #macOS is quite different and actually what I would expect.
#Devialet must not like #Linux #TCP stack?

#Devialet customer support provides no answer after 2 months. (5/9)

Turns out the #Devialet is telling the server to stop sending during the pause! It keeps sending #ZeroWindow packets, then eventually re-enables the send by opening its TCP window.
Now this starts looking like a problem with the TCP stack implementation of the #Devialet! (4/9)

A look at the network capture shows the size of the #TCP receive window of the #Devialet goes to 0 during the interruptions. Notice the see-saw pattern and the size of the #TCP window becoming quite large (~2MB), too large for such a device.
This is surely not possible?! (3/9)

The #Devialet device is used as a #DLNA #UPNP renderer and pulling content from a #minidlna server on a #raspberrypi (same LAN). The sound quality is gorgeous, until occasionally there’s no sound for 7-15s. This occurs mostly when streaming hi-res FLAC.
What’s going on? (2/9)

[Old hread reposted from a social media site I don't use any longer]
A thread about some high-end audio equipment with a low-end TCP stack implementation that pretty much makes the device unusable.
#Devialet #ExpertPro
Hackers will appreciate this so read on… 🧵 (1/9)