On 29.01.2018 19:19, Georg Chini wrote:
On 29.01.2018 18:46, Nico wrote:
On 01/29/2018 03:52 PM, NicoHood wrote:
On 01/29/2018 03:29 PM, Georg Chini wrote:
On 29.01.2018 14:44, NicoHood wrote:
On 01/29/2018 01:39 PM, Georg Chini wrote:
On 29.01.2018 12:52, Nico wrote:
Hi,
I want to capture the audio stream of my TV with my PCI-E
Toslink sound
card and play it back on my usb XLR soundcard. The reason why I
do that
is to use my own music boxes rather than the TV speakers. With
toslink +
XLR I do not have problems with ground loops etc.
I am using the pulseaudio loopback module with its default
configuration. The problem is, that the delay between picture
and sound
is about one second off, and the longer I wait, the more delay
it gets
(30 seconds and more). It is no usable like this.
I tried to play with the latencies of source, sink and the tv delay
itself without sucess. I also tried streaming with pacat
directly as
described here:
https://thelinuxexperiment.com/fix-pulseaudio-loopback-delay/
I also tried to change different parameters of the loopback
module or
the sources/sinks, but that did not help. I never changed any
global
pulseaudio config to avoid larger configuration issues. The CPU
usage of
pulseaudio is at 3% with the loopback module
Can anyone help me to get rid of this lag?
Hi Nico,
which version of PA are you using? Can you provide logs?
Regards
Georg
Hi Georg,
oh sure I completely forgot:
pulseaudio 11.1-1 (Arch Linux)
uname -a: Linux zebes 4.14.15-1-ARCH #1 SMP PREEMPT Tue Jan 23
21:49:25
UTC 2018 x86_64 GNU/Linux
Here is a logfile:
LANG=C pulseaudio -vvvv --log-time=1 > ~/pulseverbose.log 2>&1
https://gist.github.com/NicoHood/85976f426e1621e599253ee1a95230dd
Regards
Nico
This is weird. It looks like the source sample rate is so much higher
than the sink rate that module-loopback can't adapt. No idea why
this happens. Does it work with another input?
I've tested it also with the builtin front microphone input (2nd
revision on gist) and with the PCIE Analog line in (3rd gist revision).
You can view the changes here:
https://gist.github.com/NicoHood/85976f426e1621e599253ee1a95230dd/revisions
The problem only occurs with the digital, optical TOSLINK input from my
Samsung TV. For some other reason the sound distortion for the analog
input is now (temporary) gone. However I still want to get that TOSLINK
running :/
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As an additional test I send the audio to the TOSLINK output of the
soundcard, back to its input and setup loopback on the input again (to
the USB soundcard). With this method the sound has no lag. The
difference is that the toslink signal comes from the soundcard itself
rather than the TV. I have some smaller noises/distortion however
sometimes. Here is the log:
https://gist.github.com/NicoHood/6ef237649d97eaa69d9a78dd91eff34a
Somehow this still sounds like a sample rate mismatch. (A wild
guess, I do not know how the signal chain works for a TOS-link)
Have you tried setting your card to 48kHz? You can change
default-sample-rate and alternate-sample-rate in daemon.conf
both to 48000 and restart pulse to enforce this.
I took a look at your first log again. At some point, module-loopback runs
at 44540 Hz output rate. Log entries are spaced by 10 seconds. Every
10 seconds, the latency increases by 783 ms. When you calculate
(48000 - 44540) *10 / 44100 you get 784 ms, so it is very probable that
you are in fact receiving data at 48kHz.
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