General discussion

Need to down size MP3 to lower bit rate

Oct 24, 2010 4:28PM PDT

I have a massive audio book collection converted at 128kbps and this is still too large: Is there a program that can re-sample to a lower rate of 64kbps or even hopefully 32kbps? I can't re-rip, because I no longer have the CDs. This must be a MP3 to MP3 exchange.

I had originally used WMP11 and 128 is the lowest, I tried Audacity but I was unhappy with the sampling (there was a faint and annoying "pop" every eight seconds or so).

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Don't do it.
Oct 29, 2010 2:29AM PDT

With 1TB drives at 49 bucks and 2TB drives about to drop under 100 there is no reason to do this.

Let the technology catch up and cure this.

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Thanks for nothing
Nov 9, 2010 8:05PM PST

Well, that was absolutely NO help what so ever. Why even bother with a response when you don?t even come close to answering the question.

I am looking for a way to downsize MP3s by lowering the bit rate. This is something that can easily be done with video, but I am finding it difficult to find a program to do it for audio.

I don?t need more storage; I need to adapt my media for my storage. I am looking for a way to adapt my media for portability not for long term storage. I have a phone that offers 24GB to 40GB for storage, why should I waste that space with unneeded bits?

Its like downloading video at 1920x1080 or 480x800, your phone has a resolution of 480x800 so why would you store a HD video on it?

An audio book contains only one track of one voice. There is NO need for anything higher than 32bits per sec.

Now if you have anything helpful to add, please add it, but otherwise don?t waste either of our time.

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Good luck with your research.
Nov 9, 2010 8:15PM PST

I did find a whole host of articles in Google with the term Bitrate converter, eg this one;

I have little experience at this so at the risk of you thanking me for nothing, and "absolutely NO help whatsoever", I would say that the lower the bitrate, the poorer the quality. But then you already knew that.

I also found, in Google, articles on How to Compress MP3 Songs for a Mobile Phone, eg the one at;

Glad we could help.


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Re: mp3 to mp3
Nov 9, 2010 8:30PM PST

Yes, I see your problem.

The results of conversion are always best if your source is the best original you have. Piling up conversion upon conversion is suboptimal, as you noticed when you did. So your problem is that you don't have a backup of the original .wav files.

- I'd first try to find a program that can write mp3's at a lower bitrate then 128 kB. Maybe cdex (free) does, I didn't check. Probably audacity does. Maybe there are others.
- Then see what these programs accept as input.
- Then, if necessary, convert your 128 kB mp3's to one of those inputs.
- Then convert to mp3 again and check the result.

For example, did you try to use audacity to convert those mp3's back to the .wav-format (that you forgot to backup)? If that sounds OK, see what programs have the best result (for your earbuds and ears) converting it to a lower bit rate mp3.

It might need some experimenting, but it surely isn't hopeless.


PS. A standard bitrate mp3 is some 1 Mb a minute. That's 20.000 minutes or 333 hours or 13.8 days of continuous listening (that's 3 weeks of 16 hour days) for the 20 GB storage on your phone. Somehow it isn't clear to me why you should need 6 or even 12 weeks of continuous listening on your phone. Most people come home to refresh the contents of their phone more often than that. But, of course, that's up to you.

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Converting With MediaMonkey
Nov 10, 2010 7:14AM PST

MediaMonkey might be able to do what you want. It has an option to convert audio files to different bit rates. Also, it can convert files to different formats.

It has another option that you might find useful: You can have it automatically convert the files when it loads them on your player without changing them in your library. My player (a Sony NWZ-A81Cool only supports a minimum bitrate of 32kbps with MP3s. Some of the podcasts I subscribe to have a bitrate below that, so I have MediaMonkey automatically raise the bitrate of any MP3 with a bitrate of less than 32kbps to 32kbps when it loads them on my player.

I hope this helps.

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Thank you
Nov 11, 2010 6:38PM PST

Thank you MDFlax, Kees_B, and Solitare001 the three of you have been helpful.

I will try everything you have suggested, and write back with my results.

I have tried Audacity once before for the original rip but the outcome was unpleasant regardless of the bit rate.

I know this solution isn?t the best and I shouldn?t do it for music, but I figure since the original source material is hard to get a hold of and that it is just a single spoken voice; this might work.

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Let me explain...
Nov 11, 2010 7:18PM PST

To further explain; right now I have a 16 gig SD micro card in my phone, I have music ebooks, pdf, word, excel, and hundreds of roms already stored. I want to include a slew of other media too, like movies, tv shows, and a few audio books. As it stands right now the audio books take up the largest portion of that card. Seven books equal almost 7 gig.
I figured that I should spring for a 32 gig card (which I have), but even then 7 gig is still a large portion.

Now, I know I could repeatedly overwrite the files with other books, if I wanted to, but keep in mind that Flash memory isn't flawless, gates fail. The more you write Flash the more chance a gate has to be frozen, limiting the expanse of the storage.

I didn't forget to backup my audio books. I chose not to backup the original wav file. For many of us a high rate mp3 of music is just as good, even though I don?t agree. I have all my original music CDs. However when it comes to an audio book a wav file far exceeds overkill. My audio book collection as of right now is over 120 gig, and that is just at a rate of 128kbps, if I had backed that up as lossless wav, I would be looking at hundreds of blu-rays and the death of a blu-ray writer.

All of my audio books are now in circulation with my District Library, so I can still get a hold of them if worse comes to worst, but that could take months.

If I can EASILY negotiate this task, I will find myself with the same seven gigs of space filled with 28 large audio books instead of just seven or the same seven audio books but have them only take up 1.7 gigs. I don?t know about you guys, but I really like the prospect of carrying around with me as much entertainment and utility as I possibly can.

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Easy solution found!
Dec 20, 2010 4:45AM PST

I can't believe I didn't notice this before: I am running XP sp3 and with that OS when I right click on an audio file there is an option in that menu that allows you to "Convert audio format". This doesn't allow for less than 128k in mp3 but it does allow for 32k in wma.

So I converted all the audio books that I want to have on my phone down to 32k wma from 128k mp3, and it worked GREAT! It was definitely NOT a "Don't do it" situation.

Not only does the single layer audio track of an audio book sound great, but music files sound great too. I took some sample music from 320k mp3 and converted to 32k wma, and it was surprisingly fantastic. Sure you can tell the difference, but it most definitely did not sound awful... it sounded good, no wait, it sounded great!

I just can't believe that three "moderators" from the cnet forums couldn't point me in this direction from the very beginning.

Seriously guys (moderators), you offered not much of any help. You just made assumptions, failed to read and comprehend my original post, and failed to know the most common OS of the common end-user.

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Re: convert
Dec 20, 2010 5:07AM PST

Indeed, it's on my PC also. But I think it's limited to XP Media Center edition, and that's less common than Home or Professional.

Moreover, in your original post you stated "it must be a mp3-to-mp3-exchange". No mention at all that wma would be good also. That changes the problem. And it allows for a much better solution.

Thanks for the feedback!


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Jul 21, 2011 4:17AM PDT

I admire your calm response. Some people get too demanding and juvenile when requesting free advice.

Kudo's to you and the other moderators.

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