Error after enable loopback

[Aramefarpado]

Dears,

After enable Loopback on Alsa options I can't play anything anymore, I get the error:

ERROR: Failed to open "ALSA Default" (alsa); Error opening ALSA device "_audioout"; snd_pcm_hw_params_set_buffer_time_near() failed: Invalid argument

Disabling Loopback everything works normally again

Code:

pi@moode:~ $ moodeutl -l
20221104 174154 worker: --
20221104 174154 worker: -- Start moOde 8 series
20221104 174154 worker: --
20221104 174154 worker: Successfully daemonized
20221104 174159 worker: File check (OK)
20221104 174200 worker: Session vacuumed
20221104 174200 worker: Session loaded
20221104 174200 worker: Debug logging (OFF)
20221104 174200 worker: --
20221104 174200 worker: -- Audio debug
20221104 174200 worker: --
20221104 174200 worker: ALSA cards: (0:b1 | 1:Headphones | 2:empty | 3:empty
20221104 174200 worker: MPD config: (1:Pi Headphone jack | mixer:(Headphone) | card:1)
20221104 174201 worker: ALSA mixer actual (Headphone)
20221104 174201 worker: ALSA Headphone volume set to (0%)
20221104 174201 worker: --
20221104 174201 worker: -- System
20221104 174201 worker: --
20221104 174204 worker: Host      (moode)
20221104 174204 worker: moOde     (8.2.2 2022-10-23)
20221104 174204 worker: RaspiOS   (11.5)
20221104 174204 worker: Kernel    (5.15.61-v7+ #1579)
20221104 174204 worker: Platform  (Pi-2B 1.1 1GB)
20221104 174204 worker: ARM arch  (armv7l, 32-bit)
20221104 174204 worker: MPD ver   (0.23.5)
20221104 174204 worker: CPU gov   (ondemand)
20221104 174204 worker: USB boot  (not available)
20221104 174204 worker: File sys  (expanded)
20221104 174204 worker: HDMI port (On)
20221104 174204 worker: Sys LED0  (On)
20221104 174204 worker: Sys LED1  (On)
20221104 174204 worker: --
20221104 174204 worker: -- Network
20221104 174204 worker: --
20221104 174204 worker: eth0 adapter exists
20221104 174204 worker: eth0 check for address (No)
20221104 174205 worker: IP addr (192.168.1.8)
20221104 174205 worker: Netmask (255.255.255.0)
20221104 174205 worker: Gateway (192.168.1.1)
20221104 174205 worker: Pri DNS (8.8.8.8)
20221104 174205 worker: Domain  ()
20221104 174205 worker: wlan0 adapter does not exist
20221104 174205 worker: apd0 router mode (Off)
20221104 174205 worker: --
20221104 174205 worker: -- Software update
20221104 174205 worker: --
20221104 174205 worker: Automatic check (Off)
20221104 174205 worker: --
20221104 174205 worker: -- Audio config
20221104 174205 worker: --
20221104 174206 worker: MPD conf updated
20221104 174206 worker: ALSA card number (1)
20221104 174206 worker: MPD audio output (Pi Headphone jack)
20221104 174206 worker: Audio formats (U8, S16_LE)
20221104 174207 worker: ALSA mixer name (Headphone)
20221104 174207 worker: MPD mixer type (software)
20221104 174207 worker: Hdwr volume controller exists
20221104 174207 worker: Max ALSA volume (100%)
20221104 174207 worker: ALSA output mode (Default: plughw)
20221104 174207 worker: ALSA loopback (On)
20221104 174207 worker: Reset renderer active flags
20221104 174207 worker: CamillaDSP (off)
20221104 174207 worker: --
20221104 174207 worker: -- File sharing
20221104 174207 worker: --
20221104 174207 worker: SMB file sharing (Off)
20221104 174207 worker: NFS file sharing (Off)
20221104 174207 worker: --
20221104 174207 worker: -- MPD startup
20221104 174207 worker: --
20221104 174208 worker: MPD started
20221104 174208 worker: MPD accepting connections
