Implements volume ramping

1 files changed, 144 insertions, 0 deletions

diff --git a/plugins/alsa/alsa-effect-ramp.c b/plugins/alsa/alsa-effect-ramp.c
new file mode 100644
index 0000000..c861d0e
--- /dev/null
+++ b/plugins/alsa/alsa-effect-ramp.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright(C) 2018 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http : //www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License
+
+for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * reference :
+ * https://github.com/zonque/simple-alsa-loop/blob/master/loop.c
+ * https://www.alsa-project.org/alsa-doc/alsa-lib/_2test_2pcm_8c-example.html#a31
+ *
+ */
+
+#define _GNU_SOURCE  // needed for vasprintf
+
+#include "alsa-softmixer.h"
+#include <pthread.h>
+#include <sys/syscall.h>
+
+typedef struct {
+    const char *uid;
+    long current; 
+    long target; 
+    int numid;
+    snd_ctl_t *ctlDev;
+    AlsaVolRampT *params;
+    sd_event_source *evtsrc; 
+    CtlSourceT *source;
+    sd_event *sdLoop;
+} VolRampHandleT;
+
+STATIC int VolRampTimerCB(sd_event_source* source, uint64_t timer, void* handle) {
+    VolRampHandleT *rampHandle = (VolRampHandleT*) handle;
+    int error;
+    uint64_t usec;
+
+    // RampDown
+    if (rampHandle->current > rampHandle->target) {
+        rampHandle->current = rampHandle->current - rampHandle->params->stepDown;
+        if (rampHandle->current < rampHandle->target) rampHandle->current = rampHandle->target;
+    }
+
+    // RampUp
+    if (rampHandle->current < rampHandle->target) {
+        rampHandle->current = rampHandle->current + rampHandle->params->stepUp;
+        if (rampHandle->current > rampHandle->target) rampHandle->current = rampHandle->target;
+    }
+    
+    error = AlsaCtlNumidSetLong(rampHandle->source, rampHandle->ctlDev, rampHandle->numid, rampHandle->current);
+    if (error) goto OnErrorExit;
+
+    // we reach target stop volram event
+    if (rampHandle->current == rampHandle->target) {
+        sd_event_source_unref(rampHandle->evtsrc);
+        snd_ctl_close (rampHandle->ctlDev);
+        free (rampHandle);
+    }
+    else {
+        // otherwise validate timer for a new run
+        sd_event_now(rampHandle->sdLoop, CLOCK_MONOTONIC, &usec);
+        sd_event_source_set_enabled(rampHandle->evtsrc, SD_EVENT_ONESHOT);
+        error = sd_event_source_set_time(rampHandle->evtsrc, usec + rampHandle->params->delay);
+    }
+
+    return 0;
+
+OnErrorExit:
+    AFB_ApiWarning(rampHandle->source->api, "VolRampTimerCB stream=%s numid=%d value=%ld", rampHandle->uid, rampHandle->numid, rampHandle->current);
+    sd_event_source_unref(source); // abandon volRamp
+    return -1;
+}
+
+PUBLIC int AlsaVolRampApply(CtlSourceT *source, AlsaSndLoopT *frontend, AlsaLoopStreamT *stream, AlsaVolRampT *ramp, json_object *volumeJ) {
+    long curvol, newvol;
+    const char*volString;
+    int error;
+    uint64_t usec;
+    
+    snd_ctl_t *ctlDev =AlsaCtlOpenCtl(source, frontend->cardid);
+    if (!ctlDev) goto OnErrorExit;
+            
+    error = AlsaCtlNumidGetLong(source, ctlDev, stream->volume, &curvol);
+    if (error) {
+        AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) Fail to get volume numid=%d", stream->uid, stream->volume);
+        goto OnErrorExit;
+    }
+
+    switch (json_object_get_type(volumeJ)) {
+        case json_type_string:
+            volString = json_object_get_string(volumeJ);
+            switch (volString[0]) {
+                case '+':
+                    sscanf(&volString[1], "%ld", &newvol);
+                    newvol = curvol + newvol;
+                    break;
+
+                case '-':
+                    sscanf(&volString[1], "%ld", &newvol);
+                    newvol = curvol - newvol;
+                    break;
+                default:
+                    AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) relative volume should start by '+|-' value=%s", stream->uid, json_object_get_string(volumeJ));
+                    goto OnErrorExit;
+            }
+            break;
+        case json_type_int:
+            newvol = json_object_get_int(volumeJ);
+            break;
+        default:
+            AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) volume should be string or integer value=%s", stream->uid, json_object_get_string(volumeJ));
+            goto OnErrorExit;
+
+    }
+
+    VolRampHandleT *rampHandle = calloc(1, sizeof (VolRampHandleT));
+    rampHandle->uid= stream->uid;
+    rampHandle->numid= stream->volume;
+    rampHandle->ctlDev= ctlDev;
+    rampHandle->source = source;
+    rampHandle->params = ramp;
+    rampHandle->target = newvol;
+    rampHandle->current= curvol;
+    rampHandle->sdLoop= stream->copy.sdLoop;
+    
+    // set a timer with ~250us accuracy
+    sd_event_now(rampHandle->sdLoop, CLOCK_MONOTONIC, &usec);
+    (void)sd_event_add_time(rampHandle->sdLoop, &rampHandle->evtsrc, CLOCK_MONOTONIC, usec+100, 250, VolRampTimerCB, rampHandle);
+
+    return 0;
+
+OnErrorExit:
+    return -1;
+}