The ratio between frequency, bit rate, bit rate and sound quality of MP3 Part 3
First I took the track with RAC, and then I used the MP3 LAME encoder (VISION 1.92 Motor 3.92) engine in the CD’EX software to process the WAV file. I tried the parameters lick one by one to choose a good effect:
The first thread priority parameter selects the highest and the lowest respectively. When other parameters are equal, the comparison is compressed. It is found that the degree of thread priority has no effect on sound. The size of the files generated is the same. , and the comparison sounds the same, so this parameter has no effect on sound quality.
The second parameter is the version, which can be selected from MPEGI, MPEGII and MPEGII.V. The same, other parameters are determined and these three options are used to compress three times. The size is the same, but MPEGI’s real listening direction is better. The medium-low frequency compression ratio is a bit smaller, but high frequency distortion is a bit more. It is more suitable for listening to human voice and pop music. For classical music, use the MPEGI type. It is not bad, the sound is better, but if it is solo music with many medium and high frequencies such as the violin, it is recommended to use the MPEGII.V type, which will have better results.
The third parameter is the most important, which is the bit rate. Choosing it directly affects the size and auditory experience of its MP3 file. The greater the compression ratio, the greater the distortion, and the lower the compression ratio, the minor is distortion, but how can we find a us? What is the balance that is acceptable for both parties? This requires careful exploration in the experiment. Taking into account that the sound quality of the files with a low bit rate is not suitable for playing music, the minimum assembly is 128 kbps, and four fixed bit rate of 128, 192, 256 and 320 are used For comparison and test.
The compression ratio of 128 kbps remains relatively approximate, and the high frequency part is very distorted after compression. It sounds hollow, wrinkled, rough and, often, blinking. Mally understood, the compressed volume of a musical piece at 3 minutes 39 is 3414 kb. Although the volume is not great, the sound is not pleasant and there is a great flaw.
The compression effect of the Bits rate of 192 Kbps is much better than that of 128. First, the sound is solid, at least there is no vacuum sensation, high frequency distortion is also much lower, sound is compact, the noise is small and clean, which is ideal for contrast. The listening effect is only because the compression is still relatively strong, the performance of the details is not very good, the texture of musical instruments, especially the Wind instruments, it is still very hard. , unreal and lacks musicality. The compressed size is 5123 KB, I think this compression ratio is better to use in an MP3 player with a capacity of 128 ~ 256 m, which can not only meet the main sense of hearing, but is also suitable for size 128m You can store about 95 minutes of music, and 256m can duplicate 190 minutes of music.
