Old 07-14-2016, 02:37 AM   #1
Amether
Human being with feelings
 
Amether's Avatar
 
Join Date: Apr 2006
Location: London
Posts: 519
Default Identifying Transcoded MP3s

I am not a terribly experienced coder but know enough to be able to muddle my way through something if I know it's going to be possible. So my question is if it's possible and is ReaScript (Lua) a good tool for this?

So I want to do a quick FFT on a 320kbps mp3, identify where a steep cutoff is in the spectrum and output a line in an text file the best guess as to its *actual* bitrate.

ie cutoff at 16kHz = 128kbps

It doesn't have to be perfect, just right most of the time. Easy to do on an individual song, however I the intention is to do this to literally hundreds of thousands of songs!

I couldn't find anything out there that does this automatically... any suggestions welcome!

Is it possible with ReaScripts?
Is it better to do with something else?
Amether is offline   Reply With Quote
Old 07-17-2016, 06:13 AM   #2
fernsehmuell
Human being with feelings
 
Join Date: Jun 2016
Location: Wacken
Posts: 15
Default

Hello Amether,

I would recommend a shell script. You could use ffmpeg's highpass filter and measure the loudness with the ebur128 filter. Then create a textfile with the filename/loudness.

regards,
Udo
fernsehmuell is offline   Reply With Quote
Old 06-19-2018, 01:36 PM   #3
Amether
Human being with feelings
 
Amether's Avatar
 
Join Date: Apr 2006
Location: London
Posts: 519
Default

I didn't realise anyone had replied! Thank you. I will try that.
__________________
My name's Martin ... phone ... Martin Phone! http://soundcloud.com/martin-phone
Amether is offline   Reply With Quote
Old 11-09-2020, 12:40 PM   #4
Amether
Human being with feelings
 
Amether's Avatar
 
Join Date: Apr 2006
Location: London
Posts: 519
Default

Oh hello. I did actually do this and am returning to it no lockdown makes work a bit quieter... and it's vaguely successful. Doing this with older songs (50s, 60s) or maybe a piano solo, it gets a little confused. I do often seem to be getting *something* when I measure the EBUR128 on something high-pass filtered at 17000.

I realised I was checking my results by dropping the mp3s into Reaper and having a quick look at the spectral display. Even on a VBR mp3 of a song from the 50s there is a very sharp, defined line above which you get NO material. Quite simply, how comes I'm not getting that? Is it a dynamic threshold of sorts?
__________________
My name's Martin ... phone ... Martin Phone! http://soundcloud.com/martin-phone
Amether is offline   Reply With Quote
Old 11-09-2020, 02:54 PM   #5
junh1024
Human being with feelings
 
Join Date: Feb 2014
Posts: 240
Default

See the compare section https://fakinthefunk.net/en/#compare
__________________
REAPER 2D/3D Surround suite: Instructions & Download | Discussion | Donate
junh1024 is offline   Reply With Quote
Old 11-10-2020, 05:44 AM   #6
Amether
Human being with feelings
 
Amether's Avatar
 
Join Date: Apr 2006
Location: London
Posts: 519
Default

Ah, ha. Yes. This is actually pretty good. Far more efficient than mine, but it has trouble with the same songs as I was having. Actually fairly reassuring but for testing 100000s of songs, this is a great solution. Thanks.
__________________
My name's Martin ... phone ... Martin Phone! http://soundcloud.com/martin-phone
Amether is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 11:06 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.