convert mp3 into wav (PCM) 16 Bit 44,1 kHz - does it leave traces?

[pur123456789]

Hi, a system where we want to upload something says that the server does not accept mp3, or wav files being produced out of mp3/being converted from mp3 files. Still, in most cases we only have the mp3 files. So I thought that if I take the mp3 file, open it in Adobe Audition and then export it into the right format, that should be fine. I mean, it is a prefessional program and not just a simple converter. Do you see problems here? It is important as the aggregator also delivers Itunes and I want to avoid technical problems. The system where we want to upload says that their server does not accept files originally made of mp3. Hmm. Hope you can help. Best regards

[Bob_Howes · Accepted solution]

Audition's conversion from MP3 to Wave will give you all the quality present in the MP3--but it can't and doesn't make it any better and any MP3 artefacts will still be present.  Most noticeable to your client will be the fact that the frequency response usually cuts off sharply at around 16k...and, depending on how the original MP3 was created and what bit rate is used, there may be artefacts that a good set of ears can hear.  However, once you have the file in wave format, you can use any Audition processes as you would normally without problems. 

One thing to watch though:  if you ever have to re-save the file to MP3 again, it's an additional lossy compression process and a few more artefacts will be created.  As the effects are cumulative, after a few re-compressions (if that's a word) the quality will fall off the edge of a cliff.

Anyway, to get back to your original question, the fact that your file started life as MP3 COULD be detected by your end user if they're checking carefully.  It depends how tightly they enforce their rule.

[pur123456789]

Ok, so if I get you right, then as long as the system accepts the uploading process, it should work. Because this is what they say: The server does not accept...?

Guess I have to try. Thank you for the information! E.g. did not know that reconverting into mp3 meant additinal loss of quality..

Best regards!

[SteveG_AudioMasters_]

pur123456789  wrote

The system where we want to upload says that their server does not accept files originally made of mp3.

I'm not quite sure how it can tell, actually - but you should probably make sure, if you open it in Audition, that the metadata is clean before you save it...

The problem (if you can call it that) with MP3 as a format is that if you want to do almost anything at all with it after it's made except play it, you have to decode it first - you can't work on it as an MP3. The ever-so-slight exceptions to this are that you can make a very crude alteration to the volume, and it's also possible to shorten them. But that's it - and any attempt to store anything you do (having decoded it) requires that it is re-encoded. Every encoding process requires what's known as a 'coding gain' - and what tends to happen is that since the redundant stuff in the file was already previously removed, it finds something else to have a go at - so the quality inevitably drops considerably, as it's a masking process that takes place. In detail, what happens is that anything that the encoder considers to be 'hidden detail' is encoded at a much lower bit rate - that's where the coding gain comes from.