gstreamer/subprojects/gstreamer-vaapi/gst/vaapi/gstvaapipluginbase.c

/*
 *  gstvaapipluginbase.c - Base GStreamer VA-API Plugin element
 *
 *  Copyright (C) 2010-2011 Splitted-Desktop Systems
 *    Author: Gwenole Beauchesne <gwenole.beauchesne@splitted-desktop.com>
 *  Copyright (C) 2011-2014 Intel Corporation
 *    Author: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2.1
 *  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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301 USA
 */

#include "gstcompat.h"
#include <gst/vaapi/gstvaapisurface_drm.h>
#include <gst/base/gstpushsrc.h>
#include "gstvaapipluginbase.h"
#include "gstvaapipluginutil.h"
#include "gstvaapivideocontext.h"
#include "gstvaapivideometa.h"
#include "gstvaapivideobufferpool.h"
#if USE_GST_GL_HELPERS
# include <gst/gl/gl.h>
#endif

GST_DEBUG_CATEGORY_STATIC (CAT_PERFORMANCE);
/* Default debug category is from the subclass */
#define GST_CAT_DEFAULT (plugin->debug_category)

#define BUFFER_POOL_SINK_MIN_BUFFERS 2

#define GST_VAAPI_PAD_PRIVATE(pad) \
  (GST_VAAPI_PLUGIN_BASE_GET_CLASS(plugin)->get_vaapi_pad_private(plugin, pad))

GstVaapiPadPrivate *
gst_vaapi_pad_private_new (void)
{
  GstVaapiPadPrivate *priv = g_new0 (GstVaapiPadPrivate, 1);

  gst_video_info_init (&priv->info);

  return priv;
}

void
gst_vaapi_pad_private_reset (GstVaapiPadPrivate * priv)
{
  g_assert (priv);

  gst_caps_replace (&priv->caps, NULL);
  gst_video_info_init (&priv->info);

  gst_clear_object (&priv->buffer_pool);
  gst_clear_object (&priv->allocator);

  priv->buffer_size = 0;
  priv->caps_is_raw = FALSE;

  gst_clear_object (&priv->other_allocator);
}

void
gst_vaapi_pad_private_finalize (GstVaapiPadPrivate * priv)
{
  gst_vaapi_pad_private_reset (priv);
  g_free (priv);
}

/* GstVideoContext interface */
static void
plugin_set_display (GstVaapiPluginBase * plugin, GstVaapiDisplay * display)
{
  const gchar *const display_name =
      gst_vaapi_display_get_display_name (display);

  if (plugin->display_name && g_strcmp0 (plugin->display_name, display_name)) {
    GST_DEBUG_OBJECT (plugin, "incompatible display name '%s', requested '%s'",
        display_name, plugin->display_name);
    gst_vaapi_display_replace (&plugin->display, NULL);
  } else {
    GST_INFO_OBJECT (plugin, "set display %" GST_PTR_FORMAT, display);
    gst_vaapi_display_replace (&plugin->display, display);
    plugin->display_type = gst_vaapi_display_get_display_type (display);
    gst_vaapi_plugin_base_set_display_name (plugin, display_name);
  }
  gst_object_unref (display);
}

/**
 * gst_vaapi_plugin_base_set_context:
 * @plugin: a #GstVaapiPluginBase instance
 * @context: a #GstContext to set
 *
 * This is a common set_context() element's vmethod for all the
 * GStreamer VA-API elements.
 *
 * It normally should be used through the macro
 * #GST_VAAPI_PLUGIN_BASE_DEFINE_SET_CONTEXT()
 **/
void
gst_vaapi_plugin_base_set_context (GstVaapiPluginBase * plugin,
    GstContext * context)
{
  GstVaapiDisplay *display = NULL;

  /* gst.vaapi.app.Display is only attended _if_ the element is
   * vaapisink and it doesn't have a display set yet */
  if (gst_vaapi_video_context_get_display (context,
          GST_IS_VIDEO_SINK (plugin) && !plugin->display, &display)) {
    plugin_set_display (plugin, display);
  }
#if USE_GST_GL_HELPERS
  gst_gl_handle_set_context (GST_ELEMENT_CAST (plugin), context,
      (GstGLDisplay **) & plugin->gl_display,
      (GstGLContext **) & plugin->gl_other_context);
#endif
}

void
gst_vaapi_plugin_base_init_interfaces (GType g_define_type_id)
{
}

static gboolean
default_has_interface (GstVaapiPluginBase * plugin, GType type)
{
  return FALSE;
}

static void
default_display_changed (GstVaapiPluginBase * plugin)
{
}

static GstVaapiSurface *
_get_cached_surface (GstBuffer * buf)
{
  return gst_mini_object_get_qdata (GST_MINI_OBJECT (buf),
      g_quark_from_static_string ("GstVaapiDMABufSurface"));
}

