In recent years there’s been a lot of discussion about ‘lossy’ and ‘lossless’ audio, and an ongoing debate about which is better. It is likely that debate will continue because right now the fact of the matter is that both have benefits of their own.
If you’re trying to decide whether you should choose to use lossy or lossless audio, it will help first to understand a little bit about what they are.
Understanding Audio Compression
Both ‘lossy’ and ‘lossless’ audio are types of audio compression that are used to store audio files in digital formats. Essentially audio compression is used to reduce the amount of redundant information in the audio data so that it can be stored more efficiently.
The exact methods that are used to reduce the amount of redundant information can vary, as can their effectiveness. Ultimately, however, the amount of information required to represent the uncompressed data is less than the original data – which is why audio compression (of any kind) will reduce the file size.
In short, that is the foundation that both lossy and lossless audio compression share in common – but there are significant differences between the two as well.
“What is Lossless Audio Compression?”
The key identifier of lossless audio compression is the fact that no data is ‘lost’ during its compression. In other words despite the fact that it reduces the amount of redundant information, no data is discarded and it can be decompressed into a duplicate of the original for playback.
Some of the lossless audio formats that you may encounter include FLAC, ALAC, WMA Lossless, Monkey’s Audio, MPEG-4 ALS, and WavPak. Although WAV is often thought of as lossless audio compression, it is actually often used as a container for uncompressed audio – along with AIFF.
Because it does not discard any data, however, lossless audio compression is not able to reduce the file size all that significantly. For example, a typical CD that can hold 1 hour of uncompressed music will be able to hold less than 2 hours of uncompressed music.
Although the fact that it almost halves the data used by audio may seem significant – it is anything but – especially not when compared to its counterpart.
“What is Lossy Audio Compression?”
Now that you’re aware of what lossless compression is, understanding lossy audio compression should be easier.
Unlike lossless audio compression, lossy audio compression does ‘lose’ data during its compression. In other words, it reduces redundancy by actually removing data that it considers to be unnecessary rather than simply attempting to store it more efficiently.
One of the main methods that are used in lossy audio compression is to analyze it and attempt to remove any sound that humans can’t perceive, or can only partially perceive. Other methods are also used as well, and a significant portion of the sound is either removed completely or coded with partial accuracy.
Due to the fact that data is discarded using lossy compression, audio cannot be decompressed back to its original form for playback and the quality of the audio will be affected. However at the same time, the file size will be much smaller, typically ranging from 5% to 20% of the uncompressed audio.
Arguably the most popular lossy audio compression is MP3, which is often credited for single-handedly popularizing music downloads. Because it was able to compress audio files to much smaller file sizes than previously available, it made downloading them far more feasible for average users.
Since then, however, there have been several other popular lossy formats, such as OGG (Vorbis), and AAC.
Choosing Between Lossy And Lossless
If you are in a position where you need to choose between lossy and lossless audio, you should evaluate it from several different angles that will help you to decide which option is ‘best’:
As you’re aware the file size of lossy audio formats is significantly smaller than lossless. Lossless is normally more than half the file size of uncompressed audio, while lossy is a fifth or less.
If storage space is an issue, the file size may be a very important factor to consider – especially if you’re storing audio files in bulk. On top of that, if you’re transferring files (especially over the internet), it can take much longer to store lossless audio files that are larger.
Compared to lossy audio formats, lossless audio formats have far better quality – being essentially a replica of the original sound. Lossy audio often has various artifacts such as slight hissing and are less deep than lossless audio.
Although the quality of lossy audio can vary depending on its bitrate, it is never going to match the lossless audio. However, the difference in quality may not be as noticeable on standard speakers in a room with lots of other ambient noise.
The compatibility of both lossy and lossless formats can vary – with MP3 being the exception. Because of its popularity, MP3 enjoys near-universal compatibility and can be played on practically any device or platform. Some lossless formats such as FLAC are starting to be more widely supported, but not all devices can play them.
One of the disadvantages of lossy compression that is often overlooked is the fact that transcoding it to a different (lossy) format is rarely a good idea. It will result in more data being lost, and the quality deteriorating further.
On the other hand, lossless audio can be transcoded easily, or decompressed back to the original audio. In fact, all you need is an MP3 music converter such as Movavi Video Converter and you could switch a lossless audio file to MP3 easily.
Based on the factors listed above, you should be able to figure out which type of audio compression suits your needs. If quality is important to you and storage space isn’t an issue, lossless is the obvious choice. On the other hand, if the file size is an issue or you need to play it on a device that only supports MP3 – then that is your best bet.
It should be noted that for any situation where you’re using audio intermediately (e.g. for editing reasons) it is always best to work with uncompressed or lossless audio so that no data is lost by transcoding it multiple times.