I’m running Audacity 2.0.0 on Windows 7 Home Premium (which as far as I know has installed all the latest automated updates)
What I want to do is take all the files from my music folder and change the file type (I want them all to be WMA, and they’re mostly MP3), and also to change the bit-rate if I can. I’ve got the hang of changing the file type, you just save it as a new file type without doing anything to it. But is it possible to change the bit-rate of a file from the original, either raising or lowering it (I’m not sure which I want to do yet, and I may need to do both with the collection as a whole depending on the desired Bit Rate I decide upon)
Audacity does not currently support “batch” exporting WMA format files, so yes it is possible to do with Audacity but not as a batch process. However it is probably not advisable to change the format from MP3 to WMA.
Both MP3 and WMA are “lossy” formats - that is, there is always some loss of sound quality when encoding to a lossy format. Converting from MP3 to WMA requires 2 steps, (1) decoding the MP3, (2) encoding to WMA. Step 2 will reduce the sound quality.
Ahh… well, the inability to batch copy is okay, it just means I’ll have to spend a little more time doing it LOL
The problem I’m having is that I recently bought a SONY Walkman MP3 player with a 14 gigabyte hard drive. The original advert for said MP3 claimed to be able to fit “up to 4,000” songs on the hard drive, but after clearing out all the photos and videos and so on that came with the machine, it has 13.8gb of space free for music. I didn’t delete any of the folders because I wouldn’t have a clue what it was safe to delete. When I uploaded my collection (currently just a bit over 1,800 songs of lengths varying between 2 and 20 minutes, but mostly in the 5 minute range) I managed to fit it all on, but only barely, and there was no room for other songs. Considering that the MP3 was advertised as accepting “up to 4,000 songs”, I thought it was really strange that it should only barely accept less than half of that. I conferred with various people, and they all suggested that MP3 files take up huge amounts of data compared to a WMA file, and I would have taken up even more space by recording lots of songs at a very high Bit Rate
to remedy this situation, I wiped all the music off my computer that I have the CD’s for, and am going to re-record them at a lower bit rate and as WMA files so they’ll take up less data… the problem with that comes with the 500 files or so that I either no longer have the discs for, or never had the files for in the first place (files sent by friends and stuff I recorded myself). Some of this is in WMA format already, but a lot of it is MP3 format, and the bit-rate is all over the place so I’m unsure what to do about that other than use Audacity to change the file type and bit rate if possible… but now I’m concerned about the risk of a huge loss of quality
WMA is probably better for high compression rates than MP3 - that is, if you compress the audio data to a low bit-rate (low quality) then WMA will probably be less bad than MP3. For high quality MP3, WMA, Ogg or AC3 the file size and sound quality are all about the same.
Encoding to a lossy format is always a trade off between sound quality and file size.
For MP3, 128 kbps is generally considered to be the minimum for reasonable quality stereo music. For WMA around 96 kbps is generally considered to be the minimum. For good sound quality you need around 150 kbps (or more) whether MP3, AC3, WMA or OGG.
Not all encoders are equal. The iTunes AC3 encoder is generally considered to be pretty good, and the LAME encoder is good for MP3 (particularly when using VBR).
The damage caused by lossy compression is cumulative - each time the audio is re-encoded the quality gets worse. It’s much better to convert directly from the original CD rip rather than re-encoding something that has already been encoded in a lossy format.
If you want good sound quality I’d recommend that you rip your CDs and encode to MP3 using the “Standard” preset. If you’re happy with lesser sound quality you could try 96 kbps WMA or AC3.
If you decide to re-rip your CDs, C-Dex is a free CD ripper for Windows that supports LAME so you can rip directly to MP3. http://cdexos.sourceforge.net/