What is the video and audio bit rate?
Do you like video production or do you value high quality in movies? You’ve probably come across something like bitrate. It always accompanies the technical characteristics of video recordings and its value determines the quality of the image in the file. When working with converters, you will come across this feature more than once, so it is advisable to fully understand what it is responsible for and how it affects the final product: a video or an audio file.
To find out what bit rate is, it is worth understanding how video information transmission works. Any video is a rotating sequence of images. In order not to have a “slideshow feel”, the image change speed must be at least 24 frames / sec. Each box has parameters: width and height. The higher they are, the more pixels are placed in an image, the higher the quality.
Each “point” that makes up a frame has a weight and is equal to 1 byte. Let’s take a Full HD picture and calculate its weight – about two megabytes will be released (1920 x 1080 = 2073 600). So one second of video, containing 24 frames, would weigh 48MB. This is where the concept of bitrate comes in: it is the power to compress a video.
Those. the required file, being encoded, loses weight. But due to strong compression, it may also lose quality. Of course, in reality, not everything is so simple; Much depends on the codec used for encoding. This is the name of the direct compression method. So videos in different formats, but with the same bitrate, can produce images of different quality. The concept of “audio bit rate”, denoting the strength of compression, is also applicable, but for an audio stream.
Bit rate types
Delving into the topic, it is worth noting that the bitrate is not always the same. And now we are not talking about a quantitative indicator, but about a division into types. To work competently with media conversion, read about three types of bitrate: constant, variable, and average, which is a hybrid of the first two.
Constant Bit Rate (CBR)
As the name implies, this type of bit rate does not change during file playback. This compression method allows you to fairly accurately determine the size of the output file and ensure consistent quality throughout your listening or viewing session. But in the entertainment industry, constant bitrate is rarely used due to the impossibility of adjusting it. for dynamic playback, because the files get bigger than they could be.
Variable Bit Rate (VBR)
This type of bit rate is flexible and resistant to change, as a result of which it can be adjusted to the playback object and produce an optimal size / quality indicator. For example, for pictures or musical pieces with a reduced information density, the bit rate will decrease, thus reducing the weight of the object.
Average bit rate
This view is a compromise between the previous ones. The problem with variable bitrate is that changes are automated, and sometimes overcompression can occur. Average bitrate allows the user to set the range in which compression variation will occur. True, the technique of its use is not so simple and is mainly used in professional studios when working on serious projects. An additional advantage of the average bitrate is that it allows you to more accurately calculate the file weight even when the compression force changes.
