metavideo: first attempt at video metadata

Add a first version of video metadata for buffers that can contain more info
about the video such as strides and flags etc.

gst-libs/gst/video/Makefile.am

@@ -13,12 +13,12 @@ lib_LTLIBRARIES = libgstvideo-@GST_MAJORMINOR@.la
 CLEANFILES = $(BUILT_SOURCES)
 
 libgstvideo_@GST_MAJORMINOR@_la_SOURCES = \
-	video.c gstvideosink.c gstvideofilter.c convertframe.c
+	video.c gstvideosink.c gstvideofilter.c convertframe.c gstmetavideo.c
 nodist_libgstvideo_@GST_MAJORMINOR@_la_SOURCES = $(BUILT_SOURCES)
 
 libgstvideo_@GST_MAJORMINOR@includedir = $(includedir)/gstreamer-@GST_MAJORMINOR@/gst/video
 libgstvideo_@GST_MAJORMINOR@include_HEADERS = \
-	video.h gstvideosink.h gstvideofilter.h
+	video.h gstvideosink.h gstvideofilter.h gstmetavideo.h
 nodist_libgstvideo_@GST_MAJORMINOR@include_HEADERS = $(built_headers)
 
 libgstvideo_@GST_MAJORMINOR@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS)

gst-libs/gst/video/gstmetavideo.c

@@ -0,0 +1,166 @@
+/* GStreamer
+ * Copyright (C) <2011> Wim Taymans <wim.taymans@gmail.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "gstmetavideo.h"
+
+/* video metadata */
+const GstMetaInfo *
+gst_meta_video_get_info (void)
+{
+  static const GstMetaInfo *meta_video_info = NULL;
+
+  if (meta_video_info == NULL) {
+    meta_video_info = gst_meta_register ("GstMetaVideo", "GstMetaVideo",
+        sizeof (GstMetaVideo),
+        (GstMetaInitFunction) NULL,
+        (GstMetaFreeFunction) NULL,
+        (GstMetaCopyFunction) NULL,
+        (GstMetaTransformFunction) NULL,
+        (GstMetaSerializeFunction) NULL, (GstMetaDeserializeFunction) NULL);
+  }
+  return meta_video_info;
+}
+
+
+GstMetaVideo *
+gst_buffer_add_meta_video (GstBuffer * buffer, GstMetaVideoFlags flags,
+    GstVideoFormat format, guint width, guint height)
+{
+  GstMetaVideo *meta;
+  guint i;
+  GstMetaVideoPlane plane[GST_VIDEO_MAX_PLANES];
+
+  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++) {
+    gint offset;
+
+    offset = gst_video_format_get_component_offset (format, i, width, height);
+    /* end when the offset is 0 for something else that the first component */
+    if (i > 0 && offset == 0)
+      break;
+
+    plane[i].offset = offset;
+    plane[i].stride = gst_video_format_get_row_stride (format, i, width);
+  }
+
+  meta = gst_buffer_add_meta_video_full (buffer, flags, format, width, height,
+      i, plane);
+
+  return meta;
+}
+
+GstMetaVideo *
+gst_buffer_add_meta_video_full (GstBuffer * buffer, GstMetaVideoFlags flags,
+    GstVideoFormat format, guint width, guint height,
+    guint n_planes, GstMetaVideoPlane plane[GST_VIDEO_MAX_PLANES])
+{
+  GstMetaVideo *meta;
+  guint i;
+
+  meta =
+      (GstMetaVideo *) gst_buffer_add_meta (buffer, GST_META_INFO_VIDEO, NULL);
+
+  meta->flags = flags;
+  meta->format = format;
+  meta->width = width;
+  meta->height = height;
+
+  meta->n_planes = n_planes;
+  for (i = 0; i < n_planes; i++)
+    meta->plane[i] = plane[i];
+
+  return meta;
+}
+
+static GstMemory *
+find_mem_for_offset (GstBuffer * buffer, guint * offset, GstMapFlags flags)
+{
+  guint n, i;
+  GstMemory *res = NULL;
+
+  n = gst_buffer_n_memory (buffer);
+  for (i = 0; i < n; i++) {
+    GstMemory *mem = NULL;
+    gsize size;
+
+    mem = gst_buffer_peek_memory (buffer, i, flags);
+    size = gst_memory_get_sizes (mem, NULL);
+
+    if (*offset < size) {
+      res = mem;
+      break;
+    }
+    *offset -= size;
+  }
+  return res;
+}
+
+gpointer
+gst_meta_video_map (GstMetaVideo * meta, guint plane, gint * stride,
+    GstMapFlags flags)
+{
+  guint offset;
+  gboolean write;
+  GstBuffer *buffer;
+  GstMemory *mem;
+  guint8 *base;
+
+  g_return_val_if_fail (meta != NULL, NULL);
+  g_return_val_if_fail (plane < meta->n_planes, NULL);
+  g_return_val_if_fail (stride != NULL, NULL);
+
+  buffer = meta->buffer;
+  g_return_val_if_fail (buffer != NULL, NULL);
+
+  write = (flags & GST_MAP_WRITE) != 0;
+  g_return_val_if_fail (write && !gst_buffer_is_writable (buffer), NULL);
+
+  offset = meta->plane[plane].offset;
+  *stride = meta->plane[plane].stride;
+  /* find the memory block for this plane, this is the memory block containing
+   * the plane offset */
+  mem = find_mem_for_offset (buffer, &offset, flags);
+
+  /* move to the right offset inside the block */
+  base = gst_memory_map (mem, NULL, NULL, flags);
+
+  return base + offset;
+}
+
+gboolean
+gst_meta_video_unmap (GstMetaVideo * meta, guint plane, gpointer data)
+{
+  guint offset;
+  GstBuffer *buffer;
+  GstMemory *mem;
+  guint8 *base;
+
+  g_return_val_if_fail (meta != NULL, FALSE);
+  g_return_val_if_fail (plane < meta->n_planes, FALSE);
+
+  buffer = meta->buffer;
+  g_return_val_if_fail (buffer != NULL, FALSE);
+
+  offset = meta->plane[plane].offset;
+  mem = find_mem_for_offset (buffer, &offset, GST_MAP_READ);
+  base = data;
+
+  gst_memory_unmap (mem, base - offset, -1);
+
+  return TRUE;
+}

