v4l2codecs: Add initial formats helpers

sys/v4l2codecs/gstv4l2format.c

@@ -0,0 +1,77 @@
+/* GStreamer
+ * Copyright (C) 2020 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.
+ */
+
+#include "gstv4l2format.h"
+
+#define GST_CAT_DEFAULT gstv4l2codecs_debug
+GST_DEBUG_CATEGORY_EXTERN (gstv4l2codecs_debug);
+
+struct FormatEntry
+{
+  guint32 v4l2_pix_fmt;
+  gint num_planes;
+  GstVideoFormat gst_fmt;
+  guint bitdepth;
+  gint subsampling;
+};
+
+static struct FormatEntry format_map[] = {
+  {V4L2_PIX_FMT_NV12, 1, GST_VIDEO_FORMAT_NV12, 8, 420},
+  {0,}
+};
+
+static struct FormatEntry *
+lookup_v4l2_fmt (guint v4l2_pix_fmt)
+{
+  gint i;
+  struct FormatEntry *ret = NULL;
+
+  for (i = 0; format_map[i].v4l2_pix_fmt; i++) {
+    if (format_map[i].v4l2_pix_fmt == v4l2_pix_fmt) {
+      ret = format_map + i;
+      break;
+    }
+  }
+
+  return ret;
+}
+
+gboolean
+gst_v4l2_format_to_video_info (struct v4l2_format * fmt,
+    GstVideoInfo * out_info)
+{
+  struct FormatEntry *entry = lookup_v4l2_fmt (fmt->fmt.pix_mp.pixelformat);
+
+  if (!entry)
+    return FALSE;
+
+  if (entry->num_planes != 1) {
+    GST_FIXME ("Multi allocation formats are not supported yet");
+    return FALSE;
+  }
+
+  if (!gst_video_info_set_format (out_info, entry->gst_fmt,
+          fmt->fmt.pix_mp.width, fmt->fmt.pix_mp.height))
+    return FALSE;
+
+  /* FIXME play the extrapolation danse for single FDs formats, and copy over
+   * stride/offsets/size for the other formats */
+
+  return TRUE;
+}

sys/v4l2codecs/gstv4l2format.h

@@ -0,0 +1,30 @@
+/* GStreamer
+ * Copyright (C) 2020 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_V4L2_FORMAT_H__
+#define __GST_V4L2_FORMAT_H__
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include "linux/videodev2.h"
+
+gboolean   gst_v4l2_format_to_video_info (struct v4l2_format * fmt,
+                                          GstVideoInfo * out_info);
+
+#endif /* __GST_V4L2_FORMAT_H__ */

sys/v4l2codecs/meson.build

@@ -3,6 +3,7 @@ v4l2codecs_sources = [
   'gstv4l2codecdevice.c',
   'gstv4l2codech264dec.c',
   'gstv4l2decoder.c',
+  'gstv4l2format.c',
 ]
 
 libgudev_dep = dependency('gudev-1.0', required: get_option('v4l2codecs'))