[xicex]

Will a 128kbps MP3 transcoded from a 320kbps mp3 will have better sound quality than a 128kbps MP3 transcoded from a 192kbps mp3?

 

[backtoreality15]

Quote:

Originally Posted by xicex /img/forum/go_quote.gif Will a 128kbps MP3 transcoded from a 320kbps mp3 will have better sound quality than a 128kbps MP3 transcoded from a 192kbps mp3?

Yes, that tends to be the case. Encoding a MP3 from another MP3 (or any other lossy format) quickly leads to deterioration of quality. You want your master to have the highest quality possible (AKA lossless).

 

[krmathis]

Yes, most probably.
As less audio data were thrown away encoding to 320kbps than 192kbps, and hence it is a "better" source.

 

[nick_charles]

Quote:

Originally Posted by xicex /img/forum/go_quote.gif Will a 128kbps MP3 transcoded from a 320kbps mp3 will have better sound quality than a 128kbps MP3 transcoded from a 192kbps mp3?

NO.


Both files will be 128K having about 1/9th of the uncompressed audio data, neither will have anything much above 16K. The 320 to 128 conversion will just throw away more data than the 192 to 128 conversion. Try a blind test to confirm this though.

 

[m1abrams]

Quote:

Originally Posted by nick_charles /img/forum/go_quote.gif NO. Both files will be 128K having about 1/9th of the uncompressed audio data, neither will have anything much above 16K. The 320 to 128 conversion will just throw away more data than the 192 to 128 conversion. Try a blind test to confirm this though.

On a purely techinical standpoint you are wrong. While you most likely will not be able to tell the difference in a blind test, both 128K files will sound bad but in different ways.

Because you have LESS data with the 192 than the 320 you will have less accurate data to determine what should be kept and what should not. It is not a simple matter of just dropping down to different levels.

Based on your answer you should see no difference if the source file was lossless but we know that is not true. You will notice a difference transcoding from lossy->lossy versus lossless->lossy.

 

[astroid]

Simple , the higher bitrate the original file is, the better any transcode from it can be.

 

[royalcrown]

Nick: I am not familiar with lossy audio compression algorithms in any formal sense. Could I infer from your answer that regardless of the source quality (so long as the source quality is higher than the resultant file's quality), two mp3's with the same bitrate will sound the same?

Basically what I'm getting at: would a transcode from, say, 320k to 192k sound the same as a transcode from FLAC or WAV or whatever down to 192k?

 

[m1abrams]

Quote:

Originally Posted by royalcrown /img/forum/go_quote.gif Nick: I am not familiar with lossy audio compression algorithms in any formal sense. Could I infer from your answer that regardless of the source quality (so long as the source quality is higher than the resultant file's quality), two mp3's with the same bitrate will sound the same? Basically what I'm getting at: would a transcode from, say, 320k to 192k sound the same as a transcode from FLAC or WAV or whatever down to 192k?

I am not Nick, however I can answer your question. No. A transcode from 192K to 128K would not sound the same as a transcode from FLAC to 128K which is why I posted in disagreement to Nick.

 

[iriverdude]

The question is why would you transcode one lossy format to another lossy format, especially from same codec, just to a lower bitrate?

Quote:

, 320k to 192k sound the same as a transcode from FLAC or WAV or whatever down to 192k?

No, the flac-mp3 encode will sound better than mp3-mp3.

 

[backtoreality15]

Quote:

Originally Posted by iriverdude /img/forum/go_quote.gif The question is why would you transcode one lossy format to another lossy format, especially from same codec, just to a lower bitrate? No, the flac-mp3 encode will sound better than mp3-mp3.

I'd assume that's if you don't have enough space to put many songs of that bitrate onto a portable player? Not everyone has original CDs

haha

 

[royalcrown]

m1abrams+iriverdude: thanks for the response. The question was moreso along the lines of "does 192-128 sound the same as 320-128 because the bitrate is so low that we just can't distinguish details, or is that because of some mechanism within LAME or any other mp3 encoder?" At any rate the question was merely out of curiosity.

 

[leeperry]

well, why don't you measure it w/ WaveSpectra? you'll have distortion figures to look at

http://www.head-fi.org/forums/5785853-post42.html