Hi Cristian,
On Sun, Aug 28, 2016 at 12:50:59PM +0200, Cristian Ionescu-Idbohrn wrote:
> On Sun, 28 Aug 2016, Muammar El Khatib wrote:
> >
> > That was the idea. After your report, I realized mkchromecast is
> > mostly useless in systems without pulseaudio right now. I will
> > remove that dependency in next releases.
>
> Great.
>
> > Yesterday, I was already playing with ffmpeg + ALSA to capture
> > audio, but I think it will be a complicated solution to implement
> > (cards' and devices' names may change from system to system). I had
> > forgotten about GStreamer completely. Reading just a bit about it,
> > it may be a possible solution.
>
> Nice.
>
> I'll be watching this space and be ready to test mkchromecast again
> whenever possible.
Would you mind testing if this procedure makes possible to record your audio
using alsa?
1. Do
modprobe snd-aloop
2. Add the following content to ~/.asoundrc
pcm.!default {
type asym
playback.pcm "LoopAndReal"
#capture.pcm "looprec"
capture.pcm "hw:0,0"
}
pcm.looprec {
type hw
card "Loopback"
device 1
subdevice 0
}
pcm.LoopAndReal {
type plug
slave.pcm mdev
route_policy "duplicate"
}
pcm.mdev {
type multi
slaves.a.pcm pcm.MixReale
slaves.a.channels 2
slaves.b.pcm pcm.MixLoopback
slaves.b.channels 2
bindings.0.slave a
bindings.0.channel 0
bindings.1.slave a
bindings.1.channel 1
bindings.2.slave b
bindings.2.channel 0
bindings.3.slave b
bindings.3.channel 1
}
pcm.MixReale {
type dmix
ipc_key 1024
slave {
pcm "hw:0,0"
rate 48000
#rate 44100
periods 128
period_time 0
period_size 1024 # must be power of 2
buffer_size 8192
}
}
pcm.MixLoopback {
type dmix
ipc_key 1025
slave {
pcm "hw:Loopback,0,0"
rate 48000
#rate 44100
periods 128
period_time 0
period_size 1024 # must be power of 2
buffer_size 8192
}
}
3. Install ffmpeg, and execute this command while playing anything in your
computer:
ffmpeg -f alsa -ac 2 -ar 44100 -i hw:0 -t 30 out.wav
Does ffmpeg capture the audio in out.wav?. I tested this in a Virtualbox using
debian with pure alsa (I was lazy, and didn't reconfigure everything in my own
laptop). I think the procedure above did the trick but sound was crippled
(maybe related to Virtualbox).
Thanks.
--
Muammar El Khatib.
Linux user: 403107.
GPG Key = 71246E4A.
http://muammar.me | http://proyectociencia.org
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