Good, thanks for the info. I never really found the time or the need
to go chasing up on the info, but its nice to know how their algorithms compare.
Cheers, Daniel.
On Tue, 6 Apr 2004 11:10:10 +0100, Dave Cross <dave@xxxxxxxxxxx> wrote:
On Tue, Apr 06, 2004 at 07:44:41PM +1000, Daniel Stonier wrote:
I just had a look at the script itself and that is how it works. Still, how much information does this lose? I have no idea - you would have to have a look at the algorithms for mp3 and ogg to work out what each captures and loses. It may still be in the transfer there is little loss to get worried about (the mp3 to wav product may just be exactly what ogg captures anyway). I'd be interested in hearing from anyone who might know.
The Ogg Vorbis people would probably know. From their FAQ:
Can I convert my MP3 collection to the Ogg Vorbis format?
You can convert any audio format to Ogg Vorbis. However, converting from one lossy format, like MP3, to another lossy format, like Vorbis, is generally a bad idea. Both MP3 and Vorbis encoders achieve high compression ratios by throwing away parts of the audio waveform that you probably won't hear. However, the MP3 and Vorbis codecs are very different, so they each will throw away different parts of the audio, although there certainly is some overlap. Converting a MP3 to Vorbis involves decoding the MP3 file back to an uncompressed format, like WAV, and recompressing it using the Ogg Vorbis encoder. The decoded MP3 will be missing the parts of the original audio that the MP3 encoder chose to discard. The Ogg Vorbis encoder will then discard other audio components when it compresses the data. At best, the result will be an Ogg file that sounds the same as your original MP3, but it is most likely that the resulting file will sound worse than your original MP3. In no case will you get a file that sounds better than the original MP3.
Since many music players can play both MP3 and Ogg files, there is no reason that you should have to switch all of your files to one format or the other. If you like Ogg Vorbis, then we would encourage you to use it when you encode from original, lossless audio sources (like CDs). When encoding from originals, you will find that you can make Ogg files that are smaller or of better quality (or both) than your MP3s.
http://www.vorbis.com/faq.psp#transcode
At any rate, I couldn't come across a file where I could distinguish between one or the other by ear which was the only test that needed to satisfy me. I only converted a dozen or so files of some music that I had from a group whose music I can't get in oz though - the rest I ripped straight from my CD's to ogg format, so I haven't really tried it out thoroughly.
That may be a limitation of the equipment you are using.
Dave...
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