[PlanetCCRMA] Installing Google Voice Chat for Linux on Fedora instead of Debian

Niels Mayer nielsmayer at gmail.com
Tue Aug 31 18:07:10 PDT 2010

Now that I've discovered the way of setting hardware devices in
http://mail.google.com/mail/#settings/chat , there's issues that limit
my using GoogleTalkPlugin to "[Logitech USB Headset]" -- a USB headset
that works well.


(1) I have an old Hauppauge PVR-500  dual analog TV card and
/opt/google/talkplugin/GoogleTalkPlugin thinks it's a video camera for
chatting. However, the PVR-500 doesn't work w/ Google Talk, causing
people to attempt to contact by video, but then failing due to this
video device. (However, I could hook up an external old camcorder that
outputs composite or svideo to the PVR500 and it would nicely hardware
mpeg-encode the signal for me, however GoogleTalkPlugin doesn't seem
to recognize any of the output formats.)

There doesn't seem to be a way of telling it not to use a video camera
because i don't have one on this computer.

(2) Attempting to connect a variety of soundcards for input and
output, I found that many, including motherboard soundcards and
built-in snd-hda-intel hardware cannot talk to the GoogleTalkPlugin.
The following errors are issued for output:

(a) sample format mismatch (seen on Terratec DMX6Fire and M-Audio Delta 66).

ALSA lib pcm.c:7320:(snd_pcm_set_params) Sample format not available
for PLAYBACK: Invalid argument
ALSA lib pcm.c:7320:(snd_pcm_set_params) Sample format not available
for CAPTURE: Invalid argument

(above occurs talking to an envy24/ice1712's analog capture or pcm
outs. ... this error doesn't occur talking to the cards's 2-channels
of spdif output, or capturing from the spdif input. For the output
case, the spdif output can be sent to the card's built-in digital
mixer, which can then be routed (via http://mudita24.googlecode.com or
envy24control(1)) to the appropriate analog output for listening on
headphones and works correctly with GoogleVoicePlugin...
unfortunately, w/o a hardware spdif loopback this hack doesn't work
for using the card's microphone input).

(b) Channel count mismatch on Playback with totally standard output
devices, both motherboard and USB:

ALSA lib pcm.c:7326:(snd_pcm_set_params) Channels count (1) not
available for PLAYBACK: Invalid argument

(this seems to happen with some USB stereo soundcards and the
motherboard  via snd-hda-intel audio hardware, when connecting to
"front" device.)

Note that these audio issues would probably not occur if I was running
pulseaudio, however, it is a mistake for Google to assume that
everybody in Linuxland uses pulseaudio. (And even if pulseaudio were
running, there'd be similar problems talking to multichannel
soundcards such as the M-audio delta series).

It sure would be nice to use the Terratec Dmx6Fire's handy microphone
input with a sensitivity knob, overload-LED, etc, and built-in digital
mixer, hardware-metering, and full control via
working properly, as it's nice being able to have proper microphone
metering, and full mixer control for audio input/output... However,
the current limitations seem to make that difficult.

Perhaps my earlier "wrappering" approach and setting up a separate
ALSA environment for google talk was the right way after all, at least
for such "prosumer" soundcards. That way I could use plughw to match
bit depths on PCM output; I'd have to figure out how to do that on

How exactly could one work around
"ALSA lib pcm.c:7320:(snd_pcm_set_params) Sample format not available
for CAPTURE: Invalid argument"
for capture inputs? Is there anything like plughw that works for capture too?

-- Niels.

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