How and where to compress audio?

[Kawatta-kun]

I have MP3 sources and want them to become WAV so I can edit them. In what free program can I be able to compress them that way?

And directly from the NLE, which is better, or it is good to:
- Render MP3 as WAV and edit with it?;
- leave the MP3 there and at final render is PCM uncompressed?

Thank you.

[post-it]

the MP3 is a poor substitute for the actual CD soundtrack and editing it in a .wav form
will only expose that error even more!

if any program could do it, it would be jetAudio v8.0.11

your video editor would prefer things in .WAV and .AVI forms.

Once you are done with your editing, re-compress it with Zarx264 program
and "your you'll be able to share it with anybody who wants it."

[Kawatta-kun]

Sooo without converting it to WAV, cause clearly it wouldn't be the best option, what could I do??
I guess just editing normaly, then rendering it UTvideo/PCM uncompressed.

[Qyot27]

If you're working from MP3, and not doing anything to the audio in the video editing program, then decode it to a regular PCM Wave file (this can be done using any number of tools - lame or a frontend for it is a good option), edit using the Wave file, export the video without audio, compress the video, and then mux the original MP3 back into the final copy. That way no recompression occurs. If you have to edit down the audio, then still decode to PCM Wave, edit the audio in Audacity or something, keep it as PCM, edit the video with that new PCM file, export without audio, and then use the PCM file you edited with to encode an MP3 or AAC file and mux that with the final video encode.

The same is generally true of instances using PCM from the get-go where the video editing program needs the 24fps speedup method because it can't properly handle 23.976fps (like older versions of Premiere). Except in this case you create a new file that's been pitchshifted, edit with that, and perform the fixes on the video before using the original unshifted PCM file to compress the audio to whatever format you need.