Bitrate question

ok, i have a bunch of 128 kb/s mp3 files. i burned them on cd audio. then i copied those songs from this burned cd audio to my hard drive as a 128kb/s mp3 files. question is: is there a difference between quality of tracks i copied as 128 kb/s from burned cd audio on my hard drive and 128 kbs tracks which i used to burn the same cd audio?

If I understood right, you burned an audio CD from your mp3 files, and not a data CD containing all those mp3 as files. Then you got this audio CD and ripped it back to mp3 data files. If this is correct, then yes there is a difference.

Whenever you encode from an audio CD to mp3, there is some information loss, this is the reason why mp3 is a lossy compression scheme. What you did is actually encoding two times to mp3. Certainly there is a degradation in quality. I don’t know if this is audible or not, but this greatly depends on the equipment, kind of music, “sensitive” ears :slight_smile: etc…

Do you have your initial mp3 files? If so, use these…

[QUOTE=piach;2227602]ok, i have a bunch of 128 kb/s mp3 files. i burned them on cd audio. then i copied those songs from this burned cd audio to my hard drive as a 128kb/s mp3 files. question is: is there a difference between quality of tracks i copied as 128 kb/s from burned cd audio on my hard drive and 128 kbs tracks which i used to burn the same cd audio?[/QUOTE]

If you copy to hard drive as you specify, than files on hard drive will be exactly the same. You are not encoding, just making copy of the same file.
Unless you burned them on CD in wav format and than back to hard drive as mp3 from there.

hmm as far as i know the original copy of an audio cd has 1400kb/s. i though that the degradation is happening during the encoding from an audio cd (1400) to a mp3 (128), then i burned those (128) on audio cd (the burned audio cd is now 128 kb/s, not 1400 , right?). then encoded from 128 kbs audio cd to 128 kbs mp3’s and i thought that there’s no loss.

1st step: rip from .cda/.wav ~1400 kbps full-quality source. The audio begins as “clean”, with all audio data intact for full sound quality, but you then encode. Encoding from a lossless to lossy format, results in loss of audio information, and to MP3 with 128 kbps results in a lot of data being lost.

2nd step: burn new MP3 files of 128 kbps [lossy] to a CD with ~1400 kbps bitrate. Now, while the bitrate has gone up, and we have gone from lossy to lossless, the data from the original CD that was lost while encoding HAS been lost and will not be recovered by even the best MP3 decoder. Your CD sounds exactly like the lossy MP3s you made the first time.

3rd step: rip from an audio CD that SOUNDS as bad as a 128 kbps MP3 file but has a “physical” bitrate of ~1400 kbps, to another 128 kbps MP3 file. If the encoder is good, it will be able to do an efficient encoding job and closely match the original MP3. However, more audio information will still be lost in the compression, because no MP3 encoder [that I know of] will discard the same information twice. Thus, this second ripping to MP3 causes more of the original data to be lost; so the files [I]may still be the same physical size and quality[/I] [in relation to the bitrate], but the quality of the audio [I]as you hear[/I] it is worse than the original MP3.

The issue is not just going between bitrates, but going between a lossy and lossless format.

[QUOTE=piach;2227602]ok,[B] i have a bunch of 128 kb/s mp3 files. i burned them on cd audio. [/B]then i copied those songs from this burned cd audio to my hard drive as a 128kb/s mp3 files. question is: is there a difference between quality of tracks i copied as 128 kb/s from burned cd audio on my hard drive and 128 kbs tracks which i used to burn the same cd audio?[/QUOTE]
Yes there will be a difference. Once burned as an audio CD the only way to convert again to mp3 from that CD, and maintain most of the quality, would be to make 320kb/s mp3’s.

so, what is better quality. encoded mp3 from the original 1400kbs as 96 kbs mp3’s, or from the burned with 128kbs mp3’s as 128 kbs mp3’s.

I do not want to be rude, but [B]Albert[/B] explained the process in detail. Just re read his post and make conclusion on what exactly you are doing from there.
To your last post
Original conversion from 1400 wav to 96 mp3 will be worse than recorded copy of 128 mp3 to hard drive.