Hi,
A couple of music players like WMP and Winamp offers to transcode high bitrate, or unsupported files. Isn't this just to re-encode lossy to even more lossy and thereby getting a significant reduction in quality? One thing is to rip a CD and choose 128 kbps instead of 320, but transcoding a 320 kbps mp3 or wma file down to 128 kbps to make ore music fit on a portable, must be much worse when it comes to quality? Am I missing something here?
Btw, what would the best approach be if you have tons of high quality mp3s and want an many as possible on your portable?
//C
Full Version: Portable players and transcoding.
The quality reduction of many transcodes isn't necessarily what everyone would call significant.
You have to experiment. Like I do.
Sometimes transcoding from MP3 128 to Vorbis -q2 is acceptable. Sometimes transcoding from MP3 192 to Vorbis -q3 is not acceptable.
Of course the best result would be Original directly to whatever format/bitrate you're using.
But if you already have good-enough lossy encoding, sometimes transcoding to something of a lower bitrate will not introduce (too much) audible degradation.
Again, just do it, experiment, and most importantly: do not test for transparency, rather test for acceptability
Sometimes transcoding from MP3 128 to Vorbis -q2 is acceptable. Sometimes transcoding from MP3 192 to Vorbis -q3 is not acceptable.
Of course the best result would be Original directly to whatever format/bitrate you're using.
But if you already have good-enough lossy encoding, sometimes transcoding to something of a lower bitrate will not introduce (too much) audible degradation.
Again, just do it, experiment, and most importantly: do not test for transparency, rather test for acceptability
I've transcoded 320 Kbs mp3's to Lame -v2 and frankly can't ABx between them. And for personal portables, esp. with open-air phones in real-world environments, transcoding to Lame -V5 from source files with bitrates of 256 Kbs and above are acceptable to my ears.
One VERY important point: before transcoding, I always use MP3Gain to reduce the 'max no-clip gain' of the source MP3 file to 0 or less, to avoid encoding unnecessarily clipped signals into the new file.
BobO
One VERY important point: before transcoding, I always use MP3Gain to reduce the 'max no-clip gain' of the source MP3 file to 0 or less, to avoid encoding unnecessarily clipped signals into the new file.
BobO
QUOTE(cdysthe @ Oct 8 2006, 23:45) 
Hi,
A couple of music players like WMP and Winamp offers to transcode high bitrate, or unsupported files. Isn't this just to re-encode lossy to even more lossy and thereby getting a significant reduction in quality? One thing is to rip a CD and choose 128 kbps instead of 320, but transcoding a 320 kbps mp3 or wma file down to 128 kbps to make ore music fit on a portable, must be much worse when it comes to quality? Am I missing something here?
Btw, what would the best approach be if you have tons of high quality mp3s and want an many as possible on your portable?
//C
Theoretically yes, it's better to make any lossy encodings directly from non-lossy source, rather than re-encoding/transcoding from a lossy file to one of a different format or bit rate. If you still have the original uncompressed file or CD, better to encode directly from that.
If one doesn't still have the original uncompressed (or lossless compressed) version, one doesn't really have that choice. And, as some have said, your ears might not be able to tell the difference.
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