static void
_set_cached_surface (GstBuffer * buf, GstVaapiSurface * surface)
{
  return gst_mini_object_set_qdata (GST_MINI_OBJECT (buf),
      g_quark_from_static_string ("GstVaapiDMABufSurface"), surface,
      (GDestroyNotify) gst_vaapi_surface_unref);
}

static gboolean
plugin_update_sinkpad_info_from_buffer (GstVaapiPluginBase * plugin,
    GstPad * sinkpad, GstBuffer * buf)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstVideoInfo *const vip = &sinkpriv->info;
  GstVideoMeta *vmeta;
  guint i;

  vmeta = gst_buffer_get_video_meta (buf);
  if (!vmeta)
    return TRUE;

  if (GST_VIDEO_INFO_FORMAT (vip) != vmeta->format ||
      GST_VIDEO_INFO_WIDTH (vip) != vmeta->width ||
      GST_VIDEO_INFO_HEIGHT (vip) != vmeta->height ||
      GST_VIDEO_INFO_N_PLANES (vip) != vmeta->n_planes)
    return FALSE;

  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (vip); ++i) {
    GST_VIDEO_INFO_PLANE_OFFSET (vip, i) = vmeta->offset[i];
    GST_VIDEO_INFO_PLANE_STRIDE (vip, i) = vmeta->stride[i];
  }
  GST_VIDEO_INFO_SIZE (vip) = gst_buffer_get_size (buf);
  return TRUE;
}

static gboolean
is_dma_buffer (GstBuffer * buf)
{
  GstMemory *mem;

  if (gst_buffer_n_memory (buf) < 1)
    return FALSE;

  mem = gst_buffer_peek_memory (buf, 0);
  if (!mem || !gst_is_dmabuf_memory (mem))
    return FALSE;
  return TRUE;
}

static gboolean
plugin_bind_dma_to_vaapi_buffer (GstVaapiPluginBase * plugin, GstPad * sinkpad,
    GstBuffer * inbuf, GstBuffer * outbuf)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstVideoInfo *const vip = &sinkpriv->info;
  GstVaapiVideoMeta *meta;
  GstVaapiSurface *surface;
  GstVaapiSurfaceProxy *proxy;
  gint fd;

  fd = gst_dmabuf_memory_get_fd (gst_buffer_peek_memory (inbuf, 0));
  if (fd < 0)
    return FALSE;

  if (!plugin_update_sinkpad_info_from_buffer (plugin, sinkpad, inbuf))
    goto error_update_sinkpad_info;

  meta = gst_buffer_get_vaapi_video_meta (outbuf);
  g_return_val_if_fail (meta != NULL, FALSE);

  /* Check for a VASurface cached in the buffer */
  surface = _get_cached_surface (inbuf);
  if (!surface) {
    /* otherwise create one and cache it */
    surface =
        gst_vaapi_surface_new_with_dma_buf_handle (plugin->display, fd, vip);
    if (!surface)
      goto error_create_surface;
    _set_cached_surface (inbuf, surface);
  }

  proxy = gst_vaapi_surface_proxy_new (surface);
  if (!proxy)
    goto error_create_proxy;
  gst_vaapi_video_meta_set_surface_proxy (meta, proxy);
  gst_vaapi_surface_proxy_unref (proxy);
  gst_buffer_add_parent_buffer_meta (outbuf, inbuf);
  return TRUE;

  /* ERRORS */
error_update_sinkpad_info:
  {
    GST_ERROR_OBJECT (plugin,
        "failed to update sink pad video info from video meta");
    return FALSE;
  }
error_create_surface:
  {
    GST_ERROR_OBJECT (plugin,
        "failed to create VA surface from dma_buf handle");
    return FALSE;
  }
error_create_proxy:
  {
    GST_ERROR_OBJECT (plugin,
        "failed to create VA surface proxy from wrapped VA surface");
    return FALSE;
  }
}

static void
plugin_reset_texture_map (GstVaapiPluginBase * plugin)
{
  if (plugin->display)
    gst_vaapi_display_reset_texture_map (plugin->display);
}

static GstVaapiPadPrivate *
default_get_vaapi_pad_private (GstVaapiPluginBase * plugin, GstPad * pad)
{
  if (plugin->sinkpad == pad)
    return plugin->sinkpriv;

  g_assert (plugin->srcpad == pad);
  return plugin->srcpriv;
}

void
gst_vaapi_plugin_base_class_init (GstVaapiPluginBaseClass * klass)
{
  klass->has_interface = default_has_interface;
  klass->display_changed = default_display_changed;
  klass->get_vaapi_pad_private = default_get_vaapi_pad_private;
}

void
gst_vaapi_plugin_base_init (GstVaapiPluginBase * plugin,
    GstDebugCategory * debug_category)
{
  plugin->debug_category = debug_category;
  plugin->display_type = GST_VAAPI_DISPLAY_TYPE_ANY;
  plugin->display_type_req = GST_VAAPI_DISPLAY_TYPE_ANY;

