Overview
Years ago, you might have had a stereo with an integrated cassette tape recorder. If you wanted to record something off the radio, you'd insert a tape, wait until the song or program started, and press RECORD. Today, you can install Audio Hijack Pro, point your browser to a web page, or play an internet radio stream using iTunes, or insert a DVD into your computer, and click a button to have Audio Hijack Pro record the audio portion to a sound file.

Audio Hijack Pro, by Rogue Amoeba, is software that records any audio that you can hear playing from your computer speakers, including system beeps and bells, mp3 or wave files, sound from DVDs, or audio streams from the web. You can think of Audio Hijack Pro as the utility that can hijack and record audio playing from your computer. The audio files are digitized and saved as sound files on your hard drive for later playback and editing.

Requirements

A Macintosh computer with OS X 10.3 or higher

Setup
Setup is simple. Download the disk image and mount the image. Drag the application to your hard drive, double click the application, and you are up and running.

In Use
Audio Hijack Pro's sole use is to create files that are digital recordings of audio played on your computer. It's very easy and intuitive to use. I found myself experimenting with it immediately, and quickly discovered how easy it was to make recordings of lectures streamed from the web, all done without having read the user manual. Quicktime audio files playing on the web can often be downloaded, but streaming audio typically cannot. With Audio Hijack Pro, however, it can be done. It's similar to having a tape recorder taping your computer speakers, only the recording is done internally, so the recording is digital and clean (no room sound or distortion from analog to digital conversion).

The program is laid out logically, and the different features of the program are separated into three basic tabs: Input, Recording, and Effects. Common to all three tabs is the Component portion of Audio Hijack Pro, and the main recording and control buttons, but I'll get to those later.

Audio Hijack Pro's Input tab

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The Input tab is where you select your audio input to be recorded. It can be an application, audio device, AM/FM radio (e.g., RadioShark), or system audio. An audio device can be an internal or external microphone, or any device that can be plugged into your computer that can provide line input - a walkman, an MP3 player, etc.. System audio means it will record the audio portion of sounds made by your system, such as your beeps and bells when you make an error. System audio recording requires the addition of an additional component called Soundflower by Cycling74. The component is freely downloadable by clicking a link, but I would have preferred that the component be included with the default installation. Audio Hijack Pro has a few other extras which require additional components to be added as well. A list of those extras and their components can be found in the "Install Extras..." menu option in the Audio Hijack Pro menu.

Since it is most often the case that the initial recordings will have an audio source coming from another application, I'll be using the RealOne Player as my audio source in this test. Having selected an application to hijack on the Input tab, you then click on the Recording tab.

Audio Hijack Pro's Recording tab

On this screen, you are provided a dialog box with a full set of formats and data fields to customize your recordings. MP3, AAC, Apple Lossless, AIFF, and custom recording formats are available. The online help section at Advanced Topics > Recording Options explains each of the available formats. It explains them in simple terms that help you choose which file format is right for you, quickly and easily.

Within each format are high, medium, and low sound quality choices, as well as bookmarkable formats. As you choose lower and lower sound quality, the size of your audio file decreases - sometimes significantly so. You'll have to experiment with the different recording qualities to choose what's acceptable to you. Bookmarkable formats are what you want to choose if you'd like to make audio files that start up where you left off the last time.

Still on the recording tab, you can specify the location on your hard drive to save the file to, the name of the file, and specific actions to take, or even AppleScripts to run following the end of the recording. I'm not an AppleScript expert, but I did see that one supplied AppleScript will automatically add the newly recorded audio file to the iTunes library when the recording is finished. Other AppleScripts can be written for Audio Hijack Pro as well. See the online help for additional notes on AppleScripting related to Audio Hijack Pro.

One nice feature to the file naming is the use of variables in the file name. If you privide a name in the file name field with "%d" in it, it will expand to today's date when the file is saved to the hard drive. The variable "%n" will expand to the name of the application being hijacked. To find out more about variables that can be used in the file name field, go to the online help, click on the "Interfaces > Recording Tab" link, and you can browse the Apple developer page listing 23 other possible variables that can be used in the file naming. Variables in filenames are helpful when you create sessions, such as settings that you intend to use over and over. If you include a date variable in a file name for that session, next week's file name created with that session will be different from this week's file name created with that same session.

Actions and tags on the recording tab give you the option to segment the audio files into your choice of file sizes to make the files more manageable, to limit the amount of recording time so you don't end up recording things you don't want or fill up your hard drive, or to manage silence. You can remove silence, stop recording entirely on silence, or start a new file on silence. Starting a new file on silence can be helpful when an audio stream includes a series of songs with breaks between them.

The tags portion of the Recording tab gives you the ability to add helpful, informative tags (ID3 tags for MP3 files) to the files you create. The informative tags include Title, Artist, Album, Genre, Year, Comment, and Track #. Some audio players display this information in a window as the file is playing. You'll have to see the user manual for your particular player to see if the tags are displayed or not.

Having selected the input and having set the recording options, click once on the "Hijack" button to hijack the audio from the selected application. Hijacking an application doesn't start the recording - it only sets up the ability to record. You still need to click the Record button.

In order for Audio Hijack Pro to intercept an audio stream, the user must either select the audio stream and then restart the Audio Hijack Pro, or install the "Instant Hijack" extra such that a permanent hook is installed (with Instant Hijack, you don't have to restart the app after selecting an audio stream). I don't see why anyone would not want the Instant Hijack installed, as it is far more convenient. Therefore, I would prefer that Audio Hijack Pro simply include these extras in the default installation right from the start.

