.. Jens Getreu
.. v1.1, 29.11.2014

.. excerpt-begin

This manual shows how to record the output of Windows applications using
``wine``, the ``snd-aloop`` kernel module and ``recordMyDesktop``.  [#]_

The ``snd-aloop`` module is very useful when you need to record other
sound sources then your microphone. Simply connect the “noisi”
application to the first sound loopback device provided by
``snd-aloop`` and the screen recorder to the second.

.. [#] Tested with Debian 7 wheezy.
.. excerpt-end


Load the kernel module
======================

By hand (as root)::

    sudo modprobe snd-aloop

Make it reboot persistent::

    sudo echo 'snd-aloop' >> /etc/modules

Check if the module is loaded and initialized::

    aplay -l

    **** List of PLAYBACK Hardware Devices **\**
    card 0: PCH [HDA Intel PCH], device 0: CX20590 Analog [CX20590 Analog]
      Subdevices: 1/1
      Subdevice #0: subdevice #0
    card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
      Subdevices: 1/1
      Subdevice #0: subdevice #0
    card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1]
      Subdevices: 1/1
      Subdevice #0: subdevice #0
    card 0: PCH [HDA Intel PCH], device 8: HDMI 2 [HDMI 2]
      Subdevices: 1/1
      Subdevice #0: subdevice #0
    card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
      Subdevices: 8/8
      Subdevice #0: subdevice #0
      Subdevice #1: subdevice #1
    ...
      Subdevice #7: subdevice #7
    card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
      Subdevices: 8/8
      Subdevice #0: subdevice #0
      Subdevice #1: subdevice #1
    ...
      Subdevice #7: subdevice #7

.. Note::

   | ``snd-aloop`` provides 2 pass-through devices:
   | **card 1, device 0** and
   | **card 1, device 1**.

Redirect your application sound into the first loop-back device
===============================================================

Card 1, device 0
    Input device: redirect the output of the program you want to record
    into this device.

Example ``aplay``
-----------------

::

    aplay -D hw:1,0,0 play.wav

Example ``wine`` application
----------------------------

::

    winecfg

Audio > Output device > Out:Loopback - Loopback PCM (choose first)

|winecfg|

Connect your recorder input to the second loop-back device
==========================================================

Card 1, device 1
    Output device: everything pumped into the first loop-back device
    will be sent out here.

Example ``arecord``
-------------------

Example: ``aplay``

::

    arecord -D hw:1,1,0 record.wav

Example ``RecordMyDesktop``
---------------------------

::

    Device: hw:1,1,0

Advanced > Sound > Device > hw:1,1,0

|RecordMyDesktop|

Complete example: Record a virtual machine using pulse audio
============================================================

1. Install package ``recordmydesktop``

   ::

       sudo apt-get install recordmydesktop

2. Load loopback kernal module

   ::

       sudo modprobe snd-aloop

3. Start virtual machine

4. Redirect output of virtual machine in loop-back device using \_p

   ::

       pavucontrol

   |redirect VM output in loopback device|

   For other examples see: `section\_title <#redirect>`__.

5. Start player in virtual machine

6. Record virtual machine

   ::

       recordmydesktop --device hw:1,1,0 -x 284 -y 42 --width=1349 --h

   Adjust coordinates to your need. You can mesure with ``xev`` the cu
   coordinates of your mouse.

7. Type *Cntl-C* to stop recording. Transcoding starts automatical You
   should see a file ``out.ogv`` in your working directory.

   For how to connect other recorders see: `section\_title <#connect>`__

References
==========

http://www.alsa-project.org/main/index.php/Matrix:Module-aloop


.. |winecfg| image:: images/winecfg.png
.. |RecordMyDesktop| image:: images/RecordMyDesktop.png
.. |redirect VM output in loopback device| image:: images/redirect_VM_output_in_loopback_device.png