With pulse/pulseaudio, snapclient keeps logging no chunks available and keeps soundcard from suspending.

[nkvoll]

When using snapclient --player pulse, the client logs [Info] (Stream) No chunks available every second. While the logging does not bother me, it seems it also does not release the sound cards, so they're kept in RUNNING state perpetually:

$ pactl list sinks short
0       alsa_output.pci-0000_05_00.0.analog-stereo      module-alsa-card.c      s16le 2ch 48000Hz       RUNNING
1       alsa_output.usb-Creative_Technology_Ltd_Sound_Blaster_Play__3_00237830-00.analog-stereo module-alsa-card.c      s16le 2ch 48000Hz       RUNNING
2       alsa_output.usb-Solid_State_System_Co._Ltd._USB_Gaming_Box_1234567896F3-00.analog-stereo        module-alsa-card.c      s24le 2ch 48000Hz       RUNNING

In a setup where I'm running 4 snapclients I'm also noting that this seems to cause pulseaudio to take roughly 10% CPU (recent AMD Ryzen 5), and each snapclient instance taking around 1%. In my setup, pulseaudio is also doing some remixing, but if I stop the snapclients, its CPU drops to 0%, so it looks like it's processing silence? If this is the case, would it be possible to stop playing / sending sound when the stream they're following is idle?

Steps to Reproduce

1. Start a snapserver with any config
2. Start a snapclient like in the below example
3. Check pactl list sinks short.

Environment

• OS: debian
• Snapcast version 0.25.0 (tested with the latest release and last build from the develop branch.)

Logfile

$ snapclient -h 192.168.2.234 --player pulse --mixer hardware --logfilter debug
2021-10-17 22-36-32.885 [Debug] (Snapclient) Trying to get PCM device for player: pulse, parameter: , card: default
2021-10-17 22-36-32.898 [Info] (Snapclient) Version 0.25.0, revision 4f2f16db
2021-10-17 22-36-32.898 [Info] (Connection) Resolving host IP for: 192.168.2.234
2021-10-17 22-36-32.898 [Info] (Connection) Connecting
2021-10-17 22-36-32.898 [Notice] (Connection) Connected to 192.168.2.234
2021-10-17 22-36-32.898 [Info] (Connection) My MAC: "52:54:00:53:68:47", socket: 8
2021-10-17 22-36-32.921 [Debug] (Connection) outstanding async_write
2021-10-17 22-36-32.922 [Info] (Controller) ServerSettings - buffer: 1000, latency: 0, volume: 100, muted: 0
2021-10-17 22-36-32.922 [Warn] (Connection) Failed to deserialize message of type: StreamTags
2021-10-17 22-36-32.923 [Info] (Controller) Codec: flac, sampleformat: 48000:16:2
2021-10-17 22-36-32.923 [Info] (Player) Player name: pulse, device: default, description: Let PulseAudio server choose the device, idx: 7, sharing mode: unspecified, parameters: <none>
2021-10-17 22-36-32.923 [Info] (Player) Mixer mode: hardware, parameters: <none>
2021-10-17 22-36-32.923 [Info] (Player) Sampleformat: 48000:16:2, stream: 48000:16:2
2021-10-17 22-36-32.923 [Info] (PulsePlayer) Setting property "application.icon_name" to "snapcast"
2021-10-17 22-36-32.923 [Info] (PulsePlayer) Setting property "media.role" to "music"
2021-10-17 22-36-32.923 [Info] (PulsePlayer) Using buffer_time: 100 ms, server: default
2021-10-17 22-36-32.923 [Debug] (PulsePlayer) State changed 2: authorizing
2021-10-17 22-36-32.929 [Debug] (PulsePlayer) State changed 3: setting name
2021-10-17 22-36-32.932 [Debug] (PulsePlayer) State changed 4: ready
2021-10-17 22-36-32.934 [Info] (Stream) outputBufferDacTime > bufferMs: 139692691104 > 1000
2021-10-17 22-36-32.934 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-32.935 [Debug] (PulsePlayer) event_type: 0, facility: 2
2021-10-17 22-36-32.935 [Info] (Stream) No chunks available
2021-10-17 22-36-32.936 [Debug] (PulsePlayer) pa_context_get_sink_info_by_index info: 1, eol: 0
2021-10-17 22-36-32.936 [Debug] (PulsePlayer) Volume changed: 1, muted: 0
2021-10-17 22-36-32.936 [Debug] (PulsePlayer) Last volume change by server: 2 ms => ignoring volume change
2021-10-17 22-36-32.936 [Debug] (PulsePlayer) pa_context_get_sink_info_by_index info: 0, eol: 1
2021-10-17 22-36-32.962 [Info] (Controller) diff to server [ms]: 0.006
2021-10-17 22-36-33.019 [Info] (Stream) No chunks available
2021-10-17 22-36-33.939 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-34.029 [Info] (Stream) No chunks available
2021-10-17 22-36-34.959 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-35.009 [Info] (Stream) No chunks available
2021-10-17 22-36-35.979 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-36.019 [Info] (Stream) No chunks available
2021-10-17 22-36-36.988 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-37.009 [Info] (Stream) No chunks available
2021-10-17 22-36-37.999 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-38.029 [Info] (Stream) No chunks available
2021-10-17 22-36-39.009 [Info] (Stream) No chunks available
2021-10-17 22-36-39.009 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-40.019 [Info] (Stream) No chunks available
2021-10-17 22-36-40.019 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-41.010 [Info] (Stream) No chunks available
2021-10-17 22-36-41.029 [Debug] (Stream) Failed to get chunk, returning silence
2021-10-17 22-36-42.019 [Info] (Stream) No chunks available
2021-10-17 22-36-42.039 [Debug] (Stream) Failed to get chunk, returning silence