Converting mp3 64 to 128 am I getting increased audio fidelity?

vbimport

#1

Hi to all, I am a super newbie to audio and video editing and have been trying to understand the vast amount of information on the topic, but many things are still confusing me. One thing in particular is converting files/compression and downsampling.

I understand that if a file is lossy compressed (like an mp3) it cannot be successfully upsampled to an uncompressed file (like a wav) It must be downsampled from an uncompressed file.

But what I don’t understand is that if I take an mp3 file of 64kbps and convert it to an mp3 again but this time select a higher bit rate, 128 kbps, I noticed the file size increased, but am I really getting more audio fidelity? :confused:

Thanks.


#2

All lossy compression is irreversible, in the sense that any quality loss is permanent.

If you transcode a 64 kbps MP3 file to another MP3 file, the process is lossy and you lose more quality - even if you transcode to a higher bitrate like 128 kbps.

The only way to get quality back is to start from the original source or a lossless copy of that source.


#3

Not quite true. You can convert back to WAV or any format you like, you just won’t gain any quality by doing so.

But what I don’t understand is that if I take an mp3 file of 64kbps and convert it to an mp3 again but this time select a higher bit rate, 128 kbps, I noticed the file size increased, but am I really getting more audio fidelety? :confused:

Thanks.

You won’t get any improvement in quality; the data just isn’t there any more. If you went back to an uncompressed source and resampled at a higher frequency then you will get an improvement.

Basically, with audio and video, it is impossible to get a higher quality than the original source.

Slainte

midders


#4

[QUOTE=DrageMester;2469723]If you transcode a 64 kbps MP3 file to another MP3 file, the process is lossy and you lose more quality - even if you transcode to a higher bitrate like 128 kbps.[/QUOTE]

And I did this, yet when I did it, the file size got bigger. I don’t understand why the file gets bigger if there is less quality, shouldn’t less mean that the file size would get smaller?


#5

[QUOTE=midders;2469724]Not quite true. You can convert back to WAV or any format you like, you just won’t gain any quality by doing so.[/QUOTE]

So if I need to edit the mp3 file and my editor only works with wav files, if I convert to wav, edit the file, then convert back to mp3 do I lose quality that way?


#6

[QUOTE=RustedNailz;2469726]And I did this, yet when I did it, the file size got bigger. I don’t understand why the file gets bigger if there is less quality, shouldn’t less mean that the file size would get smaller?[/QUOTE] The size of a (constant bitrate) MP3 file is determined by the length of the track in minutes:seconds and the bitrate in kbps (kilobits per second).

The actual sound quality can be as good as the bitrate and complexity of music allows, but there’s no lower limit to how bad it can be regardless of bitrate.


#7

[QUOTE=RustedNailz;2469731]So if I need to edit the mp3 file and my editor only works with wav files, if I convert to wav, edit the file, then convert back to mp3 do I lose quality that way?[/QUOTE] Yes you do lose quality that way.


#8

[QUOTE=DrageMester;2469732]Yes you do lose quality that way[/QUOTE]

Thanks so much for responding. The more I learn about this stuff the more confusing it appears to become. I need a book on this :slight_smile:

Going from mp3 to wav to mp3, you said I am still going to lose audio quality, will the loss occur at each transcoding stage?


#9

[QUOTE=RustedNailz;2470052]Going from mp3 to wav to mp3, you said I am still going to lose audio quality, will the loss occur at each transcoding stage?[/QUOTE] No the losses only occurs during lossy encoding, not during lossless encoding nor during decoding.

In other words, decoding MP3 to WAV does not incurr any loss in quality but encoding WAV to MP3 incurs a loss in quality.

Examples of lossless encoders: APE (Monkey’s Audio) and FLAC


#10

[QUOTE=DrageMester;2470058]No the losses only occurs during lossy encoding, not during lossless encoding nor during decoding.

In other words, decoding MP3 to WAV does not incurr any loss in quality but encoding WAV to MP3 incurs a loss in quality.

Examples of lossless encoders: APE (Monkey’s Audio) and FLAC[/QUOTE]

I have heard of FLAC, is it better than WAV?


#11

[QUOTE=RustedNailz;2469731]So if I need to edit the mp3 file and my editor only works with wav files, if I convert to wav, edit the file, then convert back to mp3 do I lose quality that way?[/QUOTE]

You can edit your mp3 without converting it:
Download (free) Audacity (get the Lame encodor for mp3’s) that goes with it & the effects “plug-in” pack (for, eq-ing, compressing, etc…) & you’re set.


#12

[QUOTE=chosenfew777;2471089]You can edit your mp3 without converting it:
Download (free) Audacity (get the Lame encodor for mp3’s) that goes with it & the effects “plug-in” pack (for, eq-ing, compressing, etc…) & you’re set.[/QUOTE]

Thanks for the info, :slight_smile: I have heard of Audacity and that it’s good too. I have not installed it yet because I am going to be getting a video editing program and it will come with it’s own audio editor. (Soundforge) Perhaps it can edit mp3 directly?

If it don’t work, Can I get the Lame encoder and the plug in directly from the Audacity site, and is that what the plug in pack is called (the effects plug in?)


#13


Just remember, as noted above, every time you re-encode/transcode from lossy to lossy, the quality degrades further…So going from 64kbps to 128kbps will [B]not[/B] yield a better quality file, only a bigger one, as you found out…Audacity [I]is[/I] re-encoding the file…


#14

the original content of the mp3 file cannot be improved on fidelity by increasing sample rate.
for a new recording of the file from a better source only will help.
just conversion does not give you any benefit


#15

waste of time…stick with the 64k file…unless your mp3 player wont play them…quality still we be 64k regardless…its like trying to take an xvid/divx file and up-converting it back to standard dvd compliance…damage is already done


#16

[QUOTE=chosenfew777;2471089]You can edit your mp3 without converting it:
Download (free) Audacity (get the Lame encodor for mp3’s) that goes with it & the effects “plug-in” pack (for, eq-ing, compressing, etc…) & you’re set.[/QUOTE]

Actually, as pointed out, using Audacity [I]will[/I] be a re-encoding, with an additional loss of quality. MP3 DirectCut is an editor that allows you to cut, paste and change volume without re-encoding.


#17

[QUOTE=olyteddy;2471116]Actually, as pointed out, using Audacity [I]will[/I] be a re-encoding, with an additional loss of quality. MP3 DirectCut is an editor that allows you to cut, paste and change volume without re-encoding.[/QUOTE]

Thanks, I will check it out.