Audio Bitrate Calculation
Generally, the files we read will know the following parameters:
Sampling frequency: the number of sampling points that pass one second; by
For example, the most common sample rate of 44.1k means that there are 44,100 sampled data points in one second;
Bit depth: Bit depth is also called sampling bit depth, and the bit depth of the audio determines the dynamic range.
Our common 16-bit (16-bit) can record a dynamic range of about 96 decibels. Well, roughly you can know that each bit can record about 6 decibels of sound. Similarly, the 20-bit recordable dynamic range is about 120 dB; 24 bits is about 144 dB.
If we define 0dB as the maximum value, then the amplitude of the sound is calculated by extending down, then the dynamic range of CD audio is “-96dB ~ 0dB”. And so on, the dynamic range of 24-bit HD-Audio is “-144dB~0dB”. It can be seen that at higher bit depths, a greater dynamic range is available and lower levels of detail can be recorded.
Number of channels: usually single channel or two channels
Through the above parameters, the bit rate of the audio can be calculated
\color{blue}{code rate = sample rate (44.1k) * bit depth (16) * number of channels (2) = 1411.2kbps}
Audio bitrate, also known as bitrate: Refers to the amount of data that can pass through an audio stream per second. For example, 128 kbps, where ps (per second) is per second and kb is thousand bits, then 128 kbps means that the amount of data that can be transmitted in one second is 128 thousand bits. For files of the same format, the higher the bitrate, the better the sound quality. But for audio files of different formats, the same bitrate does not mean the same sound quality.
CD quality sound, usually two channels, compressed at 128kbps MP3, one second of data is converted to 128kbits. Some details are lost, which saves a lot of disk space or bandwidth.
After knowing the audio code rate, you can get the size of the whole audio file = duration (300s) * code rate (1411.2)/1024/8=51.67M
