Can I record sound being played back from the machine as well as sound captured from the microphone?

Asked by Tomislav

I would love to record video conferences. As it stands, kazam seems to only record audio from the microphone so the person on the other side appears muted.

It would be excellent if Kazam could mix audio from the microphone with sound being played back from the sound card.

recordmydesktop shows that this can be done, but it has other shortcomings (e.g. consistently hangs during longer recording sessions) which make it a non-option.

Can kazam be configured to support this or does it require modification of the application?

I'm using version 1.0.4.1-0ubuntu2 on Ubuntu 11.10.

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David Klasinc
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David Klasinc (bigwhale) said :
#1

I am not sure if I understand. You would like to record sound from two different sources? Kazam 1.0.4 version can already do this. Make sure you have both audio sources enabled and that volume is set correctly.

If you have some sort of specific video conference software that is not using PulseAudio for sound, then I am not sure what Kazam will record.

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Tomislav (hefest) said :
#2

Hi David, thanks for the response. I've made a mistake in my question (saying recordmydesktop performs this specific job) so I'll explain on an example.

Suppose you wanted to record a screencast with an musical background. You start the music, start doing whatever it is you want to show in the screencast and speak into the microphone to provide explanations.

If you recorded such a session using kazam, you would only capture the screen and your voice from the microphone, while the musical background would be missing, I guess because it ends up on an output and not an input channel of the soundcard.

A second scenario would be recording a video call: you want to capture sound from both sides of the connection.

Can kazam be used to make such a recording?

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David Klasinc (bigwhale) said :
#3

Kazam can in fact do that. You have to select correct audio sources in order to record sound output of your computer. Usually there is a "Monitor" device for your sound output. For example if your output device is called "Stereo Internal Audio" then the monitor device will be called "Monitor of Stereo Internal Audio". You will have to select this monitor device.

You will also have to check volume levels of monitor device and volume level of the device itself.

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Tomislav (hefest) said :
#4

Thank you for the suggestion. However, in effect it confirms that something isn't working properly.

I have an "Internal Audio Analog Stereo" output device and Kazam does make it possible for me to record input from a "Monitor of Internal Audio Analog Stereo", but when I try to record that way, the recording is completely silent.

I imagine it is not a matter of mixer settings because if it were, the video conferences I take part in would also be mute. Does the "monitor of" input source somehow have to be enabled to work?

These is how I tried:
Kazam configuration: http://www.screenshots.cc/show/59004/r5n3f
Input settings: http://www.screenshots.cc/show/59005/s9y5j
Output settings: http://www.screenshots.cc/show/59006/gn7xx

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Best David Klasinc (bigwhale) said :
#5

Set first audio source to your microphone, your second audio source to "Monitor of Internal Audio". Then make sure that volume for "Internal Audio" _and_ "Monitor of Interal Audio" is set and none of the devices are muted.

To check monitor devices you will need pavucontrol utility which you might need to install separately.

If you still have problems with it, please submit a bug report and attach a full output of kazam -debug and /tmp/kazam_debug.dot file.

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Tomislav (hefest) said :
#6

Sure enough, that fixed my problem.

The pavucontrol input control tab shows the button I had to press: http://www.screenshots.cc/show/59008/c9yc5

On the one hand, I'm happy to have found a solution to the problem, but on the other I'm a bit depressed by the fact that functionality as basic as this is burried hopelessly far from an average user in a Distro for Human Beings. To be able to record this way, users have to install an additional volume control tool (I haven't seen this setting in the default mixer or even in alsamixer), understand what an "monitor of..." is and notice that it is off by default (?).

Ah well. I certainly appreciate the excellent direct help you provided!

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Tomislav (hefest) said :
#7

Thanks David Klasinc, that solved my question.

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Makario Lewis (makariolewis) said :
#8

Is there any way that Kazam can automatically unmute the Monitor to make it "just work"?
It's an unintuitive hoop that beginning users may not be able to jump through.

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Pablo Estigarribia (pablodav) said :
#9

http://youtu.be/vtc_wTqt-Vg Icould get it! work with pavucontrol.