Apple Lossless (also known as Apple Lossless Encoder, ALE, or Apple Lossless Audio Codec, ALAC) is an audio codec developed by Apple Inc. for lossless data compression of digital music. Apple Lossless data is stored within an MP4 container with the filename extension .m4a. While Apple Lossless has the same file extension as AAC, it is not a variant of AAC, but uses linear prediction similar to other lossless codecs such as FLAC and Shorten. iPods with a dock connector (not the Shuffle) and recent firmware can play Apple Lossless-encoded files. It does not utilize any digital rights management (DRM) scheme, but by the nature of the container, it is thought that DRM can be applied to ALAC much the same way it can with other files in QuickTime containers.
Because of its exceptional performance and quality, Advanced Audio Coding (AAC) is at the core of the MPEG-4, 3GPP and 3GPP2 specifications and is the audio codec of choice for Internet, wireless and digital broadcast arenas. AAC provides audio encoding that compresses much more efficiently than older formats, such as MP3, yet delivers quality rivaling that of uncompressed CD audio.
Once Audio Converter Plus is installed properly, launch it and click on the "Add File" button on the tool bar. The standard file open dialog appears. Select "ALAC - Apple Lossless" in its "Files of type" combo box. Select the file(s) you want to convert and click "Open". The file will be added to the conversion file list.
Use the setting panel on the bottom of the window to control the output format. Click on the toggle to the left of the "Format" label to expand the panel. Select "M4A - MPEG-4 Audio" as the "Audio Type".
Expand the "Output Directory" panel. Use the "Browse" button to select an output directory.
Click the "Convert" button on the tool bar, the conversion task will be started immediately.