Digital Speech Standard developed in 1994 to store voice audio data in a highly compressed format. Used primarily for digital dictation recorders, thanks to basic recording functionality and the ability to enter into overwrite mode.

Free Lossless Audio Codec is a lossless compression format of digital audio. Files compressed using this format can be reduced by 50 to 70 percent of their original size and contain an identical copy of the original audio data. More about converting FLAC to text here.

M4A is a file extension for the MPEG-4 Audio format. An M4A file can contain both audio and video, but is more commonly used for audio-only files.

M4A files are similar to MP3s, but they’re not exactly the same. They’re lossy compressed, so you’ll notice some degradation in quality compared to uncompressed formats like WAV or FLAC. However, they’re still very good at preserving audio fidelity while saving space on your hard drive.

Because of this difference in compression, M4A files will typically take up less space than MP3 files of the same length or bitrate. The exact amount of storage savings will depend on whether you’re using lossless or lossy compression and which bitrate you select when creating your M4A file.