From 2bd85e08cf1595cc8b7a856e5032dbc570f7df55 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Fri, 15 Mar 2024 17:24:27 +0100
Subject: [PATCH] gst: parse the audio rate from caps

Parse the audio rate from the caps and set this as the stream node.rate
property. This will try to switch the graph to this rate and avoids
resampling.

Rework some of the property handling.
---
 src/gst/gstpipewiresink.c | 40 +++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/src/gst/gstpipewiresink.c b/src/gst/gstpipewiresink.c
index 2b4592246..1abd4c2a0 100644
--- a/src/gst/gstpipewiresink.c
+++ b/src/gst/gstpipewiresink.c
@@ -595,14 +595,20 @@ gst_pipewire_sink_setcaps (GstBaseSink * bsink, GstCaps * caps)
   enum pw_stream_state state;
   const char *error = NULL;
   gboolean res = FALSE;
-  GstStructure *config;
+  GstStructure *config, *s;
   guint size;
   guint min_buffers;
   guint max_buffers;
   struct timespec abstime;
+  gint rate;
 
   pwsink = GST_PIPEWIRE_SINK (bsink);
 
+  s = gst_caps_get_structure (caps, 0);
+  rate = 0;
+  if (gst_structure_has_name (s, "audio/x-raw"))
+    gst_structure_get_int (s, "rate", &rate);
+
   possible = gst_caps_to_format_all (caps);
 
   pw_thread_loop_lock (pwsink->core->loop);
@@ -614,6 +620,9 @@ gst_pipewire_sink_setcaps (GstBaseSink * bsink, GstCaps * caps)
   if (state == PW_STREAM_STATE_UNCONNECTED) {
     enum pw_stream_flags flags;
     uint32_t target_id;
+    struct spa_dict_item items[3];
+    uint32_t n_items = 0;
+    char buf[64];
 
     flags = PW_STREAM_FLAG_ASYNC;
     if (pwsink->mode != GST_PIPEWIRE_SINK_MODE_PROVIDE)
@@ -624,25 +633,24 @@ gst_pipewire_sink_setcaps (GstBaseSink * bsink, GstCaps * caps)
     target_id = pwsink->path ? (uint32_t)atoi(pwsink->path) : PW_ID_ANY;
 
     if (pwsink->target_object) {
-      struct spa_dict_item items[2] = {
-        SPA_DICT_ITEM_INIT(PW_KEY_TARGET_OBJECT, pwsink->target_object),
-        /* XXX deprecated but the portal and some example apps only
-         * provide the object id */
-        SPA_DICT_ITEM_INIT(PW_KEY_NODE_TARGET, NULL),
-      };
-      struct spa_dict dict = SPA_DICT_INIT_ARRAY(items);
       uint64_t serial;
 
-      /* If target.object is a name, set it also to node.target */
-      if (spa_atou64(pwsink->target_object, &serial, 0)) {
-        dict.n_items = 1;
-      } else {
-        target_id = PW_ID_ANY;
-        items[1].value = pwsink->target_object;
-      }
+      items[n_items++] = SPA_DICT_ITEM_INIT(PW_KEY_TARGET_OBJECT, pwsink->target_object);
 
-      pw_stream_update_properties (pwsink->stream, &dict);
+      /* If target.object is a name, set it also to node.target */
+      if (!spa_atou64(pwsink->target_object, &serial, 0)) {
+        target_id = PW_ID_ANY;
+        /* XXX deprecated but the portal and some example apps only
+         * provide the object id */
+        items[n_items++] = SPA_DICT_ITEM_INIT(PW_KEY_NODE_TARGET, pwsink->target_object);
+      }
     }
+    if (rate != 0) {
+      snprintf(buf, sizeof(buf), "1/%u", rate);
+      items[n_items++] = SPA_DICT_ITEM_INIT(PW_KEY_NODE_RATE, buf);
+    }
+    if (n_items > 0)
+	    pw_stream_update_properties (pwsink->stream, &SPA_DICT_INIT(items, n_items));
 
     pw_stream_connect (pwsink->stream,
                           PW_DIRECTION_OUTPUT,