So testing on my main (non-pi) machine. I'm not seeing the hung sockets (that may have just been an artifact of the pi's lame-o networking), but the memory leak is definitely there and turns on or off depending on the auto sync with server setting. The memory leak seems to increase by (more or less) the size of the file played; every file played increases the memory usage by roughly its size. There's also the slow leak over time too even at idle. One odd thing I noticed which may or may not be a clue: when I tried toggling auto-sync with server from on to off during playback I saw really odd behavior. The currently playing song kept playing, but the stop button wouldn't stop it (even though the MC UI showed the song as stopped). Playing another song resulted in both playing at once and the UI successfully controlled playback for the second song only. Weird.
Here's a diff of the lsofs in the two states during playback (autosync on is the first argument to diff, autosync off is the second argument to diff):
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
< mediacent 10278 michael DEL REG 0,5 111650 /memfd:pulseaudio
---
> mediacent 10278 michael DEL REG 0,5 110720 /memfd:pulseaudio
7c7
< mediacent 10278 michael DEL REG 0,5 57022 /memfd:pulseaudio
---
> mediacent 10278 michael DEL REG 0,5 108267 /memfd:pulseaudio
139c139
< mediacent 10278 michael 19u IPv4 109974 0t0 TCP *:52199 (LISTEN)
---
> mediacent 10278 michael 19u IPv4 57139 0t0 TCP *:52199 (LISTEN)
140a141
> mediacent 10278 michael 21u IPv4 110672 0t0 TCP Neptunian:52199->living_room.system:57196 (ESTABLISHED)
142d142
< mediacent 10278 michael 23u REG 259,6 23664205 3145755 /home/michael/.jriver/Media Center 23/Temp/BufferedInternetReader - 2663028480-0.dat.cnk
143a144
> mediacent 10278 michael 28u REG 259,6 18722850 3145755 /home/michael/.jriver/Media Center 23/Temp/BufferedInternetReader - 3437180672-0.dat.cnk
147,151c148,152
< mediacent 10278 michael 32r REG 259,6 23664205 3145755 /home/michael/.jriver/Media Center 23/Temp/BufferedInternetReader - 2663028480-0.dat.cnk
< mediacent 10278 michael 33r FIFO 0,12 0t0 57019 pipe
< mediacent 10278 michael 34w FIFO 0,12 0t0 57019 pipe
< mediacent 10278 michael 35r FIFO 0,12 0t0 57020 pipe
< mediacent 10278 michael 36w FIFO 0,12 0t0 57020 pipe
---
> mediacent 10278 michael 32r REG 259,6 18722850 3145755 /home/michael/.jriver/Media Center 23/Temp/BufferedInternetReader - 3437180672-0.dat.cnk
> mediacent 10278 michael 33r FIFO 0,12 0t0 108264 pipe
> mediacent 10278 michael 34w FIFO 0,12 0t0 108264 pipe
> mediacent 10278 michael 35r FIFO 0,12 0t0 108265 pipe
> mediacent 10278 michael 36w FIFO 0,12 0t0 108265 pipe
153c154
< mediacent 10278 michael 38u unix 0x00000000926fb9fb 0t0 57023 type=STREAM
---
> mediacent 10278 michael 38u unix 0x00000000ba652056 0t0 108268 type=STREAM
Of note: turning auto-sync off stops the growth in memory usage, but does not release any memory previously built up with auto-sync on, and I took the lsof of auto-sync off after auto-sync on, so the total memory usage was larger than when I took the auto-sync on lsof snapshot. Let me know if I can provide any other useful info (or clean lsofs right after opening MC or something).