compare MP3's - Printable Version
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compare MP3's by CookieRevised on 04-05-2004 at 10:43 AM
lo,
Wanna ask if someone knows a quality program that can compare MP3's.
What I want to do is to compare only the decoded audio stream. So differences in the ID-tags (how exothic they might be) must be ignored.
It would be perfect if the program also can produce the differences in a graphical way (specograph), so I can see where exactly the differences are...
On the same subject, I'm also seeking a program that can edit all ID-tags and read other parameters/info (like encoding, (variable) bitrates, etc...) within an MP3.
Also... does someone have the specs of the MP3-file format? (I can google this, but more sources means, I have more certainty that the specs are correct and complete)
RE: compare MP3's by Choli on 04-05-2004 at 11:16 AM
quote:what about Sound Forge?
Originally posted by CookieRevised
On the same subject, I'm also seeking a program that can edit all ID-tags and read other parameters/info (like encoding, (variable) bitrates, etc...) within an MP3.
quote:are they public? don't you have to pay for them? or was it when you wanted to do a program that encodes in mp3?
Originally posted by CookieRevised
Also... does someone have the specs of the MP3-file format?
quote:that's quite difficult, because 2 decoded auido strams may be diferent and you'll hear the same. what you're looking for should do a frequency analisys and show results... quite complex software...
Originally posted by CookieRevised
What I want to do is to compare only the decoded audio stream.
If what you want to compare are 2 wav (for example) files compressed in mp3 with diferent parameters (bitrate, quality, ....) maybe you can do this:
Open the files (MP3s) in soundforge and "substract" the files. You can do this inverting one file, copying it and pasting (with mixing) on the other. now listen to the result and hear the diferences yourself. (soundforge can show specographs, i think).
This way is a bit dodgy but maybe you get what you want. I'm not sure, I never did that.
RE: RE: compare MP3's by CookieRevised on 04-05-2004 at 11:49 AM
quote:Didn't think of that... thanks... I'll try...
Originally posted by Choli
quote:what about Sound Forge?
Originally posted by CookieRevised
On the same subject, I'm also seeking a program that can edit all ID-tags and read other parameters/info (like encoding, (variable) bitrates, etc...) within an MP3.
quote:I'm not looking for the MPEG-3 encoding itself, but the fileformat of the MP3. I dunno if the MPEG-3 encoding is public or not, but the MP3 fileformat must certainly be documented very clearly somewhere... (an analogy to the GIF-fileformat as example of what I mean: I'm looking for the physical buildup of the fileformat, but not the LZW-compression which can be used by GIF)
Originally posted by Choli
quote:are they public? don't you have to pay for them? or was it when you wanted to do a program that encodes in mp3?
Originally posted by CookieRevised
Also... does someone have the specs of the MP3-file format?
quote:yeah... and that's exactly what I want
Originally posted by Choli
quote:that's quite difficult, because 2 decoded auido strams may be diferent and you'll hear the same. what you're looking for should do a frequency analisys and show results... quite complex software...
Originally posted by CookieRevised
What I want to do is to compare only the decoded audio stream.
quote:Not useable for what I want right now, but I'll keep this "trick" in mind... thanks...
Originally posted by Choli
If what you want to compare are 2 wav (for example) files compressed in mp3 with diferent parameters (bitrate, quality, ....) maybe you can do this:
Open the files (MP3s) in soundforge and "substract" the files. You can do this inverting one file, copying it and pasting (with mixing) on the other. now listen to the result and hear the diferences yourself. (soundforge can show specographs, i think).
This way is a bit dodgy but maybe you get what you want. I'm not sure, I never did that.
RE: RE: RE: compare MP3's by sock on 04-06-2004 at 02:55 AM
It's time to be picky again! 
quote:MP3 is based on MPEG Audio Layer 3 encoding - that is, MPEG1, not to be mixed with later revisions of the MPEG standard. As far as I know, MPEG3 was aborted and never used in the big world... So there's just MPEG, MPEG2 (used in DVDs) and MPEG4. MP3 is a part of the original MPEG specification.
Originally posted by CookieRevised
I'm not looking for the MPEG-3 encoding itself, but the fileformat of the MP3. I dunno if the MPEG-3 encoding is public or not, but the MP3 fileformat must certainly be documented very clearly somewhere... (an analogy to the GIF-fileformat as example of what I mean: I'm looking for the physical buildup of the fileformat, but not the LZW-compression which can be used by GIF)
As to your question, I really have no idea. MP3 is a proprietary format that belongs to the German Fraunhofer IIS. It's not an open format like Ogg. I don't think if you're even allowed to encode audio without a license... So I guess you'll have to google it hard.
RE: compare MP3's by CookieRevised on 04-06-2004 at 03:26 AM
hehehe... 
Anyways, I don't need the (licensed) encoding/decoding itself (avoiding the name mpeg/mp3/whatever here otherwise I'll make a mistake again ) I needed the fileformat: where are the tags stored, what are the first bytes indicating, etc... etc...
=> found plenty of info on sites like http://www.wotsit.org/, http://www.filespecs.com/, ...
On the other part, I needed a program that could compare the uncompressed audio streams of two mp3-files easly (without converting the mp3 first to a PCM, then comparing those PCM's, etc... etc...) (<= dont say I use the term wrong again )
=> still didn't try out SoundForge, so I dunno...
EDIT: by this time I've indeed found plenty of info about the MPEG audio format and everything I need (including the official licensed papers)...