videometa: API: Add GstVideoGLTextureUploadMeta

This allows elements to specify a function to upload
a buffer content to a specific OpenGL texture ID. It
could be used by the vaapi elements to provide a way
for eglglessink or WebKit to upload a VA surface to
an GL texture without the respective sinks knowing
anything about VA.

gst-libs/gst/video/gstvideometa.c

@@ -378,3 +378,92 @@ gst_video_meta_transform_scale_get_quark (void)
   }
   return _value;
 }
+
+
+GType
+gst_video_gl_texture_upload_meta_api_get_type (void)
+{
+  static volatile GType type = 0;
+  static const gchar *tags[] = { "memory", NULL };
+
+  if (g_once_init_enter (&type)) {
+    GType _type =
+        gst_meta_api_type_register ("GstVideoGLTextureUploadMetaAPI", tags);
+    g_once_init_leave (&type, _type);
+  }
+  return type;
+}
+
+static void
+gst_video_gl_texture_upload_meta_free (GstMeta * meta, GstBuffer * buffer)
+{
+  GstVideoGLTextureUploadMeta *vmeta = (GstVideoGLTextureUploadMeta *) meta;
+
+  if (vmeta->destroy_notify)
+    vmeta->destroy_notify (vmeta->user_data);
+}
+
+const GstMetaInfo *
+gst_video_gl_texture_upload_meta_get_info (void)
+{
+  static const GstMetaInfo *info = NULL;
+
+  if (g_once_init_enter (&info)) {
+    const GstMetaInfo *meta =
+        gst_meta_register (GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE,
+        "GstVideoGLTextureUploadMeta",
+        sizeof (GstVideoGLTextureUploadMeta),
+        NULL,
+        gst_video_gl_texture_upload_meta_free,
+        NULL);
+    g_once_init_leave (&info, meta);
+  }
+  return info;
+}
+
+/**
+ * gst_buffer_add_video_meta:
+ * @buffer: a #GstBuffer
+ * @flags: #GstVideoFrameFlags
+ * @format: a #GstVideoFormat
+ * @width: the width
+ * @height: the height
+ *
+ * Attaches GstVideoMeta metadata to @buffer with the given parameters and the
+ * default offsets and strides for @format and @width x @height.
+ *
+ * This function calculates the default offsets and strides and then calls
+ * gst_buffer_add_video_meta_full() with them.
+ *
+ * Returns: the #GstVideoMeta on @buffer.
+ */
+GstVideoGLTextureUploadMeta *
+gst_buffer_add_video_gl_texture_upload_meta (GstBuffer * buffer,
+    GstVideoGLTextureUpload upload, gpointer user_data,
+    GDestroyNotify destroy_notify)
+{
+  GstVideoGLTextureUploadMeta *meta;
+
+  g_return_val_if_fail (buffer != NULL, NULL);
+  g_return_val_if_fail (upload != NULL, NULL);
+
+  meta =
+      (GstVideoGLTextureUploadMeta *) gst_buffer_add_meta (buffer,
+      GST_VIDEO_GL_TEXTURE_UPLOAD_META_INFO, NULL);
+
+  meta->buffer = buffer;
+  meta->upload = upload;
+  meta->user_data = user_data;
+  meta->destroy_notify = destroy_notify;
+
+  return meta;
+}
+
+gboolean
+gst_video_gl_texture_upload_meta_upload (GstVideoGLTextureUploadMeta * meta,
+    guint format, guint texture_id)
+{
+  g_return_val_if_fail (meta != NULL, FALSE);
+
+  return meta->upload (meta, format, texture_id);
+}

gst-libs/gst/video/gstvideometa.h

@@ -138,6 +138,43 @@ typedef struct {
   GstVideoInfo *out_info;
 } GstVideoMetaTransform;
 
+#define GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE (gst_video_gl_texture_upload_meta_api_get_type())
+#define GST_VIDEO_GL_TEXTURE_UPLOAD_META_INFO  (gst_video_gl_texture_upload_meta_get_info())
+
+typedef struct _GstVideoGLTextureUploadMeta GstVideoGLTextureUploadMeta;
+typedef gboolean (*GstVideoGLTextureUpload) (GstVideoGLTextureUploadMeta *meta, guint format, guint texture_id);
+
+/**
+ * GstVideoGLTextureUploadMeta:
+ * @meta: parent #GstMeta
+ * @buffer: the buffer of this meta
+ * @upload: the function to upload the buffer to a specific texture ID
+ * @user_data: user data for the implementor of @upload
+ * @destroy_notify: #GDestroyNotify for destroying @user_data
+ *
+ * Extra buffer metadata for uploading a buffer to an OpenGL texture
+ * ID. The caller of gst_video_gl_texture_upload_meta_upload() must
+ * have OpenGL set up and call this from a thread where it is valid
+ * to upload something to an OpenGL texture.
+ */
+
+struct _GstVideoGLTextureUploadMeta {
+  GstMeta       meta;
+
+  GstBuffer *buffer;
+  GstVideoGLTextureUpload upload;
+
+  gpointer      user_data;
+  GDestroyNotify destroy_notify;
+};
+
+#define gst_buffer_get_video_gl_texture_upload_meta(b) ((GstVideoGLTextureUploadMeta*)gst_buffer_get_meta((b),GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE))
+GstVideoGLTextureUploadMeta * gst_buffer_add_video_gl_texture_upload_meta (GstBuffer *buffer, GstVideoGLTextureUpload upload, gpointer user_data, GDestroyNotify destroy_notify);
+gboolean gst_video_gl_texture_upload_meta_upload (GstVideoGLTextureUploadMeta *meta, guint format, guint texture_id);
+
+GType gst_video_gl_texture_upload_meta_api_get_type (void);
+const GstMetaInfo * gst_video_gl_texture_upload_meta_get_info (void);
+
 G_END_DECLS
 
 #endif /* __GST_VIDEO_META_H__ */