Cerebro Seco - Mot-clé - recording
Se faciliter la vie informatique sans sacrifier ses principes!
2024-03-10T05:04:05-05:00
Cubytus
urn:md5:b6941165ae8c2dab9d34169f224d6f7b
Dotclear
Record bidirectional audio using JACK audio
urn:md5:8bbd8da4c605f986166e4f2fc481f2ef
2013-09-02T16:37:00-04:00
2013-09-08T15:06:34-04:00
cubytus
jack
recording
sound
<p><em>Ever wanted to record what's playing in your Mac? Unfortunately such a simple process has been made difficult by, well, I don't really know. First things first, many commercial software actually enable you to record from any source to any destination, being it a mic, an application, external audio interfaces, but they are quite expensive.</em></p>
<p><em><ins>Difficulty</ins>: medium to hard<br /></em></p> <p>So, let's sacrifice (again) commodity for open-source. To understand what this post is about, here is a quick-and-dirty drawing of what I wanted to do. For some reason, the people who helped me consider options kept on thinking there was some kind of external hardware involved in the process, or dubbing of an already-existing soundtrack, in simpler words, overly complicating what is a very simple goal. The tricky part was finding the right "Tap Application" for the job.</p>
<p>Two different cases, one where a sound coming in from the mic would be recorded at the same time as a sound from an application, while allowing sound to come out in the speakers, another when the application runs full duplex.</p>
<p><img title="Schem_1_557.jpg, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Schem_1_557.jpg" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/.Schem_1_557_m.jpg" /><img title="Schem_2__558.jpg, sept. 2013" style="float: right; margin: 0 0 1em 1em;" alt="Schem_2__558.jpg" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/Schem_2__558.jpg" /></p>
<p>So first start by downloading an installing <a hreflang="en" href="http://jackaudio.org/">Jack OS X</a>. It's a rather old version, but still does the job correctly. </p>
<h3>First step: Adjust settings</h3>
<p>Start JackPilot from the Jack folder in your Applications folder. Two small windows should appear, one for the preferences, one for controlling JackRouter, the back-end process doing all the dirty work.</p>
<p><img title="Capture_d_e_cran_2013-09-02_a__17.12.21.png, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Capture_d_e_cran_2013-09-02_a__17.12.21.png" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/Capture_d_e_cran_2013-09-02_a__17.12.21.png" /></p>
<p>If this is the first time you start, at least have a look at the preferences by yourself. Default ones will do the job properly, but it always pays to get an overview.</p>
<p><img title="Capture_d_e_cran_2013-09-02_a__16.30.03.png, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Capture_d_e_cran_2013-09-02_a__16.30.03.png" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/.Capture_d_e_cran_2013-09-02_a__16.30.03_m.jpg" /></p>
<p>For the applications listed above, both your Input and Output should be set to <em>Integrated in</em> or <em>out</em>. If you have different devices that can send or receive sound to or from your Mac, they should be listed here.</p>
<p>Virtual input / output channels: unless your application, at the right of the drawing, uses more than two channels (stereo operation), leave this alone. For the recording application, it may be useful to provide more than two channels if it supports it, but most of the time you will want to get a mixed, stereo track. Hence, two channels are ok here.</p>
<p>Auto-connect with physical ports should be left checked at all times. Some advanced applications may require that you uncheck it, but that won't be covered here.</p>
<h3>Second step: Start JackRouter</h3>
<p>Click on Start, then on the Routing button that is now active. This will show you the following arcane window:</p>
<p><img title="Capture_d_e_cran_2013-09-02_a__17.31.23.png, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Capture_d_e_cran_2013-09-02_a__17.31.23.png" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/.Capture_d_e_cran_2013-09-02_a__17.31.23_m.jpg" />In the <strong>left pane</strong>, applications and devices that output sound.</p>
<p>In the <strong>middle pane</strong>, applications that can receive sound. Please pay attention here, as some recording applications, such as Audacity, will only appear when you start an actual recording. This is silly as it will leave a blank space at the beginning, but you can always cut it later.</p>
<p>In the <strong>right pane</strong>, established connections are indicated. In fact, you can route as many input to as many output as you like.</p>
<h3>Third step: Tapping the connection</h3>
<p>This is the trickiest part, as you need to get everything synchronized by hand.</p>
<p><ins>First</ins>, <strong>start JackRouter</strong> clicking on the Start button you saw previously.</p>
<p><img title="Capture_d_e_cran_2013-09-02_a__19.17.14.png, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Capture_d_e_cran_2013-09-02_a__19.17.14.png" src="https://websrv3.q-x.ch/%7Eftp83plu/dc/dotclear/public/Soundflower/.Capture_d_e_cran_2013-09-02_a__19.17.14_m.jpg" /></p>
<p><img title="Capture_d_e_cran_2013-09-02_a__19.17.28.png, sept. 2013" style="float: right; margin: 0 0 1em 1em;" alt="Capture_d_e_cran_2013-09-02_a__19.17.28.png" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/.Capture_d_e_cran_2013-09-02_a__19.17.28_m.jpg" /></p>
<p><ins>Second</ins>, make sure JackRouter is set up both as your input and output device.</p>
<p><ins>Third</ins>, click on Routing in the previous window, then <strong>start playing the sound</strong> in your application, the one on the right as on the drawing. It should appear in the left pane of your router, and add itself below the system device, containing the microphone ("capture" device).</p>
<p><ins>Fourth</ins>, <strong>start recording application</strong>, and make sure JackRouter is set up as the input device. For some strange reason, Audacity didn't appear in the middle pane right away. For this software to appear in the middle pane, you need to start an actual recording. Click on the Record button. If everything is correctly configured, you should see a flat line, as you just turned on the sound router, but didn't route anything through it yet.</p>
<p><img title="Capture_d_e_cran_2013-09-02_a__19.16.05.png, sept. 2013" style="float: left; margin: 0 1em 1em 0;" alt="Capture_d_e_cran_2013-09-02_a__19.16.05.png" src="https://dc.ftp83plus.net/~ftp83plu/dc/dotclear/public/Soundflower/Capture_d_e_cran_2013-09-02_a__19.16.05.png" /></p>
<p><ins>Fifth</ins>, while sound is playing, make a <em>single click</em> on the name of the application playing a sound, then a <em>double-click</em> on the recording application. </p>
<p>Do the same making a <em>single click</em> on System > capture, then a <em>double-click</em> on the recording application.</p>
<p>Now, you should be recording both the microphone input and the audio coming out of an application.</p>