They end with a period followed by three or four letters. It is what happens with absolutely all the files of a computer or a smartphone. These last letters represent the format in which said file is. Today we are going to focus on one type of format, the lossless format.

What is a lossless format?

Any element in a computer has to have some kind of format, or so to speak, some kind of structure that is known by that computer so that it can work with the file. In a parallel with the world of physical objects, the format would be something like the material with which the object is constructed.

Just as there are different materials with different properties, there are also different formats with different characteristics. Most of the files we use today have a compressed format, so they take up less space on our computer and are easier to send via the Internet, or upload to a social network. However, these formats are not the highest quality, since this position would be occupied by lossless formats. These formats retain the original quality of the file, and are the ones that offer the best results.

If we talk about images, the lossless formats are RAW, BMP and PNG, among others. Meanwhile, the compressed formats are JPG and GIF. However, there are certain differences with some of them. RAW, for example, stores all the light data captured by the camera’s sensor. It is a perfect format for photographers. But it would not even be for photographers who want to share a particular photograph on a social network. A RAW photo can easily occupy 25 MB, depending on the resolution of the camera. A high quality JPG photo would be a photograph that would occupy two or three megabytes, although it would have less quality.

If we talk about audio, there are three main formats without loss: WAV, FLAC and ALAC. The latter is the one used by Apple in iTunes. They are formats that do not lose any quality with respect to the original audio. Yes we would be losing quality with MP3 and OGG.

And if we talk about video, there are few lossless formats that we can talk about. In fact, there is a problem, and storing videos without loss would be an impossible task for anyone who did not have a storage server nearby. That is why we usually opt for the MKV, WMV, and H.264 formats. Of course, the latter is much better, because the compression process is much more intelligent.

Compression, how does it work?

Now, what is this about compressed formats? As the name implies, we are talking about formats that reduce files, and we can rely on it to perfectly understand how these formats work. Surely we have all seen ourselves in the situation of having to pack a suitcase with just the right space, finish choosing all the clothes we are going to take on a trip, and finally have to decide what we can do without being able to close the suitcase, because we had too many clothes. For that is the compression of each of the formats. They remove items from that file, and thus make them weigh or occupy less.

Why are there different formats? Returning to the case of the suitcase, each person will make different decisions regarding those things that he can do without for his trip. It will vary from one person to another. The same goes for formats. The developers of these reduce the space occupied by a file, but each of the formats deletes data in a different way, so that a file compressed to JPG, can be different from one GIF, even if the two are compressed. Each of them has followed a different procedure to delete the data, and that the song, image, or video, continue to play almost the same as the original version.

When to convert from compression to lossless?

The question that heads this paragraph is especially important for all those who at some point have converted a file from a compressed format to a lossless format. And, in fact, it goes with a trap, because you should never convert a file from a compressed format to a file without loss. In reality, nothing happens if we do, but we will not improve the quality of that file, although it will now be available in a format in which the files are not compressed.

Of course, it is also not a good idea to convert a file into a compressed format, to a different compressed format. Let’s keep in mind that each compression process is different depending on the format chosen. That is, each format eliminates the data it deems appropriate to maintain image quality. If we have a file in a compressed format, that will mean that it no longer retains all data.