Finally, click the "Record" button and the audio capture begins. I noticed that the application is intelligent enough to know when it's audio stream is dead silence or not. If it encounters dead silence when recording audio that's streaming from a web browser, it patiently waits for the actual sounds to start before it begins building the sound file. When the audio stops, the recording stops as well, too. This is a very nice feature. There's even a "Mute" button for when you're recording, but you're busy doing other work and don't want to have to listen to what's being hijacked. Other control buttons include a"Pause" button, and a "Split" button for seamlessly ending the current audio file and creating a new one, usually by appending a -1, -2, -3, and so on to the file's name.

Audio Hijack Pro's Effects tab

I didn't mention the effects tab above because I don't usually use it for audio streaming from the web. In fact, even without the effects features, Audio Hijack Pro is worth the price of admission. The icing on the cake is that it does have dozens of audio tools that can be used to enhance or modify the incoming audio. By clicking and holding your mouse button down, a hierarchical pull-down menu appears providing you with 50 different sound tools and filters. You'll love playing with them and experimenting with the different possible effects! Effects are added in the order you select them. You can remove effects by clicking on them and hitting the delete key. If you never add any effects to the Effects tab, then you get a plain, standard recording.

Performing an experiment for a friend, I used the effects tools to reduce the background noise in an interview with her late father, recorded on a hand-held mini-tape voice recorder back in 1991. I connected the player to my G4 using a stereo male to male connector (the tape player was my line input). I then selected the player as my audio device on the Input tab, and provided the details on the Recording tab. On the Effects tab, I selected three effects filters to filter out noise and certain frequencies. Using this setup, I was able to eliminate some of the background noise so her father's voice could be heard more clearly. Not once did I have to look at the online help or any user manual. I like it when software is that easy to use, yet is so powerful!

The Component Window
The Component portion of Audio Hijack Pro provides access to the Recording Bin (a collection of recordings made by Audio Hijack Pro), a Quick Record option, and Sessions. A session is a particular combination of Input, Recording, and Effects choices. After having made your choices on the three tabs, you can create a session and reuse it with the same settings. This is great when you're going to be recording audio from a particular source at a later time repeatedly. Quick Record gives you a one-page dialog box to record quickly without adding any special effects or other features. The Recording Bin gives you options to preview recordings, send them to iTunes, burn them to CD, run an AppleScript against it, or delete it.

Audio Hijack Pro's Quick Record panel

Timers
You can program Audio Hijack Pro to record audio for you when you're not around. Go to the Input tab, select a session, click the plus (+) below the Schedule, and a timer is created that you can personalize to record based on the day of the week and time of day. It is very easy to configure. The timer's options are explained simply and clearly in the online help. I did note that timers will wake your Mac from sleep to perform a recording session, but it cannot start a Mac that's been shut off.

Interface
Audio Hijack Pro has an interface that focuses on functionality and practicality rather than style, so there's no bright colors or unnecessary or distracting graphics. Yes, it's plain, but I don't care about that when I'm using a powerful utility to capture audio to a file. I don't think any skins are available, but even if there were, I doubt I'd use them - they don't change the usefulness of the application. I think the simple, no-nonsense layout is one reason I was able to learn its operation so quickly.

The overall interface is decidedly Macintosh, with the usual Aqua interface highlights pointing to which fields have the focus, so any Mac user who's used to using recent, well written utilities or applications will feel right at home. Menus items thoroughly cover the utilities features and are intuitively named, and submenus appear to be complete and organized in a way that keeps related items together - a sign of a well written application that cares about its users.

Online Help
When I first used the program, I missed a huge portion of the application's features because I didn't browse the online help. My biggest hint to you would be to click on each of the help items to see what else is hidden inside the program. In the online help, you'll learn things such as recording the audio portion of a band's "Live and in Concert" DVD. I didn't think about making my own podcasts, but Audio Hijack Pro does support this. I had no idea I could record separate audio streams at the same time - not overlapping audio, but two separate sources to two different audio sound files. I can also customize Audio Hijack Pro to record my voice chats on Skype or other audio chat applications.

According to the online help, the recordings Audio Hijack Pro makes are bulletproof - meaning that all audio is captured in real time and none of it is lost should there be a kernel panic. That's pretty sophisticated.

Audio Hijack Pro's website provides helpful resources as well.

Summary
Audio Hijack Pro fills a big need for those who need or want to capture the audio portion from many different types of input streams on your Mac. It supports input from AM/FM radios, web radio, DVDs, web pages, sound clips sent in email clients, microphones, tape players, and so on. Basically, if you can hear it, you can have Audio Hijack Pro record it. You can also use it to create your own podcasts, and you can even schedule to wake your Mac up and do the recording for you while you're away. Audio Hijack Pro includes a lot of options and features, such as choosing the sound quality for saved files, resume recording features, audio segmenting, and 50 included effects tools and filters to customize the recordings. Whether you're a sound person or have a background in sound engineering, a hobbyist with a need for occasional records from the web or other media inputs, or if you're just curious and like to experiment and dabble with sounds, this application is worth a look and a listen. If you are looking for a way to digitally record any audio that plays from your speakers, Audio Hijack Pro is a must-have utility. Rogue Amoeba claims that it is the cornerstone of your digital experience, and I can confirm that this is very true. For such an inexpensive license, Audio Hijack Pro is a great, clean utility providing an incredible amount of power and function.

Pros

• Easily capture audio from audio streams
• Multiple file formats supported
• Clean, logical layout of screens
• Powerful effects library
• Online help is clear and simple
• Customizable options for saved files
• Timers provide additional functionality and usefulness
• AppleScriptable

Cons

• Addition of extra components preferred to be part of the default installation
• Requires learning curve to fully take advantage of its more sophisticated effects features

Overall Rating

5 out of 5 Mice