gst-libs/gst/video/gstmetavideo.h

@@ -0,0 +1,105 @@
+/* GStreamer
+ * Copyright (C) <2011> Wim Taymans <wim.taymans@gmail.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_META_VIDEO_H__
+#define __GST_META_VIDEO_H__
+
+#include <gst/gst.h>
+
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+#define GST_META_INFO_VIDEO  (gst_meta_video_get_info())
+
+#define GST_VIDEO_MAX_PLANES 4
+
+typedef struct _GstMetaVideo GstMetaVideo;
+typedef struct _GstMetaVideoPlane GstMetaVideoPlane;
+
+/**
+ * GstMetaVideoFlags:
+ * @GST_META_VIDEO_FLAG_NONE: no flags
+ *
+ * Extra video flags
+ */
+typedef enum {
+  GST_META_VIDEO_FLAG_NONE = 0
+} GstMetaVideoFlags;
+
+/**
+ * GstMetaVideoPlane:
+ * @offset: offset of the first pixel in the buffer memory region
+ * @stride: stride of the image lines. Can be negative when the image is
+ *    upside-down
+ *
+ * Information for one video plane.
+ */
+struct _GstMetaVideoPlane {
+  gsize           offset;
+  gint            stride;
+};
+
+/**
+ * GstMetaVideo:
+ * @meta: parent #GstMeta
+ * @flags: additional video flags
+ * @n_planes: the number of planes in the image
+ * @plane: array of #GstMetaVideoPlane
+ * @map: map the memory of a plane
+ * @unmap: unmap the memory of a plane
+ *
+ * Extra buffer metadata describing image properties
+ */
+struct _GstMetaVideo {
+  GstMeta       meta;
+
+  GstMetaVideoFlags  flags;
+
+  GstBuffer         *buffer;
+
+  GstVideoFormat     format;
+  guint              width;
+  guint              height;
+
+  guint              n_planes;
+  GstMetaVideoPlane  plane[GST_VIDEO_MAX_PLANES];
+
+  gpointer (*map)    (GstMetaVideo *meta, guint plane, gint *stride,
+                      GstMapFlags flags);
+  gboolean (*unmap)  (GstMetaVideo *meta, guint plane, gpointer data);
+};
+
+const GstMetaInfo * gst_meta_video_get_info (void);
+
+#define gst_buffer_get_meta_video(b) ((GstMetaVideo*)gst_buffer_get_meta((b),GST_META_INFO_VIDEO))
+GstMetaVideo * gst_buffer_add_meta_video       (GstBuffer *buffer, GstMetaVideoFlags flags,
+                                                GstVideoFormat format, guint width, guint height);
+GstMetaVideo * gst_buffer_add_meta_video_full  (GstBuffer *buffer, GstMetaVideoFlags flags,
+                                                GstVideoFormat format, guint width, guint height,
+                                                guint n_planes, GstMetaVideoPlane plane[GST_VIDEO_MAX_PLANES]);
+
+gpointer       gst_meta_video_map        (GstMetaVideo *meta, guint plane, gint *stride,
+                                          GstMapFlags flags);
+gboolean       gst_meta_video_unmap      (GstMetaVideo *meta, guint plane, gpointer data);
+
+
+G_END_DECLS
+
+#endif /* __GST_META_VIDEO_H__ */