--- /dev/null
+/* GStreamer
+ * Copyright (C) 2021 Collabora Ltd.
+ * Author: Nicolas Dufresne <nicolas.dufresne@collabora.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstvideocodecalphameta.h"
+
+/**
+ * SECTION:gstvideocodecalphameta
+ * @title: GstVideoCodecAlphaMeta
+ * @short_description: GstMeta that can carry an extra buffer holding an
+ * encoded a frame whith luma that can be used as an alpha channel.
+ *
+ * This meta is primarily for internal use in GStreamer elements to support
+ * VP8/VP9 transparent video stored into WebM or Matroska containers, or
+ * transparent static AV1 images. Nothing prevents you from using this meta
+ * for custom purposes, but it generally can't be used to easily to add support
+ * for alpha channels to CODECs or formats that don't support that out of the
+ * box.
+ *
+ * Since: 1.20
+ */
+
+/**
+ * gst_video_codec_alpha_meta_api_get_type:
+ *
+ * Returns: #GType for the #GstVideoCodecAlphaMeta structure.
+ *
+ * Since: 1.20
+ */
+GType
+gst_video_codec_alpha_meta_api_get_type (void)
+{
+ static GType type = 0;
+ static const gchar *tags[] = { GST_META_TAG_VIDEO_STR, NULL };
+
+ if (g_once_init_enter (&type)) {
+ GType _type =
+ gst_meta_api_type_register ("GstVideoCodecAlphaMetaAPI", tags);
+ g_once_init_leave (&type, _type);
+ }
+ return type;
+}
+
+static gboolean
+gst_video_codec_alpha_meta_transform (GstBuffer * dest,
+ GstMeta * meta, GstBuffer * buffer, GQuark type, gpointer data)
+{
+ GstVideoCodecAlphaMeta *dmeta, *smeta;
+
+ smeta = (GstVideoCodecAlphaMeta *) meta;
+
+ if (GST_META_TRANSFORM_IS_COPY (type)) {
+ dmeta =
+ (GstVideoCodecAlphaMeta *) gst_buffer_add_meta (dest,
+ GST_VIDEO_CODEC_ALPHA_META_INFO, NULL);
+
+ if (!dmeta)
+ return FALSE;
+
+ dmeta->buffer = gst_buffer_ref (smeta->buffer);
+ }
+ return TRUE;
+}
+
+static gboolean
+gst_video_codec_alpha_meta_init (GstMeta * meta, gpointer params,
+ GstBuffer * buffer)
+{
+ GstVideoCodecAlphaMeta *ca_meta = (GstVideoCodecAlphaMeta *) meta;
+
+ /* the buffer ownership is transfered to the Meta */
+ ca_meta->buffer = (GstBuffer *) params;
+
+ return TRUE;
+}
+
+static void
+gst_video_codec_alpha_meta_free (GstMeta * meta, GstBuffer * buffer)
+{
+ GstVideoCodecAlphaMeta *ca_meta = (GstVideoCodecAlphaMeta *) meta;
+ gst_clear_buffer (&ca_meta->buffer);
+}
+
+/**
+ * gst_video_codec_alpha_meta_get_info:
+ *
+ * Returns: #GstMetaInfo pointer that describes #GstVideoCodecAlphaMeta.
+ *
+ * Since: 1.20
+ */
+const GstMetaInfo *
+gst_video_codec_alpha_meta_get_info (void)
+{
+ static const GstMetaInfo *info = NULL;
+
+ if (g_once_init_enter ((GstMetaInfo **) & info)) {
+ const GstMetaInfo *meta =
+ gst_meta_register (GST_VIDEO_CODEC_ALPHA_META_API_TYPE,
+ "GstVideoCodecAlphaMeta",
+ sizeof (GstVideoCodecAlphaMeta),
+ gst_video_codec_alpha_meta_init,
+ gst_video_codec_alpha_meta_free,
+ gst_video_codec_alpha_meta_transform);
+ g_once_init_leave ((GstMetaInfo **) & info, (GstMetaInfo *) meta);
+ }
+
+ return info;
+}
+
+/**
+ * gst_buffer_add_video_codec_alpha_meta:
+ * @buffer: (transfer none): a #GstBuffer
+ * @alpha_buffer: (transfer full): a #GstBuffer
+ *
+ * Attaches a #GstVideoCodecAlphaMeta metadata to @buffer with
+ * the given alpha buffer.
