alsaloop: added option prateshift for PLAYSHIFT ctl elem used in PLAYSHIFT

If snd-aloop device is on playback side, the required sync mode is
PLAYSHIFT. That means Loopback ctl elem "PCM Rate Shift 100000" of the
corresponding capture side of the Loopback pipe must be controlled (by
a reciprocal).

ASCII name of the playback rate shift ctl elem is specified with newly
added option -x/--prateshift, e.g.:
  -P hw:Loopback,0 -S playshift \
  -x iface=PCM,name='PCM Rate Shift 100000',device=1

Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/alsaloop/alsaloop.1 b/alsaloop/alsaloop.1
index 6bacfd557789d7a3cadd649f4e52dbcbc8d092c2..006494ddfae1419b71a9f0ec14704796f120555a 100644 (file)
--- a/alsaloop/alsaloop.1
+++ b/alsaloop/alsaloop.1
@@ -57,6 +57,11 @@ Use given CTL device for playback.
 
 Use given CTL device for capture.
 
+.TP
+\fI\-x <ctl_ascii_name>\fP | \fI\-\-prateshift=<ctl_ascii_name>\fP
+
+Specify ctl ascii name for playshift sync mode (see the Examples section).
+
 .TP
 \fI\-l <latency>\fP | \fI\-\-latency=<frames>\fP
 
@@ -195,10 +200,12 @@ Verbose xrun profiling.
 Set process wake timeout.
 
 .SH EXAMPLES
-
-.TP
+.nf
 \fBalsaloop \-C hw:0,0 \-P hw:1,0 \-t 50000\fR
 
+\fBalsaloop \-C hw:soundcard,0 \-P hw:Loopback,0 \-t 50000 \-S playshift \\
+\-x iface=PCM,name='PCM Rate Shift 100000',device=1\fR
+.ne
 .SH BUGS
 None known.
 .SH AUTHOR

diff --git a/alsaloop/alsaloop.c b/alsaloop/alsaloop.c
index 06ffadfb19117570009c41c813cab1244920937e..4192712ed52da320347d5f68fcbf0bac0e88bfac 100644 (file)
--- a/alsaloop/alsaloop.c
+++ b/alsaloop/alsaloop.c
@@ -175,6 +175,7 @@ void help(void)
 "-C,--cdevice   capture device\n"
 "-X,--pctl      playback ctl device\n"
 "-Y,--cctl      capture ctl device\n"
+"-x,--prateshift playback 'PCM Rate Shift 100000' ascii ctl name\n"
 "-l,--latency   requested latency in frames\n"
 "-t,--tlatency  requested latency in usec (1/1000000sec)\n"
 "-f,--format    sample format\n"
@@ -362,6 +363,7 @@ static int parse_config(int argc, char *argv[], snd_output_t *output,
                {"cdevice", 1, NULL, 'C'},
                {"pctl", 1, NULL, 'X'},
                {"cctl", 1, NULL, 'Y'},
+               {"prateshift", 1, NULL, 'x'},
                {"latency", 1, NULL, 'l'},
                {"tlatency", 1, NULL, 't'},
                {"format", 1, NULL, 'f'},
@@ -391,6 +393,7 @@ static int parse_config(int argc, char *argv[], snd_output_t *output,
        char *arg_cdevice = NULL;
        char *arg_pctl = NULL;
        char *arg_cctl = NULL;
+       char *arg_prateshift = NULL;
        unsigned int arg_latency_req = 0;
        unsigned int arg_latency_reqtime = 10000;
        snd_pcm_format_t arg_format = SND_PCM_FORMAT_S16_LE;
@@ -420,7 +423,7 @@ static int parse_config(int argc, char *argv[], snd_output_t *output,
        while (1) {
                int c;
                if ((c = getopt_long(argc, argv,
-                               "hdg:P:C:X:Y:l:t:F:f:c:r:s:benvA:S:a:m:T:O:w:UW:z",
+                               "hdg:P:C:X:Y:x:l:t:F:f:c:r:s:benvA:S:a:m:T:O:w:UW:z",
                                long_option, NULL)) < 0)
                        break;
                switch (c) {
@@ -446,6 +449,9 @@ static int parse_config(int argc, char *argv[], snd_output_t *output,
                case 'Y':
                        arg_cctl = strdup(optarg);
                        break;
+               case 'x':
+                       arg_prateshift = strdup(optarg);
+                       break;
                case 'l':
                        err = atoi(optarg);
                        arg_latency_req = err >= 4 ? err : 4;
@@ -627,6 +633,9 @@ static int parse_config(int argc, char *argv[], snd_output_t *output,
                        logit(LOG_CRIT, "Unable to add ossmixer controls.\n");
                        exit(EXIT_FAILURE);
                }
+               if (arg_prateshift)
+                       play->prateshift_name = arg_prateshift;
+
 #ifdef USE_SAMPLERATE
                loop->src_enable = arg_samplerate > 0;
                if (loop->src_enable)

diff --git a/alsaloop/alsaloop.h b/alsaloop/alsaloop.h
index 1dbcefe68b966af5a21f9090c0ea150518bba8b2..7a98ef37baf4bf7b4bc8da27f4cce810892dd706 100644 (file)
--- a/alsaloop/alsaloop.h
+++ b/alsaloop/alsaloop.h
@@ -127,6 +127,7 @@ struct loopback_handle {
        snd_ctl_elem_value_t *ctl_format;
        snd_ctl_elem_value_t *ctl_rate;
        snd_ctl_elem_value_t *ctl_channels;
+       char *prateshift_name; /* ascii name for the playback rate shift ctl elem */
 };
 
