Merge branch 'wip/known-tags' into 'master'

Draft: pipewire: Introduce well known tags

See merge request pipewire/pipewire!2852

src/pipewire/meson.build

@@ -39,6 +39,7 @@ pipewire_headers = [
   'proxy.h',
   'resource.h',
   'stream.h',
+  'tags.h',
   'thread.h',
   'thread-loop.h',
   'timer-queue.h',

src/pipewire/tags.h

@@ -0,0 +1,48 @@
+/* PipeWire */
+/* SPDX-FileCopyrightText: Copyright © 2026 Red Hat */
+/* SPDX-License-Identifier: MIT */
+
+#ifndef PIPEWIRE_TAGS_H
+#define PIPEWIRE_TAGS_H
+
+#include <pipewire/utils.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \defgroup pw_stream_tags Well known stream tags
+ *
+ * A collection of tags that can be used for knows dynamic stream properties.
+ *
+ * \addtogroup pw_stream_tags
+ * \{
+ */
+
+/**
+ * Output tags, set by stream producers.
+ */
+
+/**< Stream contents should be considered to be scaled according to the
+ * specified floating point number. */
+#define PW_STREAM_OUTPUT_TAG_SCALE			"pipewire.output.stream.scale"
+
+
+/**
+ * Input tags, set by stream consumers.
+ */
+
+/**< Stream consumer prefers the producer produces content with the scale
+ * specified with this floating point number.
+*/
+#define PW_STREAM_INPUT_TAG_PREFERRED_SCALE		"pipewire.input.stream.preferred-scale"
+
+/** \}
+ */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PIPEWIRE_TAGS_H */