+ *
+ * Returns: (transfer none): the #GstVideoCodecAlphaMeta on @buffer.
+ *
+ * Since: 1.20
+ */
+GstVideoCodecAlphaMeta *
+gst_buffer_add_video_codec_alpha_meta (GstBuffer * buffer,
+ GstBuffer * alpha_buffer)
+{
+ GstVideoCodecAlphaMeta *meta;
+
+ g_return_val_if_fail (buffer != NULL, NULL);
+ g_return_val_if_fail (alpha_buffer != NULL, NULL);
+
+ meta =
+ (GstVideoCodecAlphaMeta *) gst_buffer_add_meta (buffer,
+ GST_VIDEO_CODEC_ALPHA_META_INFO, alpha_buffer);
+
+ return meta;
+}
--- /dev/null
+/* GStreamer
+ * Copyright (C) 2021 Collabora Ltd.
+ * Author: Nicolas Dufresne <nicolas.dufresne@collabora.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_VIDEO_CODEC_ALPHA_META_H__
+#define __GST_VIDEO_CODEC_ALPHA_META_H__
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+/**
+ * GST_VIDEO_CODEC_ALPHA_META_API_TYPE:
+ *
+ * Since: 1.20
+ */
+#define GST_VIDEO_CODEC_ALPHA_META_API_TYPE (gst_video_codec_alpha_meta_api_get_type())
+
+/**
+ * GST_VIDEO_CODEC_ALPHA_META_INFO:
+ *
+ * Since: 1.20
+ */
+#define GST_VIDEO_CODEC_ALPHA_META_INFO (gst_video_codec_alpha_meta_get_info())
+
+typedef struct _GstVideoCodecAlphaMeta GstVideoCodecAlphaMeta;
+
+/**
+ * GstVideoCodecAlphaMeta:
+ * @meta: parent #GstMeta
+ * @buffer: the encoded alpha frame
+ *
+ * Encapsulate an extra frame containing the encoded alpha channel for the
+ * currently negotiated CODEC. The streams must be of the same dimention as
+ * the original one.
+ *
+ * Since: 1.20
+ */
+struct _GstVideoCodecAlphaMeta
+{
+ GstMeta meta;
+
+ GstBuffer *buffer;
+};
+
+GST_VIDEO_API
+GType gst_video_codec_alpha_meta_api_get_type (void);
+
+GST_VIDEO_API
+const GstMetaInfo *gst_video_codec_alpha_meta_get_info (void);
+
+/**
+ * gst_buffer_get_video_codec_alpha_meta:
+ * @b: A #GstBuffer pointer, must be writable.
+ *
+ * Helper macro to get #GstVideoCodecAlphaMeta from an existing #GstBuffer.
+ *
+ * Returns: (nullable): the #GstVideoCodecAlphaMeta pointer, or %NULL if none.
+ *
+ * Since: 1.20
+ */
+#define gst_buffer_get_video_codec_alpha_meta(b) \
+ ((GstVideoCodecAlphaMeta *)gst_buffer_get_meta((b),GST_VIDEO_CODEC_ALPHA_META_API_TYPE))
+
+GST_VIDEO_API
+GstVideoCodecAlphaMeta *gst_buffer_add_video_codec_alpha_meta (GstBuffer * buffer,
+ GstBuffer * alpha_buffer);
+
+G_END_DECLS
+
+#endif /* __GST_VIDEO_CODEC_ALPHA_META_H__ */
projects / platform / upstream / gstreamer.git / commitdiff