  /* sink pad */
  plugin->sinkpad = gst_element_get_static_pad (GST_ELEMENT (plugin), "sink");

  if (plugin->sinkpad)
    plugin->sinkpriv = gst_vaapi_pad_private_new ();

  /* src pad */
  if (!(GST_OBJECT_FLAGS (plugin) & GST_ELEMENT_FLAG_SINK))
    plugin->srcpad = gst_element_get_static_pad (GST_ELEMENT (plugin), "src");

  if (plugin->srcpad)
    plugin->srcpriv = gst_vaapi_pad_private_new ();

  plugin->enable_direct_rendering =
      (g_getenv ("GST_VAAPI_ENABLE_DIRECT_RENDERING") != NULL);
}

void
gst_vaapi_plugin_base_finalize (GstVaapiPluginBase * plugin)
{
  gst_vaapi_plugin_base_close (plugin);
  gst_vaapi_display_replace (&plugin->display, NULL);
  g_free (plugin->display_name);

  if (plugin->sinkpriv)
    gst_vaapi_pad_private_finalize (plugin->sinkpriv);
  if (plugin->srcpriv)
    gst_vaapi_pad_private_finalize (plugin->srcpriv);

  if (plugin->sinkpad)
    gst_object_unref (plugin->sinkpad);
  if (plugin->srcpad)
    gst_object_unref (plugin->srcpad);
}

/**
 * gst_vaapi_plugin_base_open:
 * @plugin: a #GstVaapiPluginBase
 *
 * Allocates any internal resources needed for correct operation from
 * the subclass.
 *
 * Returns: %TRUE if successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_open (GstVaapiPluginBase * plugin)
{
  gst_caps_replace (&plugin->allowed_raw_caps, NULL);
  return TRUE;
}

/**
 * gst_vaapi_plugin_base_close:
 * @plugin: a #GstVaapiPluginBase
 *
 * Deallocates all internal resources that were allocated so
 * far. i.e. put the base plugin object into a clean state.
 */
void
gst_vaapi_plugin_base_close (GstVaapiPluginBase * plugin)
{
  /* Release vaapi textures first if exist, which refs display object */
  plugin_reset_texture_map (plugin);

  gst_object_replace (&plugin->gl_context, NULL);
  gst_object_replace (&plugin->gl_display, NULL);
  gst_object_replace (&plugin->gl_other_context, NULL);

  gst_caps_replace (&plugin->allowed_raw_caps, NULL);

  if (plugin->sinkpriv)
    gst_vaapi_pad_private_reset (plugin->sinkpriv);
  if (plugin->srcpriv)
    gst_vaapi_pad_private_reset (plugin->srcpriv);
}

/**
 * gst_vaapi_plugin_base_has_display_type:
 * @plugin: a #GstVaapiPluginBase
 * @display_type_req: the desired #GstVaapiDisplayType
 *
 * Checks whether the @plugin elements already has a #GstVaapiDisplay
 * instance compatible with type @display_type_req.
 *
 * Return value: %TRUE if @plugin has a compatible display, %FALSE otherwise
 */
gboolean
gst_vaapi_plugin_base_has_display_type (GstVaapiPluginBase * plugin,
    GstVaapiDisplayType display_type_req)
{
  GstVaapiDisplayType display_type;

  if (!plugin->display)
    return FALSE;

  display_type = plugin->display_type;
  if (gst_vaapi_display_type_is_compatible (display_type, display_type_req))
    return TRUE;

  display_type = gst_vaapi_display_get_class_type (plugin->display);
  if (gst_vaapi_display_type_is_compatible (display_type, display_type_req))
    return TRUE;
  return FALSE;
}

/**
 * gst_vaapi_plugin_base_set_display_type:
 * @plugin: a #GstVaapiPluginBase
 * @display_type: the new request #GstVaapiDisplayType
 *
 * Requests a new display type. The change is effective at the next
 * call to gst_vaapi_plugin_base_ensure_display().
 */
void
gst_vaapi_plugin_base_set_display_type (GstVaapiPluginBase * plugin,
    GstVaapiDisplayType display_type)
{
  plugin->display_type_req = display_type;
}

/**
 * gst_vaapi_plugin_base_set_display_name:
 * @plugin: a #GstVaapiPluginBase
 * @display_name: the new display name to match
 *
 * Sets the name of the display to look for. The change is effective
 * at the next call to gst_vaapi_plugin_base_ensure_display().
 */
void
gst_vaapi_plugin_base_set_display_name (GstVaapiPluginBase * plugin,
    const gchar * display_name)
{
  g_free (plugin->display_name);
  plugin->display_name = g_strdup (display_name);
}