 struct loopback {

diff --git a/alsaloop/pcmjob.c b/alsaloop/pcmjob.c
index 845ab82285dcf3b89229e9498eabb65674edd740..f87283dcb0690fe37bb0a4568b10948438b778a7 100644 (file)
--- a/alsaloop/pcmjob.c
+++ b/alsaloop/pcmjob.c
@@ -1101,7 +1101,8 @@ void update_pitch(struct loopback *loop)
 #endif
        }
        else if (loop->sync == SYNC_TYPE_PLAYRATESHIFT) {
-               set_rate_shift(loop->play, pitch);
+               // pitch is capture-based, playback side requires reciprocal
+               set_rate_shift(loop->play, 1 / pitch);
 #ifdef USE_SAMPLERATE
                if (loop->use_samplerate) {
                        loop->src_data.src_ratio = 
@@ -1172,32 +1173,57 @@ static int get_channels(struct loopback_handle *lhandle)
        return snd_ctl_elem_value_get_integer(lhandle->ctl_channels, 0);
 }
 
-static void openctl_elem(struct loopback_handle *lhandle,
-                        int device, int subdevice,
-                        const char *name,
-                        snd_ctl_elem_value_t **elem)
+static int openctl_elem_id(struct loopback_handle *lhandle, snd_ctl_elem_id_t *id,
+               snd_ctl_elem_value_t **elem)
 {
        int err;
 
        if (snd_ctl_elem_value_malloc(elem) < 0) {
                *elem = NULL;
+               return -ENOMEM;
+       }
+       snd_ctl_elem_value_set_id(*elem, id);
+       snd_ctl_elem_value_set_interface(*elem, SND_CTL_ELEM_IFACE_PCM);
+       err = snd_ctl_elem_read(lhandle->ctl, *elem);
+       if (err < 0) {
+               snd_ctl_elem_value_free(*elem);
+               *elem = NULL;
+               return err;
        } else {
-               snd_ctl_elem_value_set_interface(*elem,
-                                                SND_CTL_ELEM_IFACE_PCM);
-               snd_ctl_elem_value_set_device(*elem, device);
-               snd_ctl_elem_value_set_subdevice(*elem, subdevice);
-               snd_ctl_elem_value_set_name(*elem, name);
-               err = snd_ctl_elem_read(lhandle->ctl, *elem);
-               if (err < 0) {
-                       snd_ctl_elem_value_free(*elem);
-                       *elem = NULL;
-               } else {
-                       if (verbose)
-                               snd_output_printf(lhandle->loopback->output,
-                                               "Opened PCM element %s of %s, device %d, subdevice %d\n",
-                                               name, snd_ctl_name(lhandle->ctl), device, subdevice);
-               }
+               snd_output_printf(lhandle->loopback->output,
+                               "Opened PCM element %s of %s, device %d, subdevice %d\n",
+                               snd_ctl_elem_id_get_name(id), snd_ctl_name(lhandle->ctl),
+                               snd_ctl_elem_id_get_device(id),
+                               snd_ctl_elem_id_get_subdevice(id));
+               return 0;
+       }
+}
+
+static int openctl_elem(struct loopback_handle *lhandle,
+                        int device, int subdevice,
+                        const char *name,
+                        snd_ctl_elem_value_t **elem)
+{
+       snd_ctl_elem_id_t *id;
+
+       snd_ctl_elem_id_alloca(&id);
+       snd_ctl_elem_id_set_device(id, device);
+       snd_ctl_elem_id_set_subdevice(id, subdevice);
+       snd_ctl_elem_id_set_name(id, name);
+       return openctl_elem_id(lhandle, id, elem);
+}
+
+static int openctl_elem_ascii(struct loopback_handle *lhandle, char *ascii_name,
+               snd_ctl_elem_value_t **elem)
+{
+       snd_ctl_elem_id_t *id;
+
+       snd_ctl_elem_id_alloca(&id);
+       if (snd_ctl_ascii_elem_id_parse(id, ascii_name)) {
+               fprintf(stderr, "Wrong control identifier: %s\n", ascii_name);
+               return -EINVAL;
        }
+       return openctl_elem_id(lhandle, id, elem);
 }
 
 static int openctl(struct loopback_handle *lhandle, int device, int subdevice)
@@ -1206,10 +1232,21 @@ static int openctl(struct loopback_handle *lhandle, int device, int subdevice)
 
        lhandle->ctl_rate_shift = NULL;
        if (lhandle->loopback->play == lhandle) {
+               // play only
+               if (lhandle->prateshift_name) {
+                       err = openctl_elem_ascii(lhandle, lhandle->prateshift_name,
+                                       &lhandle->ctl_rate_shift);
+                       if (err < 0) {
+                               logit(LOG_CRIT, "Unable to open playback PCM Rate Shift elem '%s'.\n",
+                                               lhandle->prateshift_name);
+                               exit(EXIT_FAILURE);
+                       }
+               }
                if (lhandle->loopback->controls)
                        goto __events;
                return 0;
        }
+       // capture only
        openctl_elem(lhandle, device, subdevice, "PCM Notify",
                        &lhandle->ctl_notify);
        openctl_elem(lhandle, device, subdevice, "PCM Rate Shift 100000",