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Windows => Third Party Plug-ins, Programs, and Skins => Topic started by: KingSparta on January 26, 2004, 04:59:35 pm

Title: Does Anyone Know How Music Is Saved?
Post by: KingSparta on January 26, 2004, 04:59:35 pm

I noticed When Doing A Binary Read Of A MP3 File The Data Is Read In As A Block Of Numbers Like

2146780345 (Max High)

And

-2147465747 (Max Low)

Does Anyone Know?

I am hoping this is an easy way to make\figure a waveform.

Title: Re:Does Anyone Know How Music Is Saved?
Post by: scott_r on January 27, 2004, 02:03:27 am

You can't just take an MP3 and make a waveform... that's what PCM files are for. MP3's are compressed using a few different techniques, so when you look at the compressed data you cant just "see" a waveform. You need to de-compress to a PCM file in order to create a waveform (as far as I'm aware).
Google will provide an endless amount of information about how MP3's are encoded/decoded.

Scott.

ps. Anyone please correct me if i'm wrong :)

Title: Re:Does Anyone Know How Music Is Saved?
Post by: scott_r on January 27, 2004, 02:12:57 am

Here's a document on audio compression that may help:

http://das.iocon.com/res/docs/pdf/Digital_Audio_Compression_01oct1993DTJA03P8.pdf (http://das.iocon.com/res/docs/pdf/Digital_Audio_Compression_01oct1993DTJA03P8.pdf)

Title: Re:Does Anyone Know How Music Is Saved?
Post by: KingSparta on January 27, 2004, 05:40:45 am

Quote

You can't just take an MP3 and make a waveform...

I was figureing it would not be that easy.

I did create a waveform for Wave files, since it is raw data.

the other thing i was looking at was the 4 bytes for the frame i guess they would need to not be included in the wave form.

here is some info on frame headers I saved to my server since i liked the way the pages explained it.

http://www.spartasoft.com/mpeg/index2.htm (http://www.spartasoft.com/mpeg/index2.htm)

Thanks for the info\link now if i can understand it i may play with this Idea i have more, But it looks way over my head.

I have talked to about 10 companies and they said they never thought about this, and they already know how to create wave forms.

weard
 

Title: Re:Does Anyone Know How Music Is Saved?
Post by: scott_r on January 28, 2004, 12:01:56 am

You should be able to find some open source decoders - not sure which language you're using though - to let you pass it the mp3 and have it return a wave for you to manipulate. Probably much easier than writing your own mp3 decoder :)

Scott

ps. The link you posted was very informative... cheers.

Title: Re:Does Anyone Know How Music Is Saved?
Post by: KingSparta on January 28, 2004, 01:05:12 pm

I am trying to find a free mp3 to wave decoder.

wish this was in the SDK.

Maybe i can Ask J River A Question About This, Since MC Has This Why Can't I Just Use J Rivers Decoder.

Title: Re:Does Anyone Know How Music Is Saved?
Post by: KingSparta on January 28, 2004, 08:06:24 pm

Guess that did not work.

Still have not found a free Decoder