Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

2020-08-10 23:04:26

They're just settings I happen to use, as it could be any other similar ones, but just so I can get my head's rather and its bare-bones arithmetic skills around this, whether I use one or another option, I get practically the same bitrate (which for a 16-bit CD track is sometimes within a 1-2kbps difference at most) so I can assume they yield pretty much the same audio quality, right? Or am I wrong?

It's just that I think I got a tad confused regarding the 2 to 23.9 bit per sample range available for the -b option and sort of managed to associate it to the more straightforward (for me) bit rate.

Thanks in advance to anyone clarifying that for me.

Edit: thread title rephrasing and:

I know quality questions are dealt with by ABX testings tracks, but is just happens these are settings I got to after not being able to ABX other similar settings but some 20Kbps lower - so they're way beyond my own personal quantization noise detection threshold, so to speak. And besides, I just want to know if my understanding of Wavpack's bit per sample feature are correct.

Re: Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

Reply #1 – 2020-08-11 13:02:04

I'm surprised you're seeing such a small difference between the two. For CD audio, 3.52 bits per sample is roughly equivalent to 310 kbps. Or, to put it the other way around, CD audio at 400 kbps is about 4.54 bits per sample.

3.52 * (44100 * 2) = 310464
400000 / (44100 * 2) = 4.54

Re: Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

Reply #2 – 2020-08-11 13:17:07

Doh! Only after you said it, did I realize my mistake: I meant 4.52!   (is it only me who's so terrible at coming up with thread titles?)

Anyway, as my question regards the actual workings of the bit-per-sample option, as long as any of those settings match, my (probably silly) question is: 

Bitrates matching, are the final encoding using bits per sample different from when I use bit rate instead?
Does wavpack lossy approach the exact same track differently when using one or another or they're just birds of a feather, in the end and I just got confused about it?

Thanks!

Re: Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

Reply #3 – 2020-08-11 13:19:51

BTW: Once I managed to "master" the easy maths behind converting CD-quality bits per sample to the wavpack scale, but all I remember now is, dividing 1411 by them numbers and nothing else. Gee! I must be really getting thicker! 

Re: Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

Reply #4 – 2020-08-11 13:41:44

According to the WavPack documentation, it uses the same algorithm regardless of how you specify the target rate (in kilobits per second or bits per sample).

Re: Are -b3.52/-b400 practically the same quality, as they have the same bit rate?

Reply #5 – 2020-08-12 10:34:58

Thanks a lot.

After giving the documentation the attention it deserves, I understand that the reasoning behind the bit per sample feature is that quality remains constant for higher resolution audio as well (plus your calculations have helped me remember how I'd gotten to the 4.52 previously mentioned).