Subject: Re: [linux-audio-user] why is my mp3 file bigger than my wav file?
From: Kai Vehmanen (kai.vehmanen_AT_wakkanet.fi)
Date: Sat Feb 02 2002 - 16:02:57 EET
On 1 Feb 2002, Laura Conrad wrote:
> ecasound -i /dev/dsp -o lingham.wav
> ecasound -i lingham.wav -o lingham.mp3
> -rw-rw-r-- 1 lconrad lconrad 2322432 Feb 1 17:11 lingham.mp3
> -rw-rw-r-- 1 lconrad lconrad 1163619 Feb 1 17:06 lingham.wav
My guess is that the lingham.wav is in 8bit, mono, 8kHz format. In this
case the above figures make sense. A 2.3MB mp3 file encoded at 128kbit/s
contains around 2.5 minutes of audio. Ok, let's calculate how much a
2.5min, 8bit/1ch/8000Hz wav file would take:
x min * secs/min * samples/second * channels * bytes/samples = y bytes
2.5*60*8000*1*1 = 1200000
This is pretty close to your 11636619. If you had recorded with
cd-quality, the wav would have been...
2.5*60*44100*1*2 = 13230000 (~13.2MB or 12.67 MiB)
> The point of making the mp3 file was to get the compression -- what
> did I do wrong?
Mp3 and similar compression mechanisms are good for preserving quality of
cd-quality (or similar) audio content, while reducing file sizes. In your
case, the source file already was of low quality.
-- http://www.eca.cx Audio software for Linux!
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