Choosing audio and video codecs and containers affects video quality and file size. Here we show you how to find the format that best suits your needs.

Decades and decades of developments in the audiovisual field have led to a result that, in some way, can be considered curious. While in other sectors, continuous development has led to a very marked standardization (think of the .doc or .pdf format), in multimedia the situation is at least compound.

An example is the world of audio formats, animated by strong “competition” and a multitude of available options. It is no less than that of video formats, in fact. In this case, in fact, we have to deal with a division between codecs and containers (we will see in a moment what they are and what function they perform) that ends up complicating things even more. Therefore, in case you want to convert a movie, you have to be careful to choose the correct codec and the correct video format, to avoid creating files that are too large or simply unreadable. In short, the error is just around the corner.

Differences between containers and codecs

Before analyzing the situation and seeing what are the most used video formats, it is necessary to clarify some fundamental concepts: first, what is the difference between the codec and the container. If in the audio world, the codec used to digitize the audio track matches the “final” file format, in the video, on the other hand, the codecs used are different from the file format that the video file will assume at the end of the digitization process. The reason is soon explained and lies in the multimedia nature of a video.

A movie, in fact, contains video and audio data: the conversion or playback software must be able to analyze both multimedia streams, and therefore will need different algorithms that work in one or another type of data stream. Codecs do exactly this: as the name, code, and decoding of data (audio and video) are made from movies, so you can convert them to another video format or play them back with a media player. Even with regard to containers, it is enough to resort to the literal meaning of the word: these are files that contain both the video and audio sequences within them and “make them available” to codecs for reading and playback.

What are the most used codecs?

A codec, as mentioned, is in charge of compressing and decompressing the video files and determines how they are played on the screen of the PC or smart TV. Each operating system provides the user with dozens and dozens of different codecs, each useful for encoding and decoding a specific type of file, even if a new one can be installed by downloading special software or packages from the web. Among the most used codecs we find the FFmpeg, Divx, Xvid, H.264 and its evolution H.265, VP9 and VP 10 (also known as the name of the Google codec).

-Divx and Xvid. As the name also suggests, these are two “mirror” codecs, created in the late 20th and early 21st centuries to meet the initial demand for online multimedia content. Since bandwidth and browsing speed were very limited, these are codecs that can guarantee good video quality even at high levels of image compression. In this way, it was possible to obtain files of contained dimensions even with very long movies (such as full movies)

-264 and H.265. Created by the Motion Picture Expert Group, they can be considered as industry standards. Among the most popular and used in all areas (you can find H.264 encoded movies on Blu-ray discs, for example, but also movies downloaded from the network) thanks to its versatility and ability to guarantee an excellent quality ratio / File size. The H.265 codec, in particular, can guarantee, with the same quality, a compression factor twice as high as that of its predecessor: files “treated” with this codec will therefore weigh half compared to their counterparts processed with H.264 codec

-VP9 and VP10. Also known as “Google Codec”, they are the codecs used by the giant Moutnain View to compress and decompress the movies uploaded to YouTube. These are algorithms optimized for online video playback, capable of offering excellent resolution and high quality even with small files. The VP10 in particular is the all’H.265 answer and is designed for resolutions up to 4K
Mpeg-H.