/**
 * gst_vaapi_plugin_base_ensure_display:
 * @plugin: a #GstVaapiPluginBase
 *
 * Ensures the display stored in @plugin complies with the requested
 * display type constraints.
 *
 * Returns: %TRUE if the display was created to match the requested
 *   type, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_ensure_display (GstVaapiPluginBase * plugin)
{
  if (gst_vaapi_plugin_base_has_display_type (plugin, plugin->display_type_req))
    return TRUE;
  gst_vaapi_display_replace (&plugin->display, NULL);

  if (!gst_vaapi_ensure_display (GST_ELEMENT (plugin),
          plugin->display_type_req))
    return FALSE;
  plugin->display_type = gst_vaapi_display_get_display_type (plugin->display);

  GST_VAAPI_PLUGIN_BASE_GET_CLASS (plugin)->display_changed (plugin);
  return TRUE;
}

static gboolean
gst_vaapi_buffer_pool_caps_is_equal (GstBufferPool * pool, GstCaps * newcaps)
{
  GstStructure *config;
  GstCaps *caps;
  gboolean ret;

  caps = NULL;
  ret = FALSE;
  config = gst_buffer_pool_get_config (pool);
  if (gst_buffer_pool_config_get_params (config, &caps, NULL, NULL, NULL))
    ret = gst_caps_is_equal (newcaps, caps);
  gst_structure_free (config);

  return ret;
}

static inline gboolean
reset_allocator (GstAllocator * allocator, GstVideoInfo * vinfo)
{
  const GstVideoInfo *orig_vi;

  if (!allocator)
    return TRUE;

  orig_vi = gst_allocator_get_vaapi_video_info (allocator, NULL);
  if (!gst_video_info_changed (orig_vi, vinfo))
    return FALSE;

  gst_object_unref (allocator);
  return TRUE;
}

static gboolean
ensure_sinkpad_allocator (GstVaapiPluginBase * plugin, GstPad * sinkpad,
    GstCaps * caps, guint * size)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstVideoInfo vinfo;
  const GstVideoInfo *image_info;
  GstVaapiImageUsageFlags usage_flag =
      GST_VAAPI_IMAGE_USAGE_FLAG_NATIVE_FORMATS;

  if (!gst_video_info_from_caps (&vinfo, caps))
    goto error_invalid_caps;

  if (!reset_allocator (sinkpriv->allocator, &vinfo))
    goto bail;

  /* enable direct upload if upstream requests raw video */
  if (gst_caps_is_video_raw (caps)) {
    usage_flag = GST_VAAPI_IMAGE_USAGE_FLAG_DIRECT_UPLOAD;
    GST_INFO_OBJECT (plugin, "enabling direct upload in sink allocator");
  }
  sinkpriv->allocator =
      gst_vaapi_video_allocator_new (plugin->display, &vinfo, 0, usage_flag);

bail:
  if (!sinkpriv->allocator)
    goto error_create_allocator;

  image_info = gst_allocator_get_vaapi_video_info (sinkpriv->allocator, NULL);
  g_assert (image_info);        /* allocator ought set its image info */

  /* update the size with the one generated by the allocator */
  *size = GST_VIDEO_INFO_SIZE (image_info);

  return TRUE;

  /* ERRORS */
error_invalid_caps:
  {
    GST_ERROR_OBJECT (plugin, "invalid caps %" GST_PTR_FORMAT, caps);
    return FALSE;
  }
error_create_allocator:
  {
    GST_ERROR_OBJECT (plugin, "failed to create sink pad's allocator");
    return FALSE;
  }
}

static inline guint
get_dmabuf_surface_allocation_flags (void)
{
  /* @FIXME: fetch the real devices ids */
  /* Pair vendor/device identifies an unique physical device. */
  guint va_vendor_id = 0x00;
  guint va_device_id = 0x00;
  guint gl_vendor_id = 0x00;
  guint gl_device_id = 0x00;

  /* Requires linear memory only if fd export is done on a different
   * device than the device where the fd is imported. */
  gboolean same_physical_device = va_vendor_id == gl_vendor_id
      && va_device_id == gl_device_id;

  if (same_physical_device)
    return 0;
  return GST_VAAPI_SURFACE_ALLOC_FLAG_LINEAR_STORAGE;
}

static inline GstAllocator *
create_dmabuf_srcpad_allocator (GstVaapiPluginBase * plugin,
    GstVideoInfo * vinfo, gboolean check_for_map)
{
  GstAllocator *allocator;

  if (!GST_IS_VIDEO_DECODER (plugin) && !GST_IS_BASE_TRANSFORM (plugin))
    return NULL;

  allocator = gst_vaapi_dmabuf_allocator_new (plugin->display, vinfo,
      get_dmabuf_surface_allocation_flags (), GST_PAD_SRC);
  if (!allocator || !check_for_map)
    return allocator;

