add "loopback" mode in which input is connected to the output.

This is useful to mix, demultiplex, resample or reencode audio
files off-line.
tweak + ok jakemsr

4 files changed, 113 insertions, 16 deletions

diff --git a/usr.bin/aucat/aucat.1 b/usr.bin/aucat/aucat.1
index e73e823df2e..03a58e7f74c 100644
--- a/usr.bin/aucat/aucat.1
+++ b/usr.bin/aucat/aucat.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: aucat.1,v 1.41 2008/12/05 07:03:52 jmc Exp $
+.\"	$OpenBSD: aucat.1,v 1.42 2009/01/10 20:02:28 ratchov Exp $
 .\"
 .\" Copyright (c) 2006 Alexandre Ratchov <alex@caoua.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: December 5 2008 $
+.Dd $Mdocdate: January 10 2009 $
 .Dt AUCAT 1
 .Os
 .Sh NAME
@@ -23,7 +23,7 @@
 .Sh SYNOPSIS
 .Nm aucat
 .Bk -words
-.Op Fl lu
+.Op Fl lnu
 .Op Fl b Ar nsamples
 .Op Fl C Ar min : Ns Ar max
 .Op Fl c Ar min : Ns Ar max
@@ -102,6 +102,12 @@ and
 for play-only, record-only, and full-duplex, respectively.
 The default is
 .Ar duplex .
+.It Fl n
+Loopback mode.
+Instead of using an audio device, send input streams
+to the output, processing them on the fly.
+This mode is useful to mix, demultiplex, resample or reencode
+audio files off-line.
 .It Fl o Ar file
 Add this file to the list of files in which to store recorded samples.
 If the option argument is
@@ -343,6 +349,11 @@ both:
 $ aucat -r 96000 -C 2:3 -o file1.raw -C 6:7 -o file2.raw
 .Ed
 .Pp
+The following will split a stereo file in two mono files:
+.Bd -literal -offset indent
+$ aucat -n -i stereo.wav -C 0:0 -o left.wav -C 1:1 -o right.wav
+.Ed
+.Pp
 The following will start
 .Nm
 in server mode using default parameters, but will create an
diff --git a/usr.bin/aucat/aucat.c b/usr.bin/aucat/aucat.c
index 4cabe127593..298c63ccaa7 100644
--- a/usr.bin/aucat/aucat.c
+++ b/usr.bin/aucat/aucat.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: aucat.c,v 1.50 2008/12/29 17:59:08 ratchov Exp $	*/
+/*	$OpenBSD: aucat.c,v 1.51 2009/01/10 20:02:28 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -111,7 +111,7 @@ usage(void)
 	extern char *__progname;
 
 	fprintf(stderr,
-	    "usage: %s [-lu] [-b nsamples] [-C min:max] [-c min:max] [-e enc] "
+	    "usage: %s [-lnu] [-b nsamples] [-C min:max] [-c min:max] [-e enc] "
 	    "[-f device]\n"
 	    "\t[-h fmt] [-i file] [-m mode] [-o file] [-r rate] [-s socket]\n"
 	    "\t[-v volume] [-x policy]\n",
@@ -312,7 +312,7 @@ newoutput(struct farg *fa)
 int
 main(int argc, char **argv)
 {
-	int c, u_flag, l_flag, hdr, xrun, suspend = 0;
+	int c, u_flag, l_flag, n_flag, hdr, xrun, suspend = 0;
 	struct farg *fa;
 	struct farglist  ifiles, ofiles, sfiles;
 	struct aparams ipar, opar, dipar, dopar;
@@ -336,6 +336,7 @@ main(int argc, char **argv)
 	aparams_init(&opar, 0, 1, 44100);
 	u_flag = 0;
 	l_flag = 0;
+	n_flag = 0;
 	devpath = NULL;
 	SLIST_INIT(&ifiles);
 	SLIST_INIT(&ofiles);
@@ -346,8 +347,11 @@ main(int argc, char **argv)
 	bufsz = 44100 * 4 / 15; /* XXX: use milliseconds, not frames */
 	mode = 0;
 
-	while ((c = getopt(argc, argv, "b:c:C:e:r:h:x:v:i:o:f:m:lus:")) != -1) {
+	while ((c = getopt(argc, argv, "nb:c:C:e:r:h:x:v:i:o:f:m:lus:")) != -1) {
 		switch (c) {
+		case 'n':
+			n_flag = 1;
+			break;
 		case 'm':
 			mode = opt_mode();
 			break;
@@ -446,6 +450,12 @@ main(int argc, char **argv)
 		if (l_flag || !SLIST_EMPTY(&ofiles))
 			mode |= MODE_REC;
 	}
+	if (n_flag) {
+		if (devpath != NULL || l_flag)
+			errx(1, "can't use -n with -f or -l");
+		if (SLIST_EMPTY(&ifiles) || SLIST_EMPTY(&ofiles))
+			errx(1, "both -i and -o are required with -n");
+	}
 
