Several small concepts that multimedia needs to understand

There have been some days of contact with multimedia, and I think there are several important concepts, such as sampling frequency, quantization progress, bit rate (bit rate ), it is possible that the meaning of the content will be mixed during initial contact.

1> sampling frequency: the number of samples to be extracted from the signal per second. Generally, we can obtain the sampling frequency from the format in multimedia files, in Hz, most of the familiar audio MP3 audio samples are sampled at 44100Hz.

2> after sampling with Quantization precision, data must be quantified. The number of digits of each sample is clearly indicated in the unit bit per sample (BPS). Generally, the quantization precision is 16 bit.

3> the bit rate (bit rate, bit rate) data traffic used by audio and video files per second can be clearly obtained through formula calculation:

Bit Rate = sampling frequency * quantization progress = sample/S * bit/sample = bit/s

Byte rate = bit rate/8 = bit/8/S = byte/s

Generally, the video stream rate is very high, especially the number of megabytes that can be reached per second for HD videos.

4> estimate the total file duration

Total duration = total file length/byte rate = byte/(byte/S) = s