  /* the dmabuf allocator *must* be capable to map a buffer with raw
   * caps and the there's no evidence of downstream dmabuf
   * importation */
  if (!gst_vaapi_dmabuf_can_map (plugin->display, allocator)) {
    GST_INFO_OBJECT (plugin, "dmabuf allocator generates unmappable buffers");
    gst_object_replace ((GstObject **) & allocator, NULL);
  }

  return allocator;
}

static gboolean
ensure_srcpad_allocator (GstVaapiPluginBase * plugin, GstPad * srcpad,
    GstVideoInfo * vinfo, GstCaps * caps)
{
  GstVaapiPadPrivate *srcpriv = GST_VAAPI_PAD_PRIVATE (srcpad);
  const GstVideoInfo *image_info;

  if (!reset_allocator (srcpriv->allocator, vinfo))
    goto valid_allocator;

  srcpriv->allocator = NULL;
  if (caps && gst_vaapi_caps_feature_contains (caps,
          GST_VAAPI_CAPS_FEATURE_DMABUF)) {
    srcpriv->allocator = create_dmabuf_srcpad_allocator (plugin, vinfo, FALSE);
    if (!srcpriv->allocator)
      goto error_create_allocator;
  }

  if (!srcpriv->allocator) {
    GstVaapiImageUsageFlags usage_flag =
        GST_VAAPI_IMAGE_USAGE_FLAG_NATIVE_FORMATS;

    if (plugin->enable_direct_rendering) {
      usage_flag = GST_VAAPI_IMAGE_USAGE_FLAG_DIRECT_RENDER;
      GST_INFO_OBJECT (plugin, "enabling direct rendering in source allocator");
    }

    srcpriv->allocator =
        gst_vaapi_video_allocator_new (plugin->display, vinfo, 0, usage_flag);
  }

  if (!srcpriv->allocator)
    goto error_create_allocator;

valid_allocator:
  image_info = gst_allocator_get_vaapi_video_info (srcpriv->allocator, NULL);
  g_assert (image_info);        /* both allocators ought set its image
                                 * info */

  /* update the size with the one generated by the allocator */
  GST_VIDEO_INFO_SIZE (vinfo) = GST_VIDEO_INFO_SIZE (image_info);

  if (GST_IS_VIDEO_DECODER (plugin)) {
    /* the received caps are the "allocation caps" which may be
     * different from the "negotiation caps". In this case, we should
     * indicate the allocator to store the negotiation caps since they
     * are the one should be used for frame mapping with GstVideoMeta */
    gboolean different_caps = srcpriv->caps &&
        !gst_caps_is_strictly_equal (srcpriv->caps, caps);
    const GstVideoInfo *previous_negotiated =
        gst_allocator_get_vaapi_negotiated_video_info (srcpriv->allocator);

    if (different_caps) {
      guint i;
      GstVideoInfo vi = srcpriv->info;

      /* update the planes and the size with the allocator image/surface
       * info, but not the resolution */
      for (i = 0; i < GST_VIDEO_INFO_N_PLANES (image_info); i++) {
        GST_VIDEO_INFO_PLANE_OFFSET (&vi, i) =
            GST_VIDEO_INFO_PLANE_OFFSET (image_info, i);
        GST_VIDEO_INFO_PLANE_STRIDE (&vi, i) =
            GST_VIDEO_INFO_PLANE_STRIDE (image_info, i);
      }
      GST_VIDEO_INFO_SIZE (&vi) = GST_VIDEO_INFO_SIZE (image_info);
      gst_allocator_set_vaapi_negotiated_video_info (srcpriv->allocator, &vi);
    } else if (previous_negotiated) {
      gst_allocator_set_vaapi_negotiated_video_info (srcpriv->allocator, NULL);
    }
  }
  return TRUE;

  /* ERRORS */
error_create_allocator:
  {
    GST_ERROR_OBJECT (plugin, "failed to create src pad's allocator");
    return FALSE;
  }
}

