Martin McCormick wrote: > This appears to be right on target except I am going to need >to play a bit with the input file and probably name it something else >than a .wav file. > > I connected a stereo tape recorder to the two inputs of the >sound card and used the following command to capture 2 tracks of audio >containing separate program material recorded at 1-and-7/8 IPS. >That's the reason for the low sample rate: > >arecord -d 86400 -t wav -r 8000 -F S8 -c 2 2channelarchive.wav > > You must mean: arecord -d 86400 -t wav -r 8000 -f S8 -c 2 2channelarchive.wav -f is format, -F is period time. Why create a 2-channel file only to split them? Why not: arecord -d 86400 -t wav -r 8000 -f S8 -c 2 -I ch1.wav ch2.wav I see another problem. It appears that arecord is not putting a proper WAV file header on the output file(s). That might be why sox is getting a little confused. When you run acrecord and it says "Recording raw data..." that's what the output file is, despite the "-t wav" argument. If arecord says "Recording WAVE...." then your output file has a proper header. Further, if you run arecord with the argument "-F S8" you really get unsigned 8 bit output. arecord won't accept "-f S8" while "-F S8" is silently ignored and you get unsigned 8 bit output anyway. So the command I have above doesn't actually work, arecord says "arecord: begin_wave:1612: Wave doesn't support S8 format...", but this works: arecord -d 86400 -t wav -r 8000 -f U8 -c 2 -I ch1.wav ch2.wav except that ch1.wav and ch2.wav are raw, headerless files, without WAV headers. sox doesn't like to see raw, headerless files with names ending in .wav, but once I rename ch1.wav and ch2.wav to ch1.raw, ch2.raw I can use sox to put a proper WAV header on the files with: sox -r 8000 -u -b ch1.raw ch1.wav Alternately, arecord does create a proper 2-channel WAV file, so you could record with this: arecord -d 86400 -t wav -r 8000 -f U8 -c 2 twochan.wav And then split it with: sox twochan.wav -c 1 leftchan.wav avg -l And your resulting leftchan.wav will be 8 bit, unsigned, 8000 sample/sec, with a proper WAV header. wes
