[Jack-Devel] Firefox HTML5 native audio and alsa jack-plugin (was Re: Flash Support)

Am 05.11.2013 23:37, schrieb Uwe Koloska:
> So I opted for the jack-plugin and found it working most of the time (or
> better all times minus one).  The one exception is native web audio in
> firefox 25 (chromium and opera are just fine -- BTW opera seems to have
> native jack support!).  If I remember correctly, FF 24 has worked, too.
>  And flash audio still works if native audio presents silence -- how
> embarrassing!

I have found a bug report for mozilla firefox:
  812900 – No sound in html5 with jack on archlinux
  https://bugzilla.mozilla.org/show_bug.cgi?id=812900

Unfortunately all workarounds given in the thread don't work in the
current version of firefox.

The reason for the problem is missing support for FLOAT_LE in the jack
plugin chain.  With jack-plugin slaved on default

  aplay -v -c 2 -r 44100 -f FLOAT_LE /dev/zero

doesnt't work -- while this does

  aplay -v -c 2 -r 44100 -f S16_LE /dev/zero

and what I now figured out while trying to document the behaviour for
this list:

  aplay -v -c 2 -r 48000 -f FLOAT_LE /dev/zero

is working, too!

So it's not the format but the rate.  The running aplay with S16_LE has
the following conversion chain running:

-----------------------------------------------------------------
Plug PCM: Rate conversion PCM (48000, sformat=S16_LE)
Converter: libspeex (builtin)

Slave: Linear Integer <-> Linear Float conversion PCM (FLOAT_LE)

Slave: ALSA <-> JACK PCM I/O Plugin
-----------------------------------------------------------------

Maybe the samplerate converter can't cope with FLOAT_LE?

With jack configured for 44100 the FLOAT_LE aplay ist working but not so
firefox HTML5 audio (flash works all the time). There now is a jack
client but I cannot connect it (in qjackctl) and the audio has a long
waiting time (approx. 10s) at the beginning -- and still no sound when
it seems to play.

One more experiment: With
  defaults.pcm.rate_converter "samplerate"
it doesn't work (both: aplay and firefox) :-(

Greetings
Uwe

1383785626.706_0.ltw:2,a <527AE493.2060107 at koloro dot de>