I can not control the latency in module-loopback
Submitted by Alessandro Ferri
Assigned to pul..@..op.org
Description
I would like to minimize the latency time between the audio input from the Cirrus Logic Audio Card (for raspberry Pi2) and the audio output over bluetooth speaker. I note an important time separation between my input voice on the output on Bluetooth and I would like to minimize this time. I tried to control the latency with the command:
pactl load-module module-loopback latency_msec=1 source="alsa_input.platform-sound.analog-stereo" sink="bluez_sink.B8_27_EB_00_82_2D"
or
pacat -r --latency=102800 -d alsa_input.platform-sound.analog-stereo | pacat -p --latency=102800 -d bluez_sink.B8_27_EB_00_82_2D
but it seems that the options are ignored. Below my sink and reference source:
Sink #2 State: SUSPENDED Name: bluez_sink.B8_27_EB_00_82_2D Description: BlueAni-00822d Driver: module-bluez5-device.c Sample Specification: s16le 2ch 44100Hz Channel Map: front-left,front-right Owner Module: 15 Mute: no Volume: front-left: 65536 / 100% / 0.00 dB, front-right: 65536 / 100% / 0.00 dB balance 0.00 Base Volume: 65536 / 100% / 0.00 dB Monitor Source: bluez_sink.B8_27_EB_00_82_2D.monitor Latency: 0 usec, configured 0 usec Flags: HARDWARE DECIBEL_VOLUME LATENCY Properties: bluetooth.protocol = "a2dp_sink" device.description = "BlueAni-00822d" device.string = "B8:27:EB:00:82:2D" device.api = "bluez" device.class = "sound" device.bus = "bluetooth" bluez.path = "/org/bluez/hci0/dev_B8_27_EB_00_82_2D" bluez.class = "0x0c0000" bluez.alias = "BlueAni-00822d" device.icon_name = "audio-card-bluetooth" Ports: unknown-output: Bluetooth Output (priority: 0) Active Port: unknown-output Formats: pcm
Source #1 State: SUSPENDED Name: alsa_input.platform-sound.analog-stereo Description: snd_rpi_wsp Analog Stereo Driver: module-alsa-card.c Sample Specification: s16le 2ch 44100Hz Channel Map: front-left,front-right Owner Module: 1 Mute: no Volume: front-left: 65536 / 100% / 0.00 dB, front-right: 65536 / 100% / 0.00 dB balance 0.00 Base Volume: 65536 / 100% / 0.00 dB Monitor of Sink: n/a Latency: 0 usec, configured 0 usec Flags: HARDWARE DECIBEL_VOLUME LATENCY Properties: alsa.resolution_bits = "16" device.api = "alsa" device.class = "sound" alsa.class = "generic" alsa.subclass = "generic-mix" alsa.name = "" alsa.id = "WM5102 AiFi wm5102-aif1-0" alsa.subdevice = "0" alsa.subdevice_name = "subdevice #0" alsa.device = "0" alsa.card = "1" alsa.card_name = "snd_rpi_wsp" alsa.long_card_name = "snd_rpi_wsp" alsa.driver_name = "snd_soc_rpi_wsp" device.bus_path = "platform-sound" sysfs.path = "/devices/platform/sound/sound/card1" device.string = "hw:1" device.buffering.buffer_size = "352800" device.buffering.fragment_size = "58800" device.access_mode = "mmap+timer" device.profile.name = "analog-stereo" device.profile.description = "Analog Stereo" device.description = "snd_rpi_wsp Analog Stereo" module-udev-detect.discovered = "1" device.icon_name = "audio-card" Ports: analog-input: Analog Input (priority: 10000) Active Port: analog-input Formats: pcm
I take it for granted that the bluetooth latency output is already at zero, How can I control this latency.