USB audio cuts 2-3 secs at start

USB audio cuts 2-3 secs at start

[Stuart Naylor]

http://alsa-project.org/db/?f=6b107178c9939f235a390c07cb5c1f71d6a6e0c0

Its an Anker power conf and for some reason the first couple of seconds of aplay do not play via USB.

Alsa-info above anyone and tips or ideas?


Stuart

Re: USB audio cuts 2-3 secs at start

[Hector Martin 'marcan']

On 29/07/2020 02.08, Stuart Naylor wrote:
> http://alsa-project.org/db/?f=6b107178c9939f235a390c07cb5c1f71d6a6e0c0
> 
> Its an Anker power conf and for some reason the first couple of seconds of aplay do not play via USB.
> 
> Alsa-info above anyone and tips or ideas?

I bet this is just the way the hardware behaves. It probably takes a few 
seconds to turn on its amplifiers and audio path when USB streaming starts.

If it doesn't happen in other OSes, then most likely those OSes 
continuously stream audio to the device even when it is unused. The 
workaround would be to do the same, e.g. use pulseaudio and disable 
suspend-on-idle, or use JACK, or something along those lines that always 
keeps the device running (with silence when no app is using it).

-- 
Hector Martin "marcan" (marcan@marcan.st)
Public Key: https://mrcn.st/pub

RE: USB audio cuts 2-3 secs at start

[Stuart Naylor]

Thanks for the reply.

Windows it works with and a recent firmware fix solved that as its shipped with Windows behaving the same.
The Anker Power conf has a smartphone app that makes the firmware update a button click.
I don’t think they could make a secret update to windows and also I did originally think the same.
I used sox with the -n option to constantly send a null silent stream.
The unit doesn’t seem to like that as received some weird effects with recording.
Its almost like the unit prefers to switch modes and can do so quickly but not both at once.
I guess it operates in a similar manner to wideband Bluetooth as its both USB & Bluetooth but only one connected device and interface can be used at one time.

On X86 and I say X86 as the difference might be Pulseaudio not architecture just my Socs where quick tests with aplay.
I haven’t looked at the asound.conf of Ubuntu desktop but Alsa could be set to use the PA Server.
Again I was using aplay but onX86 Ubuntu only the very first play cuts and all subsequent are then like windows.
I am fairly sure PA doesn’t employ keepalive trickles but maybe it does?

I would of probably agreed with you until my sox hack produced such an array of problems.

Stuart

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: Hector Martin 'marcan'<mailto:marcan@marcan.st>
Sent: 10 August 2020 05:47
To: Stuart Naylor<mailto:stuartiannaylor@outlook.com>; alsa-devel@alsa-project.org<mailto:alsa-devel@alsa-project.org>
Subject: Re: USB audio cuts 2-3 secs at start

On 29/07/2020 02.08, Stuart Naylor wrote:
> http://alsa-project.org/db/?f=6b107178c9939f235a390c07cb5c1f71d6a6e0c0
>
> Its an Anker power conf and for some reason the first couple of seconds of aplay do not play via USB.
>
> Alsa-info above anyone and tips or ideas?

I bet this is just the way the hardware behaves. It probably takes a few
seconds to turn on its amplifiers and audio path when USB streaming starts.

If it doesn't happen in other OSes, then most likely those OSes
continuously stream audio to the device even when it is unused. The
workaround would be to do the same, e.g. use pulseaudio and disable
suspend-on-idle, or use JACK, or something along those lines that always
keeps the device running (with silence when no app is using it).

--
Hector Martin "marcan" (marcan@marcan.st)
Public Key: https://mrcn.st/pub