/**
 * gst_vaapi_plugin_base_create_pool:
 * @plugin: a #GstVaapiPluginBase
 * @caps: the initial #GstCaps for the resulting buffer pool
 * @size: the size of each buffer, not including prefix and padding
 * @options: a set of #GstVaapiVideoBufferPoolOption encoded as bit-wise
 * @allocator: (allow-none): the #GstAllocator to use or %NULL
 *
 * Create an instance of #GstVaapiVideoBufferPool
 *
 * Returns: (transfer full): a new allocated #GstBufferPool
 **/
static GstBufferPool *
gst_vaapi_plugin_base_create_pool (GstVaapiPluginBase * plugin, GstCaps * caps,
    gsize size, guint min_buffers, guint max_buffers, guint options,
    GstAllocator * allocator)
{
  GstBufferPool *pool;
  GstStructure *config;

  if (!(pool = gst_vaapi_video_buffer_pool_new (plugin->display)))
    goto error_create_pool;

  config = gst_buffer_pool_get_config (pool);
  gst_buffer_pool_config_set_params (config, caps, size, min_buffers,
      max_buffers);
  gst_buffer_pool_config_add_option (config,
      GST_BUFFER_POOL_OPTION_VAAPI_VIDEO_META);
  if (options & GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META) {
    gst_buffer_pool_config_add_option (config,
        GST_BUFFER_POOL_OPTION_VIDEO_META);
  }
  if (options & GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_ALIGNMENT) {
    gst_buffer_pool_config_add_option (config,
        GST_BUFFER_POOL_OPTION_VIDEO_ALIGNMENT);
  }
#if (GST_VAAPI_USE_GLX || GST_VAAPI_USE_EGL)
  if (options & GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_GL_TEXTURE_UPLOAD) {
    gst_buffer_pool_config_add_option (config,
        GST_BUFFER_POOL_OPTION_VIDEO_GL_TEXTURE_UPLOAD_META);
  }
#endif
  if (allocator)
    gst_buffer_pool_config_set_allocator (config, allocator, NULL);
  if (!gst_buffer_pool_set_config (pool, config)) {
    config = gst_buffer_pool_get_config (pool);

    if (!gst_buffer_pool_config_validate_params (config, caps, size,
            min_buffers, max_buffers)) {
      gst_structure_free (config);
      goto error_pool_config;
    }

    if (!gst_buffer_pool_set_config (pool, config))
      goto error_pool_config;
  }
  return pool;

  /* ERRORS */
error_create_pool:
  {
    GST_ERROR_OBJECT (plugin, "failed to create buffer pool");
    return NULL;
  }
error_pool_config:
  {
    gst_object_unref (pool);
    GST_ELEMENT_ERROR (plugin, RESOURCE, SETTINGS,
        ("Failed to configure the buffer pool"),
        ("Configuration is most likely invalid, please report this issue."));
    return NULL;
  }
}

/**
 * ensure_sinkpad_buffer_pool:
 * @plugin: a #GstVaapiPluginBase
 * @sinkpad: the #GstPad to use for the resulting buffer pool
 *
 * Makes sure the sink pad video buffer pool is created with the
 * appropriate caps defined in the @sinkpad.
 *
 * Returns: %TRUE if successful, %FALSE otherwise.
 */
static gboolean
ensure_sinkpad_buffer_pool (GstVaapiPluginBase * plugin, GstPad * sinkpad)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstCaps *caps = sinkpriv->caps;
  GstBufferPool *pool;
  guint size;

  /* video decoders don't use a buffer pool in the sink pad */
  if (GST_IS_VIDEO_DECODER (plugin))
    return TRUE;

  if (!gst_vaapi_plugin_base_ensure_display (plugin))
    return FALSE;

  if (sinkpriv->buffer_pool) {
    if (gst_vaapi_buffer_pool_caps_is_equal (sinkpriv->buffer_pool, caps))
      return TRUE;
    gst_buffer_pool_set_active (sinkpriv->buffer_pool, FALSE);
    gst_clear_object (&sinkpriv->buffer_pool);
    gst_clear_object (&sinkpriv->allocator);
    sinkpriv->buffer_size = 0;
  }

  if (!ensure_sinkpad_allocator (plugin, sinkpad, caps, &size))
    return FALSE;

  pool =
      gst_vaapi_plugin_base_create_pool (plugin, caps, size,
      BUFFER_POOL_SINK_MIN_BUFFERS, 0,
      GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META, sinkpriv->allocator);
  if (!pool)
    return FALSE;

  sinkpriv->buffer_pool = pool;
  sinkpriv->buffer_size = size;
  return TRUE;
}

static gboolean
_set_srcpad_caps (GstVaapiPluginBase * plugin, GstPad * srcpad, GstCaps * caps)
{
  GstVaapiPadPrivate *srcpriv = NULL;

  if (caps) {
    g_assert (srcpad);
    srcpriv = GST_VAAPI_PAD_PRIVATE (srcpad);
    g_assert (srcpriv);

    if (caps != srcpriv->caps) {
      if (!gst_video_info_from_caps (&srcpriv->info, caps))
        return FALSE;
      if (srcpriv->buffer_pool
          && !gst_vaapi_buffer_pool_caps_is_equal (srcpriv->buffer_pool,
              caps)) {
        gst_buffer_pool_set_active (srcpriv->buffer_pool, FALSE);
        gst_clear_object (&srcpriv->buffer_pool);
        gst_clear_object (&srcpriv->allocator);
        plugin_reset_texture_map (plugin);
      }
      gst_caps_replace (&srcpriv->caps, caps);
    }
  }

