What are bitrates? How do they affect the quality of music and video?

Bitrate is indicated as one of the main characteristics of video and audio. Most users are used to thinking that it determines the quality of the downloaded file. But what are bitrates and how do they actually characterize music files and videos? Let us consider this in more detail.

What are bitrates?

Bitrate is a value that displays the number of pieces of information (megabit or kilobit) that are contained in one second of the file's playback. Accordingly, it is measured in megabits per second (Mbps) or kilobits per second (Kbps). Otherwise, the bitrate can be characterized as the width of the bandwidth. This feature is important for those who want to convert files, because for the same duration, a larger bitrate will lead to an increase in the file. In addition to the size, the quality of the sound also changes. Reducing the size when you decrease the bitrate is called compression.

A popular MP3 music format is an audio file compressed to such an extent that up to 12 hours of music can be placed on a standard disc. At the same time, the quality remains high due to psychoacoustic compression: from the entire range, sounds are removed with those frequencies and loudness levels that are not captured by the human ear. Selected sounds are formed into separate blocks, called frames. Frames have the same duration of sound and are compressed according to a given algorithm. When music is played, the signal is reconstructed from the decoded blocks in a certain sequence.

What compression is usually used?

Bitrate audio is usually 256 kbps. At this value, the audio recording is compressed in size about 6 times, so that one disc can record 6 times more music than before compression. If the bit rate is reduced to 128 Kbps, then one disc will fit 12 times more music, but the sound quality will be noticeably lower. Music recorded as 128 kbps is most often offered for listening on the Internet, because in the pursuit of increasing the speed of loading pages, resource owners go to any sacrifices. Many users note that its quality is far from ideal.

Now, when it became clear that such bitrates, it's time to determine their optimal level. Both amateurs and professionals endlessly argue how the bitrate affects the sound quality and whether it affects at all. On music albums, as a rule, the bitrate is indicated. The same disc recorded as 128 Kbps and 256 Kbps will differ in price by a factor of two.

Optimal bitrate under different listening conditions

For many people twelve-fold compression does not represent any damage, while others claim that they can not listen to music with a bitrate lower than 320 Kbps. Paradoxically, both are right. The thing is that ultimately the quality of the playback depends not on the compression level, but on the playback conditions and even on the type of music.

For example, a song is played on a tape recorder installed in a domestic car. In this case, the quality at 192 kbit / s will be quite sufficient. A higher bitrate will improve the sound quality, but the difference will not be noticeable due to the high noise level during the trip. If the music is played on a home computer or a portable player, then at least 256 Kbps is required. If the signal is not changed, transferred to external devices and displayed on expensive imported speakers, it should be possible to use minimal compression if possible. It is possible with a bitrate of 320 kbps.

Optimum bitrate for different music styles

Music with high bitrate is not always necessary. Popular music, as a rule, sounds good enough at a bitrate of 192-256 Kbps. You can install a higher quality, but there is no point in it: pop songs are short-lived, so keeping the space on the discs should be a priority. In addition, the quality of the original recordings is also mediocre, so increasing the bit rate may not affect the quality of the file being played. For listening in transport and at informal parties of average quality is quite enough.

If we are talking about classical music, the works of legendary rock bands or rare author's songs, then the quality should be above all. When purchasing such music, you need to look at the bitrate indicated on the disc package. If the song is downloaded from the Internet, this information should be on the download page. In addition, the bitrate is displayed in the player during playback.

Bitrates of video files

Above it was said that such bitrates of audio recordings. But what is a bitrate of video? Given that the video is reproduced as a sequence of sounds and images, the definition of bit rate will be similar. The presence of the video makes the file heavier, but ultimately the images for the processor are the same zeros and ones as the sounds. The principle of encryption of information is the same for all types of files.