Why original file size increase after editing mp3 files

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M&M
Posts: 4
Joined: Fri Nov 20, 2009 2:58 pm
Location: Joliette

Why original file size increase after editing mp3 files

Post by M&M »

I record an internet radio with WireTap Studio and every sample that I record it's about 28.3 MB before editing.

I use Amadeus Pro to edit the content of the file since I don't need all the material that it is recorded, I do some trimming, (fade in, fade out and normalize effects) nothing out of the ordinary.

But I did noticed that after pressing the save button, some files decrease in size which I belive is normal, but some others have a greater file size that originaly where. (from 28.3 MB to 41 MB)

Does anybody have an idea why this happens?

alansilv
Posts: 31
Joined: Thu Feb 07, 2008 6:16 pm
Location: Southern California, USA

Post by alansilv »

Just a guess, but it could be the difference between the original mp3 bitrate and the settings for saving as mp3 in your Amadeus Pro. When you open up an mp3 to edit the program actually gives you an uncompressed PCM (wav or aiff) file to work on. Then when you save as mp3 it compresses the edited file back to mp3. However, if your mp3 settings are different from the settings for the original file, the new one will be a different size. Say, for instance, your original was compressed at 128kbps bitrate, but your save-as settings for mp3 are 96kbps bitrate. Then the new file would be only about 2/3 the size of the original. Or vice versa: if the original was 128 and your save-as setting is 192 then the new file will be about 1/3 larger than the original. However, if you match the settings the original and save-as file should be about the same size.

M&M
Posts: 4
Joined: Fri Nov 20, 2009 2:58 pm
Location: Joliette

Post by M&M »

Thank you alansilv.

I guess you have the right anwser.

What I just don't understand is that all the files are recorded with the same settings (96kbps). So why Amadeus doesn't use the same settings to save the file instead of saving it with a much higher setting. (320kbps).

I use the save button direct on the tool pannel.

Once more, thank you for your reply.

Have a good day

alansilv
Posts: 31
Joined: Thu Feb 07, 2008 6:16 pm
Location: Southern California, USA

Post by alansilv »

I'm pretty sure that if you change the bitrate when you save your next file (use the "settings" button next to the file type in the save dialog box) it will retain that setting until you change it again. So if you want your files at 96kbps, change it to that and the next time you go to save a file it should already be at 96. Hope that helps.

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