I have this titanic task to do: I would like to run evaluation through all of my files and see, what is the real quality of them
I know there is BITRATE tag field in Mp3tag available under information fields sub-menu, but this gives only the supposed quality. [There also is the CODEC tag field, but that gives only info about codec used for creation of the file]. And it is useless for me because all of my MP3's at some point had same makeover done on them [after which they were encoded into 320 MP3]
But recently I got acquainted with the function of spectrogram in Audacity: by using it I can see if for example a FLAC file really have all those sounds not present MP3 files or if someone only encoded sound of lesser quality into a higher quality format. Unfortunately, right now I do this by hand, one file at a time; and it takes a lot of clicking every single time; and on top of that I also don't know how to export info about the real quality into a tag field
And as the difference between maxed out 320 MP3 and a FLAC is undetectable for me, a difference between 192-256 and 320 MP3 is. So If would want to replace the lesser ones with something better [320 or FLAC]; but in order to do that effectively / systematically, I would first need to single them out [and create some kind of a work schedule]
So the question is: what can I use [to do this in a kind of an automatic way]?
I've already googled this topic to some extent, coming out with the aforementioned Audicity software [and some other pieces of software which didn't stay too long in my system]. Maybe someone here already did the same thing with his / hers files? Or know what could I try out?
Perhaps you can run a test with WinMp3Packer and convert CBR files to VBR with a low VBR-setting in WinMP3Packer.
The lower the effecting VBR is, the lower was the quality, I would guess.
It seems, that you are on the way to find out the golden formula for the term "quality", which delivers a universally compatible concrete value.
Try out the SoX and SoXI command line utilities at ... http://sox.sourceforge.net
Beside many other audio related functions SoX can create a spectrogram as a png file.
For the first view there are PDF help files from the SoX package ... sox_14_4_2.pdf.rar (183 KB)
DD.20151117.1047.CET
Creating info in a graphical form wold not do me any good. We are talking bout 15 00 files. I would need an info in form of a tag, that I could easily see in a column in Mptag; I would mark them as "very good", "good enough", "not acceptable", with a simple one sign code [like "+", "0", "-"]
So for now I use my ears
It has come to my attention in recent months, that some types of music / sounds are more prone to audible damage done by file compression. Like for example an opera signing still can be enjoyable; or some bass guitar and keyboards layed upon them. But a full symphonic orchestra sounds like heard from behind a wall. Or high hat sounds just distorted bad. So for now when I hear something low quality I send it to the Audacity
And in something like 9 out 10 cases I am correct in my estimates; which means if I hear a bad quality then in the spectrogram I can see a proof of that. But that takes way too much time and totally disrupts my workflow