ref: 74fcae28e6618ef19ba1b219b05e958475423a46
parent: 7ef50e0130b8cdbf43f050f0de23e855e4a187f3
author: robs <robs>
date: Tue Jan 23 18:41:21 EST 2007
Further null & synth clarification.
--- a/sox.1
+++ b/sox.1
@@ -45,6 +45,14 @@
If invoked as `play', the output file is the default sound device. If
invoked as `rec', the input device is the default sound device.
.SP
+Usually SoX will complete its processing and exit automatically, however
+if desired, SoX's processing can be terminated early by pressing the
+keyboard interrupt key (usually Ctrl-C). This is a natural requirement
+in some circumstances, e.g. when using SoX to make a recording. Note
+that when using SoX to play multiple files, Ctrl-C behaves slightly
+differently: pressing it once causes SoX to skip to the next file;
+pressing it twice in quick succession causes SoX to exit.
+.SP
The overall SoX processing chain can be summarised as follows:
.SP
.ce
@@ -297,8 +305,7 @@
.SP
rec \-c 2 take1.aiff
.SP
-starts a stereo recording that will finish when the interrupt key (often
-Ctrl-C) is pressed.
+begins a stereo recording that will end when Ctrl-C is pressed.
.SP
Other examples can found throughout this manual and in the
separate
@@ -305,8 +312,8 @@
.BR soxexam (7)
manual.
.SH FILENAMES
-The following may be used in certain circumstances in place of a normal
-filename on the command line:
+The following `special' filenames may be used in certain circumstances
+in place of a normal filename on the command line:
.TP
\fB\-\fR
SoX can be used in pipeline operations by using the special
@@ -321,8 +328,10 @@
below) must also be given.
.TP
\fB\-n\fR
-This can be used in place of an input or output filename
-to specify that a `null' file is to be used.
+This can be used in place of an input or output filename to specify that
+a `null file' is to be used. Note that here, `null file' refers to a
+SoX-specific mechanism and is not related to any operating-system
+mechanism with a similar name.
.SP
Using a null file to input audio is equivalent to
using a normal audio file that contains an infinite amount
@@ -335,8 +344,9 @@
audio instead of affecting it (such as \fBnoiseprof\fR or \fBstat\fR).
.SP
The number of channels and the sampling rate associated with a null file
-are by default 2 and 44\*d1\ kHz respectively, but these can be overridden
-if necessary by using appropriate command-line format options.
+are by default 2 and 44\*d1\ kHz respectively, but, as with a normal
+file, these can be overridden if desired using command-line format
+options (see below).
.SP
One other use of \fB\-n\fR is to use it in conjunction with
.B \-V
@@ -1904,20 +1914,20 @@
Audio for each channel in a multi-channel audio file can be synthesised
independently.
.SP
-Though this effect is used to generate audio, an input file must
-still be given. This can be used to set the synthesised audio
-length, the number of channels, and the sampling rate, however since the
-input file's audio is not needed, the null
-file `\fB\-n\fR' is usually given instead (and the length specified
-as a parameter to \fBsynth\fR or by another given effect that can has an
-associated length).
+Though this effect is used to generate audio, an input file must still
+be given, the characteristics of which will be used to set the
+synthesised audio length, the number of channels, and the sampling rate;
+however, since the input file's audio is not normally needed, a `null
+file' (with the special name \fB-n\fR) is often given instead (and the
+length specified as a parameter to \fBsynth\fR or by another given
+effect that can has an associated length).
.SP
For example, the following produces a 3 second, 44\*d1\ kHz,
-stereo audio file containing a sine-wave swept from 300 to 3300\ Hz.
+stereo audio file containing a sine-wave swept from 300 to 3300\ Hz:
.SP
sox \-n output.au synth 3 sine 300\-3300
.SP
-This produces an 8\ kHz mono version:
+and this produces an 8\ kHz mono version:
.SP
sox \-r 8000 \-c 1 \-n output.au synth 3 sine 300\-3300
.SP