October 11, 2009
Britain's Central Planning Death Panels
October 11, 2009
Free Market M.D.
October 11, 2009
Economies of Scale in Compliance
October 11, 2009
Balan's Challenge
October 10, 2009
The Pleasure of Telling Others What to Do
October 10, 2009
Gonick the Great - and How He Could Have Been Greater
October 9, 2009
More Scott Sumner
October 9, 2009
Not From The Onion
October 9, 2009
Thoughts on a Second Stimulus
There are lot's, but I use iTunes. If you encode in mono at 16 kbs, which I do for some talk radio programs, an hour's worth is around 7 MB.
You might try lame, if the licensing is not an issue. http://lame.sourceforge.net/using.html
Something like: lame -b 32 infile.wav outfile.mp3 will result in a quite small mp3. See
http://lame.sourceforge.net/USAGE for more info about various options. Size is of course traded for quality.
Hey. I got all eight right.
As usual, I find open-source based software hard to figure out. The best I could do with one LAME-based tool I downloaded was slightly worse than what I could do with something called Coffee Cup rip-and-burn. That is, the file was slightly larger with the open source stuff. But I have no idea how to optimize the open source stuff.
I think that if one could set the bitrate rate from 32 k down to 8 k it might help. But I don't know how to do that, and it's just a guess, anyway.
You should reduce the sampling rate to 12 kHz in order to get small file sizes. In doing so, you remove all frequencies above 6 kHz, which will not adversely affect the intelligibility of the recording; on the other hand, it will make high-frequency artifacts from the Olympus files less obvious. Using LAME, the following is pretty good for spoken recordings:
lame --resample 12 -b 24 -m m
That'll be a mono file at 24 kbps.
There are several good solutions for low bit-rate audio. A recent test of them was summarized at the following site: http://www.rjamorim.com/test/32kbps/results.html
Most of them are problematic at very low rates, not least because they would require your users to download new software to listen. If you assume they have iTunes, the AAC seems like a good bet.
The program dbpoweramp can make it easier to convert audio formats than some others. It can be used with the aforementioned LAME as well as many other codecs.
"Most of them are problematic at very low rates, not least because they would require your users to download new software to listen."
That's what's true of the dss format in which I make the recordings. You have to download the software, and on top of that the browser tries to read the format as an HTML page, so you have to save the file to disk and then listen to it. That's what I mean by being a user-hostile format.
I tried re-encoding one of your MP3 files as 8 kbps mono AAC using iTunes and I got a pretty decent quality at 1/4th the size. You might want to try that.