5

I am converting audio files of several different formats to mp3 using SoX. According to the docs, you can use the -C argument to specify compression options like the bitrate and quality, the quality being after the decimal point, for example:

sox input.wav -C 128.01 output.mp3 (highest quality, slower)

sox input.wav -C 128.99 output.mp3 (lowest quality, faster)

I expected the second one to sound terrible, however, the audio quality between the two sounds exactly the same. If that is the case, I do not understand why one performs so much slower or what I would gain by setting the compression to higher "quality".

Can someone please tell me if there is a real difference or advantage to using higher quality compression versus lower quality?

P.S. I also checked the file size of each output file and both are exactly the same size. But when hashed, each file comes out with a different hash.

4

2 回答 2

3

参数被传递给 LAME。根据LAME 文档（“算法质量选择”/ 部分-q），质量值对噪声整形和使用的心理声学模型有影响。他们建议质量为 2（即-C 128.2在 SoX 中），说 0 和 1 慢得多，但几乎没有更好。

然而，决定质量的主要因素仍然是比特率。因此，您的情况没有明显差异也就不足为奇了。

于 2013-08-08T22:26:58.707 回答
0

对我来说，简单快速

time sox input.mp3 -C 128 output.mp3

真实 0m7.417s 用户 0m7.334s 系统 0m0.057s

time sox input.mp3 -C 128.02 output.mp3

真实 0m39.805s 用户 0m39.430s 系统 0m0.205s

于 2015-09-09T18:30:46.187 回答