Tech: .mp3 file no smaller than .wav file

Subject: Tech: .mp3 file no smaller than .wav file
From: GUEST,Ed
Date: 16 Dec 08 - 11:19 AM

Hi,

I have a 21MB mono .wav file which I wish to email to someone. However when I try to convert it to mp3 format I get no reduction in file size (in fact it's a few KB bigger!). I can get the file down to about 15MB by reducing the bitrate to 96kbps but I wouldn't want to go any lower.

I've tried this using Audacity and Switch but get the same results. Any ideas?

Thanks,

Ed

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: Bernard
Date: 16 Dec 08 - 12:03 PM

Perhaps the sample rate of the original mono file is already quite low. How long should the audio run for? An average 4 minute stereo CD track sampled at 44.1k will usually be around 4Mb as an MP3 at 128K - approximately 'a meg a minute'.

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: wysiwyg
Date: 16 Dec 08 - 01:03 PM

One work-around would be to run the .wav thru Total Recorder, capturing the result as an MP3 of the desired quality (meg a minute) instead of converting it.

~S~

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: Jack Blandiver
Date: 16 Dec 08 - 02:41 PM

Whatever the size of your file, don't email it! Send it via YouSendIt - it's free, it's safe, it's efficient, it's quick & it won't crash!

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: GUEST,Ed
Date: 16 Dec 08 - 03:16 PM

Bernard,

I think you may have hit on the problem. The file in question is a recording of a commercial telephone call. I don't know what software was used to record it, but it will be some 'enterprise' type of thing, hence perhaps the low original sample rate.

The above is just guessing though, so if someone could explain why a low original sample r

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: GUEST,Ed
Date: 16 Dec 08 - 03:20 PM

Pressed wrong button:
The above is just guessing though, so if someone could explain why a low original sample rate would affect the mp3 compression rate, I'd appreciate it.

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: treewind
Date: 16 Dec 08 - 03:47 PM

MP3 is designed to compress high quality audio to a lower bit rate without losing much audio quality. Your low-rate .WAV already has a lot of information stripped out of it and a much smaller file size than a CD-quality WAV of the same length of time would have been.

In other words, to put it crudely, it's already been compressed so you can't compress it more.

For a phone voice recording, your WAV file could well be:
8kHz sampling (instead of 44kHz, more than 5 times reduction)
mono instead of stereo (2x reduction)
8 bits instead of 16 bits (2x reduction again)
That's 20 times smaller than a CD-quality WAV would have been, and those figures are standard for digital telephony.

With some unusual settings for your MP3 encoder (including a low bit rate) you might get it a little smaller, but not much. You're better off sending the file as it is. It must have have been a long phone call.

Anahata

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: Bernard
Date: 16 Dec 08 - 03:50 PM

Wot he just said!

;o)

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: GUEST
Date: 17 Dec 08 - 03:12 PM

Just resample it. Re-record it in something like CoolEdit Pro - or even Sound Forge, and save it as an Mp3. Save it as 44.1k or 22k and and - as Bernard above said - this should work out about 1 meg a minute.
Mike

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: GUEST
Date: 17 Dec 08 - 03:21 PM

...and probably no smaller than the original!

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: treewind
Date: 17 Dec 08 - 03:23 PM

Sorry, that was me, minus cookie

Anahata

Subject: RE: Tech: .mp3 file no smaller than .wav file
From: Gene
Date: 17 Dec 08 - 06:28 PM

WHY reduce the bit rate or quality any at all????

simply go to sendfile and upload the complete file.

Recipient gets an email saying the file is ready for download...

Gene

you can send up to 90Meg+ FREE [approximately 2 cds worth]

assuming you are NOT ON DIALUP...