 	/*
 	 * if there are no sockets paths provided use the default
@@ -490,15 +500,20 @@ main(int argc, char **argv)
 		DPRINTF("sigaction(usr2) failed1n");
 #endif
 	filelist_init();
+
 	/*
 	 * Open the device. Give half of the buffer to the device,
 	 * the other half is for the socket/files
 	 */
-	dev_init(devpath, 
-	    (mode & MODE_REC) ? &dipar : NULL,
-	    (mode & MODE_PLAY) ? &dopar : NULL,
-	    bufsz);
-
+	if (n_flag) {
+		dev_loopinit(&dipar, &dopar, bufsz);
+	} else {
+		dev_init(devpath, 
+		    (mode & MODE_REC) ? &dipar : NULL,
+		    (mode & MODE_PLAY) ? &dopar : NULL,
+		    bufsz);
+	}
+	
 	/*
 	 * Create buffers for all input and output pipes.
 	 */
@@ -530,7 +545,7 @@ main(int argc, char **argv)
 			break;
 		}
 		if ((!dev_rec || dev_rec->u.io.file == NULL) &&
-		    (!dev_play || dev_play->u.io.file == NULL)) {
+		    (!dev_play || dev_play->u.io.file == NULL) && !n_flag) {
 			fprintf(stderr, "device desappeared, terminating\n");
 			break;
 		}
@@ -563,7 +578,10 @@ main(int argc, char **argv)
 		suspend = 0;
 		dev_start();
 	}
-	dev_done();
+	if (n_flag) {
+		dev_loopdone();
+	} else
+		dev_done();
 	filelist_done();
 
        	sigfillset(&sa.sa_mask);
diff --git a/usr.bin/aucat/dev.c b/usr.bin/aucat/dev.c
index e97dcf57e08..a72513abe57 100644
--- a/usr.bin/aucat/dev.c
+++ b/usr.bin/aucat/dev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dev.c,v 1.23 2009/01/06 19:27:22 ratchov Exp $	*/
+/*	$OpenBSD: dev.c,v 1.24 2009/01/10 20:02:28 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -29,6 +29,72 @@ unsigned dev_bufsz, dev_round, dev_rate;
 struct aparams dev_ipar, dev_opar;
 struct aproc *dev_mix, *dev_sub, *dev_rec, *dev_play;
 
+/*
+ * same as dev_init(), but create a fake device that records what is
+ * played
+ */
+void
+dev_loopinit(struct aparams *dipar, struct aparams *dopar, unsigned bufsz)
+{
+	struct abuf *buf;
+	struct aparams par;
+	unsigned cmin, cmax, rate;
+
+	cmin = (dipar->cmin < dopar->cmin) ? dipar->cmin : dopar->cmin;
+	cmax = (dipar->cmax > dopar->cmax) ? dipar->cmax : dopar->cmax;
+	rate = (dipar->rate > dopar->rate) ? dipar->rate : dopar->rate;
+	aparams_init(&par, cmin, cmax, rate);
+	dev_ipar = par;
+	dev_opar = par;
+	dev_round = (bufsz + 1) / 2;
+	dev_bufsz = dev_round * 2;
+	dev_rate  = rate;       
+	dev_rec = NULL;
+	dev_play = NULL;
+	
+	buf = abuf_new(dev_bufsz, &par);
+	dev_mix = mix_new("mix", dev_bufsz);
+	dev_mix->refs++;
+	dev_sub = sub_new("sub", dev_bufsz);
+	dev_sub->refs++;
+	aproc_setout(dev_mix, buf);
+	aproc_setin(dev_sub, buf);
+
+	dev_mix->u.mix.flags |= MIX_AUTOQUIT;
+	dev_sub->u.sub.flags |= SUB_AUTOQUIT;
+
+	*dipar = dev_ipar;
+	*dopar = dev_opar;
+}
+
+/*
+ * same as dev_done(), but destroy a loopback device
+ */
+void
+dev_loopdone(void)
+{
+	struct file *f;
+
+	DPRINTF("dev_loopdone:\n");
+
+	dev_sub->refs--;
+	dev_sub = NULL;
+	dev_mix->refs--;
+	dev_mix = NULL;
+	/*
+	 * generate EOF on all inputs
+	 */
+ restart:
+	LIST_FOREACH(f, &file_list, entry) {
+		if (f->rproc != NULL) {
+			file_eof(f);
+			goto restart;
+		}
+	}
+	while (file_poll())
+		; /* nothing */
+}
+
 unsigned
 dev_roundof(unsigned newrate)
 {
diff --git a/usr.bin/aucat/dev.h b/usr.bin/aucat/dev.h
index 5933f5c7f46..3889f6c58a3 100644
--- a/usr.bin/aucat/dev.h
+++ b/usr.bin/aucat/dev.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dev.h,v 1.8 2008/12/07 17:10:41 ratchov Exp $	*/
+/*	$OpenBSD: dev.h,v 1.9 2009/01/10 20:02:28 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -28,6 +28,8 @@ extern struct aparams dev_ipar, dev_opar;
 extern struct aproc *dev_mix, *dev_sub, *dev_rec, *dev_play;
 
 unsigned dev_roundof(unsigned);
+void dev_loopinit(struct aparams *, struct aparams *, unsigned);
+void dev_loopdone(void);
 void dev_init(char *, struct aparams *, struct aparams *, unsigned);
 void dev_start(void);
 void dev_stop(void);