frequency encoding on mp3s
 

I am having mplayer dump audio streams into a wav file. These files are 1 hour talks with no music. These are updates to the same subject and in the past these files were encoded to mp3s that have a frequency of 16 kHz and 24 bits. Using lame I type:

lame -s 16 -b 24 file.wav file.mp3

This produces a file with a frequency of only 8 kHz and 24 bits. The audio quality is poor and there is a lot of popping.

What am I doing wrong? Is there a GUI for lame that lets you adjust the frequency? Audacity seems to only let you adjust the bit rate.

Audacity frequency adjustment is right on the front page.

Left bottom corner. I see. I changed it to 16000 and set the preferences to encode at 24 bits and then exported as an mp3. When I played it in xmms I heard a lot of popping sounds and saw that it recorded at 8 kHz and 24 bits. Maybe I need to strip the headers off this wav file so it won't equate 8 kHz with 24 bits? How?

If you are making a PCM recording of speech, it's dramatic overkill. Why not record natively in MP3? When converting to other formats, the sampling rate should be 44.1KHZ to avoid problems.

8KHz bandwidth for speech is probably not enough unless you can tolerate a lot of pumping and other artifacts. You should be fine with 16KHz and probably not go higher unless you like wasting media.

Bandwidth and bit rate are related but not identical concepts. If you are trying to save the file at a certain bit rate, 20kbps should be fine for speech.

I'm actually downloading mp3 streams like this:

mms://media1.ccphilly.org/Teaching/Audio/B06_Joshua/SPM20164.mp3

I know the actual mp3 files exist, I just cannot find the download location on the web. What I do is dump this stream to a wav file with mplayer. This produces a huge file which I convert back to an mp3 with lame and tag with Easy Tag (the lame -t switches don't seem to work). Then I delete the wav files from my harddrive and put the mp3s on my mp3 server for streaming or download.

Long process, and if I could find the download location of the mp3 I'd be grateful-any ideas?

Bit offtopic:
They are using fasttrack on their server, so you may find these media on p2p. Look here: http://www.slyck.com/ft.php

I don't understand why you don't just save the mp3. Your link shows that you know the location. Why are you using mplayer if you know the url? Just type the link in a browser and "Save As"

I think save as does not work for these type of files. MMSH (mms encapsulated in http) protocol is being used, which is a product of Microsoft.