what you hear

Hello from Washington DC. Im running Audacity 2.0.2, compiled from source to run under Centos 6.6.

Here is my situation: I work in a newsroom and need my computer to record audio from a TV cable box (connected to my soundcard Line In), AND to be able to record audio from streaming videos et al viewed in my browser. Once upon a time under Windows, I could do this with the old Creative “What You Hear (stereo mix)” feature that would roll on whatever was selected to come out the Speaker Out line. But the bullpen is going the Centos route, even before it was proven that this was possible or even feasible.

I cannot do this with the existing MoBo audio chipset and am considering a proper soundcard that would let me work within the AlsaMixer, to allow me a rapid switch between incoming Line In audio and the equivalent of What You Hear. If anyone has a way of doing this successfully, I really could use the procedure and a hardware recommendation.

Thanks very much.

In my opinion, the “best” way to do that would be with two computers and a little mixing desk. Use one computer to play the streaming audio (could be a $50 second hand piece of junk as long as it works) and output that into the mixer. Use another mixer channel to handle the TV cable box. Use your main computer to record the mix.

Yes it is “possible” to handle the whole thing in one Linux computer (as you did with XP), but better to do the job properly. The hardware route provides much better control over the mixing process than you ever had with the XP set-up, and is much more flexible - want to add a live commentary? just plug a mic into the mixer.

Steve, thanks very much. That’s worth trying.
Both desk space and spare computers are at a premium here – there are a great many of us here in the bullpen. What I need to know is, is this possible inside one machine, say with a second soundcard that can be looped through and with whatever the Linux equivalent of “What You Hear” might be?

The equivalent of “What U Hear” on Linux is to record from the “Monitor” input in PulseAudio. See here for details: http://manual.audacityteam.org/o/man/tutorial_recording_computer_playback_on_linux.html

However, that will only allow you to record the streaming audio and not the live input at the same time. The way to get around that is to use “Jack Audio System” (“jackd”) rather than PulseAudio. This can be a bit tricky to set up (Google is your friend), but it can provide a very powerful and flexible audio routing system within the computer.

Jack is a low latency audio server that runs on top of the base sound system (usually ALSA). In that sense it is a bit like ASIO on Windows, but Jack has another trick up its sleeve which is that it can make virtual audio connections between different audio applications. In this sense it is a bit like “Rewire” on Windows.
See http://manual.audacityteam.org/o/man/tutorial_recording_computer_playback_on_linux.html#jack for details.

The general idea is that you use an intermediary “dummy” application between the things that you want to record and Audacity. I usually use “Jack Rack” if I need to do this, but a “Jack Mixer” would provide more control. Send the output from the application that is playing the streaming audio AND the inputs of your sound card to the inputs of the intermediary application. Then set Audacity to record from the intermediary application.

(if there is no suitable Jack aware applications for playing the streaming audio, then you would need to install “pulseaudio-module-jack” so that you can connect the application to Jack via PulseAudio).