no sound in firefox youtube videos (HTML5)

[Giuseppe Pagnoni]

Hi all,

I have installed firefox from the ports tree but I cannot get any sound 
from youtube videos (HTML5, so this is not a flash issue).

The configuration for the firefox build is:

===> The following configuration options are available for firefox-42.0,1:
      BUNDLED_CAIRO=off: Use bundled fork of cairo-1.9.5
      CANBERRA=off: Sound theme alerts
      DBUS=on: D-Bus IPC system support
      DEBUG=off: Build with debugging support
      DTRACE=off: Build with DTrace probes
      GCONF=off: GConf configuration backend support
      GIO=on: Use GIO for file I/O
      GNOMEUI=off: libgnomeui support module
      GSTREAMER=on: Multimedia support via GStreamer
      INTEGER_SAMPLES=off: Integer audio sample format
      LIBPROXY=off: Proxy support via libproxy
      OPTIMIZED_CFLAGS=on: Use extra compiler optimizations
      PGO=off: Use Profile-Guided Optimization
      PROFILE=off: Build with profiling support
      TEST=off: Build and/or run tests
====> Options available for the multi AUDIO: you have to choose at least 
one of them
      ALSA=on: ALSA audio architecture support
      PULSEAUDIO=on: PulseAudio sound server support
====> Options available for the single TOOLKIT: you have to select 
exactly one of them
      GTK2=on: GTK+ 2 GUI toolkit support
      GTK3=off: GTK+ 3 GUI toolkit support

and my system is an amd64 10.2-RELEASE.

Note that I can hear the audio fine if I open the same video in chrome.

Thanks in advance for any help, let me know if you need more info

best
giuseppe


-- 
Giuseppe Pagnoni
Dip. Scienze Biomediche, Metaboliche e Neuroscienze
Sezione Fisiologia e Neuroscienze
Univ. di Modena e Reggio Emilia
Via Campi 287
I-41125 Modena, Italy
Tel: +39-059-205-5742
Fax: +39-059-205-5363