Re: Recording specific channels

On May 13 16:46:50, [email protected] wrote:
> On May 13 09:26:10, [email protected] wrote:
> > On May 12 22:56:45, [email protected] wrote:
> > > If someone needs files from 1:35 to 3:15 we just give them 1 to 4.
> > > They combine them (with no seam at 2pm) [...] We routinely combine files
> > > into larger segments and we need them to be seamless.
> > 
> > Ah, right, that's what you mean by "sample perfect". Let's try:
> > 
> > $ sox -n sine.wav synth 10
> > $ sox sine.wav part%n.wav trim 0 5 : newfile : trim 0 5
> > $ soxi sine.wav part*.wav
> > 
> > On my machine, that's 480000 split into 240000 + 240000 exactly
> > when I said 5s out of 10s.
> 
> On the contrary, this is not sample perfect:
> a line in my crontab, starting a recording of one minute every minute.
> 
> * * * * * /Users/hans/bin/rec -q /tmp/file-`date +\%s`.wav trim 0 00:01:00
> 
> This does indeed record each minute of audio into
> an appropriately named file, but the transition is not seamless
> (as verified by playing a song longer than one minute).

On the other hand, that's not SoX's fault:
it get started when OSX's scheduler starts it;
then it records precisely one minute of audio.

> But if you change this to record your "predefined blocks"
> of a couple of hours, then perhaps overlaping a few samples
> will not matter if the seams are at silent times.

Much like you do with restarting Logic after 12 hours:
restart SoX every 24 hours, spawning a new file.