[MPlayer-users] Playing from v4l NOVIRUS

Todd Lyons TLyons at sequentusa.com
Sat Nov 8 01:47:20 CET 2003


> >> I'm trying to play and later archive video/sound 
> >>from a v4l device.  The driver (bttv and btaudio) are both 
> >>successfully loaded, see below for dmesg output.  Video displays 
> >>properly with no problems.  But no sound is played. Am I mistaken in 
> >>thinking that I can have mplayer grab video/audio (physical devices 
> >>video0 and dsp1) from the capture card and play the video 
> >> back on the screen with audio out through /dev/dsp (my 
> >> regular sound chip)?
> I think mplayer only initialize (unmute) audio-out of tv 
> card. You can 

Good, you understand my question exactly.

> watch tv with sound when the audio-out of tv card and 
> audio-in (line-in, 
> aux, cd-in) of sound card are connected. Mplayer is not able to route 
> audio (am I wrong?). When you choose adevice=/dev/dsp2 you 
> choose it as 
> audio-out.

So I guess what I'm asking for is to be able to specify both the audio input
device and the audio output device, even though they are on different cards.
I have to ask the obvious question:  What's the use of saying "use a v4l
device" if I directly specify the audio devices?  That makes it seem like my
request is useless.

I want to somehow say:
  audio_input=v4l audio_output=alsa
Hopefully I'll figure out a way to do this by massaging the commandline.

It may also be that I simply cannot do this with mplayer (as you suggest it
cannot route output to a different chipset than the input is being grabbed
from).  I may have to encode and then play back the file as two separate
processes.

> To use btaudio module you should conneect some amplifier directly to 
> your Osprey - then you should have to configure it such as second sound 
> card (I never tried it then I do not know how) - check your sound mixer 
> for second panel?
> >>btaudio: registered device dsp1 [digital]
> >>btaudio: registered device dsp2 [analog]

I've only been using aumix because in my experience, kmix hasn't worked well
for me.  I think it's normal that aumix only sees one sound card, though it
does have a "Video" input slider and it is stereo since I have a balance
control too.  I'll try aumix without loading the bttv and btaudio modules to
see if that "Video" control is present.  I will also try kmix again and see
if it sees a second card.

Regards...			Todd



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