  return TRUE;
}

static gboolean
_set_sinkpad_caps (GstVaapiPluginBase * plugin, GstPad * sinkpad,
    GstCaps * caps)
{
  GstVaapiPadPrivate *sinkpriv = NULL;

  if (caps) {
    g_assert (sinkpad);
    sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
    g_assert (sinkpriv);

    if (caps != sinkpriv->caps) {
      if (!gst_video_info_from_caps (&sinkpriv->info, caps))
        return FALSE;
      gst_caps_replace (&sinkpriv->caps, caps);
      sinkpriv->caps_is_raw = !gst_caps_has_vaapi_surface (caps);
    }

    if (!ensure_sinkpad_buffer_pool (plugin, sinkpad))
      return FALSE;
  }

  return TRUE;
}

/**
 * gst_vaapi_plugin_base_pad_set_caps:
 * @plugin: a #GstVaapiPluginBase
 * @sinkpad: the sink pad to set @incaps on
 * @incaps: the sink pad (input) caps
 * @srcpad: the src pad to set @outcaps on
 * @outcaps: the src pad (output) caps
 *
 * Notifies the base plugin object of the new input and output caps,
 * obtained from the subclass on the requested pads.
 *
 * Returns: %TRUE if the update of caps was successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_pad_set_caps (GstVaapiPluginBase * plugin,
    GstPad * sinkpad, GstCaps * incaps, GstPad * srcpad, GstCaps * outcaps)
{
  return _set_sinkpad_caps (plugin, sinkpad, incaps)
      && _set_srcpad_caps (plugin, srcpad, outcaps);
}

/**
 * gst_vaapi_plugin_base_set_caps:
 * @plugin: a #GstVaapiPluginBase
 * @incaps: the sink pad (input) caps
 * @outcaps: the src pad (output) caps
 *
 * Notifies the base plugin object of the new input and output caps,
 * obtained from the subclass, on the base plugin static pads.
 *
 * Returns: %TRUE if the update of caps was successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_set_caps (GstVaapiPluginBase * plugin, GstCaps * incaps,
    GstCaps * outcaps)
{
  return gst_vaapi_plugin_base_pad_set_caps (plugin, plugin->sinkpad, incaps,
      plugin->srcpad, outcaps);
}

/**
 * gst_vaapi_plugin_base_pad_propose_allocation:
 * @plugin: a #GstVaapiPluginBase
 * @sinkpad: the sinkpad to configure the allocation query on
 * @query: the allocation query to configure
 *
 * Proposes allocation parameters to the upstream elements on the requested
 * sinkpad.
 *
 * Returns: %TRUE if successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_pad_propose_allocation (GstVaapiPluginBase * plugin,
    GstPad * sinkpad, GstQuery * query)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstCaps *caps = NULL;
  GstBufferPool *pool = NULL;
  gboolean need_pool;
  guint size = 0, n_allocators;

  gst_query_parse_allocation (query, &caps, &need_pool);
  if (!caps)
    goto error_no_caps;

  if (!ensure_sinkpad_allocator (plugin, sinkpad, caps, &size))
    return FALSE;

  if (need_pool) {
    pool = gst_vaapi_plugin_base_create_pool (plugin, caps, size,
        BUFFER_POOL_SINK_MIN_BUFFERS, 0,
        GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META, sinkpriv->allocator);
    if (!pool)
      return FALSE;
  }

  /* Set sinkpad allocator as the last allocation param.
   *
   * If there's none, set system's allocator first and VAAPI allocator
   * second
   */
  n_allocators = gst_query_get_n_allocation_params (query);
  if (n_allocators == 0) {
    GstAllocator *allocator;

    allocator = gst_allocator_find (GST_ALLOCATOR_SYSMEM);
    gst_query_add_allocation_param (query, allocator, NULL);
    gst_object_unref (allocator);
  }
  gst_query_add_allocation_param (query, sinkpriv->allocator, NULL);

  gst_query_add_allocation_pool (query, pool, size,
      BUFFER_POOL_SINK_MIN_BUFFERS, 0);
  if (pool)
    gst_object_unref (pool);

  gst_query_add_allocation_meta (query, GST_VAAPI_VIDEO_META_API_TYPE, NULL);
  gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
  return TRUE;

  /* ERRORS */
error_no_caps:
  {
    GST_INFO_OBJECT (plugin, "no caps specified");
    return FALSE;
  }
}

