[pulseaudio-discuss] Pulseaudio latency

Tue Jul 31 05:10:15 UTC 2018

Hi Georg,

As i told module-loopback is giving overall latency around 300ms from the
time when i started the sequence, and *latency of module-loopback doesn't
grow at any point of time*. On saturday and sunday, we have kept a
continuous streaming for 2 days, expecting that the delay will be further
increased, but the delay is constant with 4-5 secs, and *there are no
errors in the logs*. Are there any chances like alsa-sink is filling
somewhere and blocking the source to send the audio chunks into the
memblockq?

*module-loopback output is like this:*
*Tue Jul 31 10:15:37 2018 user.debug pulseaudio[4370]: (47917.422|   0.020)
[alsa-sink-I2S cx2072x-dsp-0] alsa-sink.c: Wakeup from ALSA!*
*Tue Jul 31 10:15:37 2018 user.debug pulseaudio[4370]: (47917.443|   0.020)
[pulseaudio] module-loopback.c: Loopback overall latency is 0.02 ms +
244.43 ms + 54.55 ms = 298.89 ms*
*Tue Jul 31 10:15:37 2018 user.debug pulseaudio[4370]: (47917.443|   0.000)
[pulseaudio] module-loopback.c: Loopback latency at base rate is 298.42 ms*
*Tue Jul 31 10:15:37 2018 user.debug pulseaudio[4370]: (47917.443|   0.000)
[pulseaudio] module-loopback.c: [alsa_output.0] Updated sampling rate to
44053 Hz.*

*pactl list sources:*
*Source #1*
* State: RUNNING*
* Name: bluez_source*
* Description: AP 🙏*
* Driver: module-bluez5-device.c*
* Sample Specification: s16le 2ch 44100Hz*
* Channel Map: front-left,front-right*
* Owner Module: 17*
* 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: 45876 usec, configured 39512 usec*
* Flags: HARDWARE DECIBEL_VOLUME LATENCY *
* Properties:*
* bluetooth.protocol = "a2dp_source"*
* device.description = "AP 🙏"*
* device.string = "AC:C1:EE:69:A6:02"*
* device.api = "bluez"*
* device.class = "sound"*
* device.bus = "bluetooth"*
* device.form_factor = "phone"*
* bluez.path = "/org/bluez/hci0/dev_AC_C1_EE_69_A6_02"*
* bluez.class = "0x5a020c"*
* bluez.alias = "AP 🙏"*
* device.icon_name = "audio-card-bluetooth"*
* Ports:*
* phone-input: Phone (priority: 0, available)*
* Active Port: phone-input*
* Formats:*
* pcm*

*pactl list sinks:*
*Sink #0*
* State: RUNNING*
* Name: alsa_output.0*
* Description: ipq4019_snd_card*
* Driver: module-alsa-sink.c*
* Sample Specification: s16le 2ch 48000Hz*
* Channel Map: front-left,front-right*
* Owner Module: 5*
* 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: alsa_output.0.monitor*
* Latency: 0 usec, configured 26000 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 <http://alsa.name> = ""*
* alsa.id <http://alsa.id> = "I2S cx2072x-dsp-0"*
* alsa.subdevice = "0"*
* alsa.subdevice_name = "subdevice #0"*
* alsa.device = "0"*
* alsa.card = "0"*
* alsa.card_name = "snd_card"*
* alsa.long_card_name = "snd_card"*
* alsa.driver_name = "snd_card"*
* device.string = "dmixer"*
* device.buffering.buffer_size = "383040"*
* device.buffering.fragment_size = "4032"*
* device.access_mode = "mmap+timer"*
* device.description = "snd_card"*
* device.icon_name = "audio-card"*
* Formats:*
* pcm*

On Sun, Jul 29, 2018 at 9:37 PM Georg Chini <georg at chini.tk> wrote:

> On 29.07.2018 18:03, Georg Chini wrote:
>
> On 29.07.2018 12:44, Harish Gaddameedi wrote:
>
> Hi Georg,
>
> I was working on simple Openwrt Platform, and Source device is Android
> phone Bluetooth with Youtube app 24 hrs live streaming video and alsa
> device is speaker, which is hardwired
>
> The 12 hrs testing which i did on pulseaudio-11.1 are without my
> modification. The basic modification which i made in the previous
> pulseaudio-8.0 is with the idle state of bluez_source card (i.e., card is
> vanishing when the song is in the pause state) and did some changes to
> buffers of pulseaudio to reduce the latency. But in pulseaudio-11.1 i
> didn't do all the changes as i didn't find any initial latency. but
> periodic latency after 12hrs still exists. The issue is reproducible with
> Gstreamer also.
>
> I haven't worked on microphone scenarios, I'm just working on music player
> and speaker.
>
> Let me clear you some test scenarios for better understanding,
> Case 1: Android phone as source (bluez_source) and device with internal
> speaker (alsa-sink as sink for pulseaudio) -------> delay after 12hrs
> exists.
> Case 2: Device with Gstreamer as source and same device with internal
> speaker (pulsesink with alsa card as sink for pulseaudio) ---------->
> delay after 12 hrs exists.
> Case 3: Device with Gstreamer as source and External Bluetooth speaker
> (pulsesink with bluez_sink card) -----------> No delay after 12 hrs.
>
> What output does module-loopback give when you run with debugging?
> Do you see the growing latency there? Does it show up with pactl list sinks
> or pactl list sources? Any error messages in the PA log?
>
> Regards
>              Georg
>
> One more comment: It may well be worth trying 12.2 because the bluetooth
> thread
> function has changed.
>

-- 
Regards,
Harish Gaddameedi
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