Quote:
Originally Posted by Asathor
I'm assuming I've mis-read your meaning above -- are you saying that you can take a 128 kbps mp3 file - and somehow convert that all the way up to a 320 kbps file? If so - then I believe you're unclear about the basic principles of lossy audio compression. All you've done by transcoding from the lower bit-rate is increase file size - but you can't re-introduce frequencies that have already been removed by the initial encoding.
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Yes, by all means you should avoid transcoding (= decoding an MP3 and re-encoding it into something else). Transcoding a low-bitrate file into a higher bitrate will in the best case preserve all the artefacts of the low bitrate, but in most cases it will only make it sound worse. You can't just recreate the information that was thrown away while encoding at low bitrate!!! Transcoding a high-bitrate file to a lower-bitrate file is also bad, because it will cause more distortion than if you had directly encoded the original material into the lower bitrate. You can do it, but you'd need to use a higher bitrate than your 'target rate' to compensate for the extra distortion.
Of course, transcoding is exactly what Allofmp3 does with the Online Encoding feature. But when starting from 384kbps material as they do, the artefacts are so small that transcoding is perfectly acceptable. Of course, if you have the choice between OE and OEX, you should go for OEX.
I personally download in Ogg format, at quality setting 5 for 'average' songs, and 6 for the songs I really like.