ncm format is the download format used by NetEase Cloud Music. It needs to be played within the membership period. Music in this format cannot be used on many software. If it can be converted to Mp3 format music, it can be played on Convenient to use everywhere.
#The operating environment of this tutorial: Windows 10 system, Dell G3 computer.
What is the format of ncm?
ncm format is the download format used by NetEase Cloud Music. It needs to be played within the membership period. Music in this format cannot be used on many software. If it can be converted to Mp3 format music, Can be used conveniently everywhere.
Related expansion:
The music we usually talk about in mp3 format and wav format is actually a compression encoding format.
How does a song come from the singer's throat and become a file?
It needs to go through three steps of sampling, quantization and encoding.
Sampling
Sound is a continuous analog signal. Through sampling, it is converted into a discrete digital signal. What must be followed is the Nyquist theorem: as long as the sampling frequency is not lower than the sound At twice the highest frequency of the signal, the sampled digital signal can record and restore the sound with fidelity.
The range that the human ear can hear is 20Hz to 20kHz, so the sampling frequency is generally 44.1kHz. This ensures that the sampled sound can be digitized up to 20kHz, so that after digitization, the human ear can hear The sound quality will not be reduced. The so-called 44.1kHz means 44,100 samples per second.
Quantization
Quantization refers to digitizing the signal on the amplitude axis, that is, how many bits of data are used to record a sample. For example, a 16-bit binary signal is used to represent a sample of sound, and the range represented by 16 bits (a short) is [-32768, 32767], with a total of 65536 possible values, so the final simulated audio signal is also different in amplitude. Divided into 65536 layers
Encoding
Encoding means that we record the sampled and quantized digital data in a certain format. If stored directly, the file may be too large. There is no problem if it is stored directly like a CD, but if it is to be transmitted online on the network, it must be compressed.
The principle of compression is to compress redundant signals, including signals that are imperceptible to the human ear and signals masked by the human ear masking effect (which means that the human ear is only sensitive to the most obvious sound responses). Simultaneous compression algorithms include lossy compression and lossless compression. Lossless compression means that the decompressed data can be completely restored. Lossy compression means that the decompressed data cannot be completely restored and some information will be lost.
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