Bit rate is indicated as one of the main characteristics of video and audio recordings. 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's consider it in more detail.
What are bit rates?
Bitrate is a value that displays the number of units of information (megabits or kilobits) that are contained in one second of file playback. Accordingly, it is measured in megabits per second (Mbps) or kilobits per second (Kbps). Otherwise, the bit rate can be described as the bandwidth. This feature is important for those who want to convert files, because at the same duration a higher bitrate will lead to an increase in the file. In addition to size, the sound quality also changes. Reducing the size while lowering the bitrate is called compression.
The common MP3 music format is an audio file, compressed to such an extent that up to 12 hours of music can fit on a standard disc. At the same time, the quality remains quite high due to psychoacoustic compression: sounds with those frequencies and volume levels that are not captured by the human ear are removed from the entire range. Selected sounds are formed into separate blocks called frames. Frames have the same sound duration and are compressed according to a given algorithm. When music is playing, the signal is recreated from the decoded blocks in a specific sequence.
What compression is commonly used?
The audio bitrate most often is 256 Kbps. With this value, the audio recording is compressed at a rate of approximately 6 times, so that you can record up to 6 times more music on one disc than before compression. If the bitrate is reduced to 128 Kbps, then 12 times more music will fit on one disc, 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 faster page loading, resource owners make any sacrifice. Many users note that its quality is far from ideal.
Now that it has become clear what bit rates are, it's time to determine their optimal level. Both amateurs and professionals endlessly argue about how bitrate affects 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 half.
Optimum bitrate for different listening conditions
For many people, twelvefold compression does not represent any damage, while others claim that they cannot listen to music with a bitrate lower than 320 Kbps. Paradoxically, both of them are right. The fact is that ultimately the quality of reproduction does not depend on the degree of compression, but on the conditions of reproduction 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 the level of 192 Kbps will be quite sufficient. A higher bitrate will improve 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 portable player, then at least 256 Kbps is required. If the signal is not subjected to changes, is transmitted to external devices and output to expensive imported speakers, then you should resort to the minimum compression if possible. It is possible at a bitrate of 320 Kbps.
Optimal bitrate for various music styles
High bitrate music is not always needed. Popular music, as a rule, sounds good enough at a bitrate of 192-256 Kbps. You can set a higher quality, but there is no point in it: pop compositions are short-lived, so saving disk space should be a priority. In addition, the quality of the source records is also mediocre, so increasing the bitrate may not affect the quality of the reproduced file. For listening in transport and at informal parties of medium quality it will be 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 bit rate indicated on the disc packaging. If the song is downloaded from the Internet, then such information should be present on the download page. In addition, the bitrate is displayed in the player during playback.
Bitrates of video files
It was said above what the bit rates of audio recordings are. But what is video bitrate? Given that the video is played as a sequence of sounds and images, the definition of bitrate will be similar. The presence of a video footer makes the file heavier, but ultimately the images for the processor are the same zeros and ones as the sounds. The principle of information encryption is the same for all types of files.