hey, i wasn't sure where to post this question... but im looking for an audio recorder to record class lectures w/ my laptop (it has a built-in mic). additionally, hdd space on my laptop is limited, and 45 min wav files would get alittle rediculous, so i was wondering if it was possible to record directly to something smaller, speex ideally. that is not essential, but would be nice. what do you guys know of?

Good question.

I'm searching something like you say, but going a bit further, lossless but quick enough for realtime recording.

Speex need some time to analyse and encode, seems not possible recording realtime. Or can I hope that a almighty wizard suddenly appear and make an assembly codec/Directshow SPEEX filter quick enough for realtime?

If you don't mind command line applications you can use an old tool I wrote, piperec. It records audio from your default recording device and outputs it as WAV into standard output. To record with speex you can use a command line like 'piperec 16000 16 2 | speexenc - - > C:\test.spx', that records 16kHz stereo file and writes output as C:\test.spx.

that sounds good case, but i have very little experience w/ command line apps and am unsure of how to get this to work. i extracted your files into c:\program files\piperec\, and then copied piperec.exe into my system32 folder. then i used the command line "piperec 16000 16 2 | speexenc - - > C:\test.spx" in the command propmt window, and i got "'speexenc' is not recognized as an internal or external command, operable program or batch file." im not sure what im doing wrong. sorry for my ignorance...

The possibilities: either your laptop is something slower than a Pentium 100 Mhz, or you're talking through your ass here. On my laptop (a 1.6 GHz Pentium-M), I'm able to encode in real-time with only 1% CPU! If want you want is lossless though, FLAC will do the trick and it's (AFAIK) even faster than Speex.

You should also have the speexenc.exe encoder executable somewhere...

There's a program called LiveInCode. It's got a GUI. Maybe it would be of interest...?

wow, i feel really stupid... thanks. thats just embarassing

ahhh, thats nice. thanks. no offense case, but that is, for me at least, alot easier. i think LiveInCode is what i will be using. im going to have to experiment w/ the different speex settings and see what works best though. any specific recommendations on what speex settings would be good for recording lectures in large rooms w/ minimal file size? quality of sound is not important, just intelligibility.

Foobar2000 can do that too, but I do not know any speex direct encoder for foobar
Foobar2000 can encode to Nero He-aac directly


dBpoweramp Music Converter is another good program

download it
and use its "dMC Auxilary Input"

You will see a RECORD button
choose "Record (with Options)", then you can choose whatever format you want


http://www.dbpoweramp.com/dmc.htm

and the speex plugin for dMC here:

http://www.dbpoweramp.com/codec-central-speex.htm

You just have to experiment with the settings I guess, but one recommendation I will give are to overwrite the speexenc that comes bundled with a newer build. Personally I use Speex 1.1.7 Unstable Release for Win32 from RareWares. I think the sound has improved with newer versions. (BTW. Don't forget to download the libmmd.dll too, if you're gonna use the ICL 8.1 compile.)


EDIT: Typo.

ok, ive got the newer version of the speex encoder, but what do i do w/ the libmmd.dll? should it go in system32? or in the liveincode directory w/ the speex encoder exe?

edit: oh, and ive never understood the bits/sample setting in audio. i know that may sound very basic, but i have just never understood. i know that cd's are @ 16 bits. liveincode gives the option of encoding in 8 or 16 bits/sample. would the difference be in sound quality and file size? if so, would 8 bit be half the size of 16 bit?

Easiest for you (and you might use other RareWares compiles), not having to think about it again, is to put it in some common %PATH%. On w2k/XP C:\Windows\System32 will be a good solution, on 9x/ME C:\Windows\System.


For simple voicerecording with Speex I find that 16000 Hz 16 bit mono gives reasonably good payback size/quality wise... I think that's a good starting point. For me 8 bit sounds too harsh, especially the backgroundnoise gets some annoying characteristics... 16000 Hz samplerate gives you cutoff at 8000 Hz, which I guess are acceptable for speech. I wouldn't think there's any need for stereo when recording like you intend too.

But try it out and increase or decrease quality after your own jugdement.

EDIT: Yes, eh size...
For a wav file converting from 16 bits to 8 bits will half the size. But I now took a wav file from an ordinary Audiobook, converted it to one 16kHz/16bit/mono wav file and to one 16kHz/8bit/mono wav file. The first file is 1.50 MB, the other 0.75 MB. I then encode as VBR Speex (and I guess you will use VBR, why not?). The first file are now 126 KB, the second 121 KB, the difference in quality are however striking....
(But so is it for the wav files too, 8 bit sound very harsh.)

MORE EDIT: Tested some more recording from line in. Doesn't seem much to save in filesize choosing 8 bit over 16 bit. Great loss in quality. Optimal settings for me with LiveInCode seems to be (considering purpose are to record speech using as little diskspace as possible, still maintaining acceptable quality):
Codec: Speex. Sample Rate: 16000. Bits per sample: 16. Channels: 1. VBR enabled. Quality: 8.