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technology » spectral analysis of audio files

dannyp's avatar
15 years ago
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dannyp
dʎuuɐp
I used Audio Identifier to check the quality of my tracks briefly. It's pretty quick to look through all your albums.

Does anyone know how to determine the quality visually like when the spectral images are posted? Seems overboard but I'm interested in how it's done.

I'm happy to report only one of my albums is a terrible encoding according to Audio Identifier!
lucas's avatar
15 years ago
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lucas
i ❤ demo
i bet nestor has srs knowledge to drop. i'm sure you can find info on waffles.fm and what.cd as well.
dannyp's avatar
15 years ago
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dannyp
dʎuuɐp
i searched around on waffles, there isn't too much info on it. i just punched some stuff into what and there's more stuff coming up it seems.

here's the one album with really shitty results in my collection
https://www.waffles.fm/details.php?id=87199

http://i40.tinypic.com/29prdee.jpg
lucas's avatar
15 years ago
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lucas
i ❤ demo
did you report the torrent? if you don't want to, i will. :)
dannyp's avatar
15 years ago
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dannyp
dʎuuɐp
I'm skeptical about this application. It seems like it grabs the minimum bitrate that the track drops to. What rule would I cite if I reported it?

Can an encode with a bitrate of below 192 kbps be uploaded?

All music uploads must have an AVERAGE or CONSTANT bitrate of at least 192kbps, regardless of format/source.
The only exceptions:

1. MP3 encodes using V0 or V2 VBR presets which dip below 192kbps average bitrate.


It's V0 and it seems to conform to the rules, but the way the program highlights and identifies quality might be buggy with variable bit rate.
lucas's avatar
15 years ago
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lucas
i ❤ demo
dunno, i already reported it. we'll see what happens to it.
nestor's avatar
15 years ago
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nestor
nestor
If you want to check for a transcode, generate a spectral and look for a 'hard cutoff' or 'blockiness' well below 20khz. 128 often cuts at 16khz or below. V0 should lowpass above 18 or 19.

hope that helps :)
dannyp's avatar
15 years ago
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dannyp
dʎuuɐp
> we'll see what happens to it.

that shit is /gone/

:D