Your Mac is purpose made for multimedia creation and consumption. Built in tools help you manage and organise documents, photos, videos and audio. That last category, audio, is sometimes overlooked though. Perhaps the Mac’s reputation as the computer that visual designer’s love overshadows the powerful features your Mac gives you to manipulate noise. But those tools are there - and we’re here to highlight your Mac’s mastery of sound.
Macs have sound right at their core. Core Audio is a sophisticated set of built-in protocols at the heart of OS X. Both QuickTime and iTunes - free programs bundled with your Mac - use Core Audio extensively to enable you to record, process, edit and playback sound on your computer.
In this tutorial, we look at ten gems of Core Audio wisdom. We look at ways you can crop and trim sound, extract tracks from video and record without any extra tools. Everything we use is free or bundled with your Mac.
Rip Audio from Video
Love the soundtrack in a clip or want to extract audio from video to process it? The current version of QuickTime allows you to do that. Open a clip in QuickTime Player, then go to File > Export. Select “Audio Only” from the Format drop-down in the save dialogue. Give the file a name and Export it. This extracts just the audio in M4A format.
Trim Tracks with QuickTime
You can use a similar trick to crop audio down. Open an audio track in QuickTime Player. Go to “Edit > Trim”. A yellow slider pops up around the waveform. You can adjust this to select a section of audio or just trim silence from the beginning and end. When you’ve finished nudging the handles, export as audio.
You can use QuickTime Player to record audio from external sources or your mic. Go to File Menu and choose New Audio Recording. Click the white arrow to open recording options - including source (Microphone or Line-In) and Quality. To begin recording, click the red Record button. The recording is automatically saved in your Movies folder with a .mov extension.
Extend QuickTime’s audio and video capability with Perian - a project to add open source decoders to QuickTime’s core. The project is about to release its final version at www.perian.org. It adds Vorbis and and Windows Media Audio playback, among others - but will no longer be supported after the final version’s release.
Convert to AAC
QuickTime’s conversion capability is built directly into OS X now, as a service. Select an audio track or marquee around multiple tracks in . Go to the Finder menu and choose “Services”, then “Encode Selected Audio Files”. You can then choose the quality that the file will be converted to and where to save the result before encoding.
iTunes Batch Conversion
You can also batch convert files in iTunes. First, to select the format you wish to convert to, open iTunes and go to iTunes > Preferences > General. Click the “Import Settings” button and choose an audio format. Next select a song or multiple songs in iTunes. Go to “Advanced” in the main iTunes menu. Choose “Create
Trim Tracks in iTunes
Play back the track you want to crop and note the start and end times in the status pane. Next select the track you wish to split in the iTunes Library, CTRL click on it and choose “Get Info”. Enter the start and stop points in “Options” and tick the appropriate boxes - then click “OK”. Finally, click “OK” then go to “Advanced” and choose “Create
Split Long Tracks
You can use the same technique if you’ve a long recording to split the file into smaller chunks using iTunes. For example, if you have a recording of one side of an old vinyl LP. Find the start and stop points for track 1, enter them in Options, then create a version of the selection. Rename the file, then repeat for track 2 until you’ve split the longer file into individual tracks. Finally, delete the original.
Batch Edit Information
When you’ve finished splitting the files you can quickly and easily add bulk information to them all. Hold down SHIFT and click on the first and last file to select them all, then CTRL click to bring up the contextual menu. Choose “Get Info”. You can enter common data, like the Artist and Album title, then edit each track individually.
Audio Unit Plugins
Your Mac ships with a raft of Audio Unit format plugins, that are effectively hidden unless you have a sound editing program installed. You can get GarageBand from the App Store - or you can download Audacity for free from audacity.sourceforge.net. This will allow you to apply high quality filters and equalisation to audio files from the Effect menu.