Lossless or lossy? Open or licensed? Even if you’ve already got a YouTube MP3 converter for Mac, you still have to choose the format. It’s a matter of compatibility, quality, portability and basically everything else. There is no objectively "wrong" format, but depending on your needs, selecting some formats could lead to useless files that don’t fulfill your needs. To save yourself time later, read up now.
MP3 is both a container file and a compression format. When compared to raw audio data, it can reduce file size by a factor of 12. Of course, there are drawbacks. During compression, some quality is irreversibly lost. An MP3 can never be restored to its initial quality, so it may be a poor choice for archivists.
On the other hand, if you don’t care about hi-fi sound, it will allow you to pack dozens, if not hundreds of albums on a single SD card. And how would we rate the best YouTube converter if it didn’t exist?
The AAC-encoded M4A file is the designated successor to MP3. While the world stubbornly refuses to move on, and a ton of data is still kept in MP3, this "newcomer" offers an objective improvement on the quality to size ratio.
The stigma on M4A is absent from Apple platforms and devices, as the company proves time after time its dedication to MPEG formats. But even on other systems, compatibility is hardly an issue nowadays. Media players try to reach as many formats as they can.
OGG (Vorbis, FLAC)
OGG is a container format. Though unassuming, it is a part of a well-developed open-source multimedia framework. And the framework includes a vast number of various codecs, both lossy and lossless, that are intended for specific tasks. Depending on its codecs, an .ogg file can be best suited to streaming, podcast audio, normal everyday music or even ultra-HQ audio preservation. And all of that comes with metadata support. We will give 2 examples of OGG-supported codecs: Vorbis and FLAC.
The most popular OGG codec is Vorbis. It has a broad range of workable bitrate, decent compression and compatibility. This is the codec you want for everyday use: songs, audiobooks, recordings, etc. There’s not much to say about it outside of technical stuff; in practical terms, the quality is comparable to MP3 and AAC.
And how could we forget FLAC? While it doesn’t provide shrinkage at the same level as MP4, only about 50 to 70%, the audio file can be restored completely, without a single bit of data loss (unless there is a malfunction). Though there are often arguments on whether the human ear can even sense the difference between high-quality lossy and lossless audio, it’s still nice to have the option.
Windows Audio Interleave is a slightly-dated, proprietary format. While it has some serious limitations, and generally larger filesize, there are some notable features, such as XMP metadata support. It’s a poor choice for general use - only go with this one if you have specific demands and in-depth knowledge of media technology.