Re: [gentoo-user] sound stuttering, breaking up, fading in and out

[Fernando Rodriguez]

On Saturday, April 18, 2015 6:46:37 PM Chris Spackman wrote:
> I have an issue with sound during music and sometimes video
> playback. Usually it fades out (gets quieter) and then fades back in a
> couple of seconds later. This happens randomly maybe a couple of times
> in an hour or two, but can sometimes go several hours without
> issue. It has happened with quodlibet and mocp (audio - mostly ogg,
> some mp3) and with vlc (video - mostly mp4/m4v). I don't use other
> music/video software enough to notice it there.
>
> During heavy load (like emerging packages), the sound will sometimes
> stutter or even stop and then restart a few seconds later. The
> computer is a few years old, but this has not happened in the past.
>
> I found somewhere the suggestion to add the following options to
> /etc/modprobe.d/sound.conf
>
> options snd-hda-intel vid=8086 pid=8ca0 snoop=0
>
> The fading out/in *seems to be* less frequent since doing that. But
> that is my subjective feeling, not based on data.
>
> Any ideas on what might be wrong and how it can be fixed?
>
> ** System **
>
> Window Manager = PekWM
>
> kernel = Linux sys76 3.18.11-gentoo #1 SMP PREEMPT Thu Apr 9 13:56:02 EDT
2015 x86_64 Intel(R) Core(TM)2 Quad CPU Q8400 @ 2.66GHz GenuineIntel GNU/Linux
>
>
> ** Hardware Info **
>
> lspci reports:
> Audio device: Intel Corporation 82801JI (ICH10 Family) HD Audio Controller
>
> Modules, from lsmod | grep snd:
>
> snd_hda_codec_idt      39744  1
> snd_hda_codec_generic    39746  1 snd_hda_codec_idt
> snd_hda_intel          17007  2
> snd_hda_controller     13712  1 snd_hda_intel
> snd_hda_codec          68033  4
> snd_hda_codec_idt,snd_hda_codec_generic,snd_hda_intel,snd_hda_controller
> snd_hwdep               5373  1 snd_hda_codec
> snd_pcm                63521  3
> snd_hda_codec,snd_hda_intel,snd_hda_controller
> snd_timer              15422  1 snd_pcm
> snd                    49995  11
snd_hwdep,snd_timer,snd_hda_codec_idt,snd_pcm,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel
>
> ** Software **
>
> [I] media-sound/pulseaudio
>
>           Installed versions:  5.0-r7(03:35:44 PM 04/08/2015)(X alsa
>      alsa-plugin asyncns bluetooth caps dbus gdbm glib gtk ipv6 orc
>      qt4 ssl tcpd udev webrtc-aec -doc -equalizer -gnome -jack
>      -libsamplerate -lirc -neon -oss -realtime -system-wide -systemd
>      -test -xen -zeroconf ABI_MIPS="-n32 -n64 -o32" ABI_PPC="-32 -64"
>      ABI_S390="-32 -64" ABI_X86="64 -32 -x32")
>
> [I] media-plugins/gst-plugins-pulse
>
>           Installed versions:  0.10.31-r1(0.10)^t(12:55:06 PM
>      04/11/2015)(ABI_MIPS="-n32 -n64 -o32" ABI_PPC="-32 -64"
>      ABI_S390="-32 -64" ABI_X86="64 -32 -x32") 1.4.5(1.0)^t(04:27:00
>      PM 04/05/2015)(ABI_MIPS="-n32 -n64 -o32" ABI_PPC="-32 -64"
>      ABI_S390="-32 -64" ABI_X86="64 -32 -x32")
>
> [I] media-sound/moc
>
>           Installed versions:  2.5.0(05:50:51 PM 04/12/2015)(aac alsa
>      cache ffmpeg flac mad magic unicode vorbis -curl -debug -jack
>      -libsamplerate -modplug -musepack -oss -sid -sndfile -speex
>      -timidity -tremor -wavpack)
>
> (I removed Quodlibet recently for unrelated reasons.)
>
> Thanks for any and all help and advice.
>

The Arch wiki has a lot of tips for configure pulseaudio: 
https://wiki.archlinux.org/index.php/PulseAudio/Troubleshooting#Setting_the_default_fragment_number_and_buffer_size_in_PulseAudio
There was another page with tips at freedesktop.org but I can't find it now.

Adjusting the fragment size fixed the choppy sound problem for me. Enabling the 
realtime scheduling may also help (on Gentoo you need to enable the realtime 
flag too) but for me that just seemed to make it more resource hungry.

Also if you haven't enable the pulseaudio flag globally and run emerge -vauDN 
@world and disable all ALSA features on your kernel (except PCI and HD Audio 
drivers) and uninstall the alsa mixer. All together these gave me the best 
results. Sometimes still I start getting choppy audio after large updates and 
when that happens the only way I've been able to fix it is rebooting.

I occassionally have problems with volume, if I lower it sometimes it rases 
itself back up and if I plug in headphones and unplug them sometimes the 
builtin speakers stay muted so I have to plug it back in and out. This only 
happens on one of my laptops and I haven't figured how to fix it.

In short, pulseaudio sucks. But I do find that it gives better audio quality 
than alsa even after tweaking alsa settings and for me it integrates better 
with KDE.

-- 
Fernando Rodriguez