20221104 174208 worker: MPD output 1 ALSA Default (On)
20221104 174208 worker: MPD output 2 ALSA Bluetooth (Off)
20221104 174208 worker: MPD output 3 HTTP Server (Off)
20221104 174208 worker: MPD crossfade (off)
20221104 174208 worker: MPD ignore CUE files (yes)
20221104 174208 worker: --
20221104 174208 worker: -- Music sources
20221104 174208 worker: --
20221104 174208 worker: USB sources
20221104 174209 worker: No drives found
20221104 174209 worker: NAS sources
20221104 174209 worker: Music
20221104 174209 worker: Music
20221104 174209 worker: Mount all submitted
20221104 174209 worker: --
20221104 174209 worker: -- Feature availability
20221104 174209 worker: --
20221104 174209 worker: Source select (available)
20221104 174209 worker: Source select (source: MPD)
20221104 174209 worker: Source select (output: Pi Headphone jack)
20221104 174209 worker: Bluetooth (available)
20221104 174210 worker: AirPlay renderer (available: started)
20221104 174210 worker: Spotify renderer (available)
20221104 174210 worker: Squeezelite (available)
20221104 174210 worker: RoonBridge renderer (not installed)
20221104 174210 worker: Multiroom sender (available)
20221104 174210 worker: Multiroom receiver (available)
20221104 174210 worker: UPnP renderer (available: started)
20221104 174210 worker: DLNA server (available: started)
20221104 174210 worker: GPIO button handler (available)
20221104 174210 worker: Stream recorder (n/a)
20221104 174210 worker: --
20221104 174210 worker: -- Other
20221104 174210 worker: --
20221104 174210 worker: USB volume knob (Off)
20221104 174210 worker: USB auto-mounter (udisks-glue)
20221104 174210 worker: Saved MPD vol level (0)
20221104 174210 worker: Preamp volume level (0)
20221104 174211 worker: MPD volume level (45) restored
20221104 174211 worker: ALSA Headphone volume (100%)
20221104 174211 worker: Auto-play (Off)
20221104 174211 worker: LocalUI started
20221104 174211 worker: CoverView toggle (-off)
20221104 174211 worker: On-screen keyboard (Off)
20221104 174211 worker: Library scope (all)
20221104 174211 worker: Maintenance interval (360 minutes)
20221104 174211 worker: Screen saver activation (Never)
20221104 174211 worker: Session permissions (OK)
20221104 174211 worker: Mount monitor (Off)
20221104 174212 worker: Watchdog started
20221104 174212 worker: Ready
20221104 174445 worker: Job mpdcfg
20221104 174449 worker: Job mpdcfg: devchg|mixchg (0|0), alsavol (80%), playstate (paused)
20221104 174510 worker: Job alsa_loopback
20221104 181349 worker: Job alsa_loopback
pi@moode:~ $ mpc play
Carpenters - Please Mister Postman
[paused]  #29/31   0:00/2:53 (0%)
volume: 40%   repeat: off   random: on    single: off   consume: on
ERROR: Failed to open "ALSA Default" (alsa); Error opening ALSA device "_audioout"; snd_pcm_hw_params_set_buffer_time_near() failed: Invalid argument

[Tim Curtis]

I've observed that the integrated audio outputs (HDMI and Headphone) + Loopback need to have sample rate > 44.1K otherwise that error occurs. I'll update the help for upcoming release 8.2.3.

In MPD SoX Resampling section set the Rate to > 44.1K and optionally use Selective resampling to upsample only 44.1K rate leaving other rates as-is.

Note that if Multiroom sender is on, this doesn't apply and any rate will work because ALSA is going to resample to 48K for the Opus CODEC used by the sender.

[Aramefarpado]

worked like a charm
thanks!