/**
 * gst_vaapi_plugin_base_propose_allocation:
 * @plugin: a #GstVaapiPluginBase
 * @query: the allocation query to configure
 *
 * Proposes allocation parameters to the upstream elements on the base plugin
 * static sinkpad.
 *
 * Returns: %TRUE if successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_propose_allocation (GstVaapiPluginBase * plugin,
    GstQuery * query)
{
  return gst_vaapi_plugin_base_pad_propose_allocation (plugin, plugin->sinkpad,
      query);
}

/**
 * gst_vaapi_plugin_base_decide_allocation:
 * @plugin: a #GstVaapiPluginBase
 * @query: the allocation query to parse
 * @feature: the desired #GstVaapiCapsFeature, or zero to find the
 *   preferred one
 *
 * Decides allocation parameters for the downstream elements on the base
 * plugin static srcpad.
 *
 * Returns: %TRUE if successful, %FALSE otherwise.
 */
gboolean
gst_vaapi_plugin_base_decide_allocation (GstVaapiPluginBase * plugin,
    GstQuery * query)
{
  GstVaapiPadPrivate *srcpriv = GST_VAAPI_PAD_PRIVATE (plugin->srcpad);
  GstCaps *caps = NULL;
  GstBufferPool *pool;
  GstVideoInfo vi;
  guint i, size, min, max, pool_options, num_allocators;
  gint index_allocator;
  gboolean update_pool = FALSE;
#if (GST_VAAPI_USE_GLX || GST_VAAPI_USE_EGL)
  guint idx;
#endif

  gst_query_parse_allocation (query, &caps, NULL);
  if (!caps)
    goto error_no_caps;

  pool_options = 0;
  if (gst_query_find_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL))
    pool_options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META;

#if (GST_VAAPI_USE_GLX || GST_VAAPI_USE_EGL)
  if (gst_query_find_allocation_meta (query,
          GST_VIDEO_GL_TEXTURE_UPLOAD_META_API_TYPE, &idx) &&
      gst_vaapi_caps_feature_contains (caps,
          GST_VAAPI_CAPS_FEATURE_GL_TEXTURE_UPLOAD_META))
    pool_options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_GL_TEXTURE_UPLOAD;

#if USE_GST_GL_HELPERS
  if (!plugin->gl_context &&
      (pool_options & GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_GL_TEXTURE_UPLOAD)) {
    const GstStructure *params;
    GstObject *gl_context;

    gst_query_parse_nth_allocation_meta (query, idx, &params);
    if (params) {
      if (gst_structure_get (params, "gst.gl.GstGLContext", GST_TYPE_GL_CONTEXT,
              &gl_context, NULL) && gl_context) {
        gst_vaapi_plugin_base_set_gl_context (plugin, gl_context);
        gst_vaapi_plugin_base_set_srcpad_can_dmabuf (plugin, gl_context);
        gst_object_unref (gl_context);
      }
    }
  }
#endif
#endif

  /* Make sure the display we pass down to the buffer pool is actually
     the expected one, especially when the downstream element requires
     a GLX or EGL display */
  if (!gst_vaapi_plugin_base_ensure_display (plugin))
    goto error_ensure_display;

  if (!gst_video_info_from_caps (&vi, caps))
    goto error_invalid_caps;
  gst_video_info_force_nv12_if_encoded (&vi);

  index_allocator = -1;
  num_allocators = gst_query_get_n_allocation_params (query);
  for (i = 0; i < num_allocators; i++) {
    GstAllocator *allocator = NULL;
    GstAllocationParams params;

    gst_query_parse_nth_allocation_param (query, i, &allocator, &params);
    if (!allocator)
      continue;

    /* Let's keep the the first allocator if it is not VA-API. It
     * might be used if it is required to copy the output frame to a
     * new buffer */
    if (i == 0
        && g_strcmp0 (allocator->mem_type, GST_VAAPI_VIDEO_MEMORY_NAME) != 0) {
      if (srcpriv->other_allocator)
        gst_object_unref (srcpriv->other_allocator);
      srcpriv->other_allocator = allocator;
      srcpriv->other_allocator_params = params;
      continue;
    }

    if (g_strcmp0 (allocator->mem_type, GST_VAAPI_VIDEO_MEMORY_NAME) == 0) {
      GST_DEBUG_OBJECT (plugin, "found vaapi allocator in query %"
          GST_PTR_FORMAT, allocator);
      index_allocator = i;
      if (srcpriv->allocator)
        gst_object_unref (srcpriv->allocator);
      srcpriv->allocator = allocator;
      break;
    }
    gst_object_unref (allocator);
  }

  if (gst_query_get_n_allocation_pools (query) > 0) {
    gst_query_parse_nth_allocation_pool (query, 0, &pool, &size, &min, &max);
    update_pool = TRUE;
    size = MAX (size, GST_VIDEO_INFO_SIZE (&vi));
    if (pool) {
      /* Check whether downstream element proposed a bufferpool but did
         not provide a correct propose_allocation() implementation */
      if (gst_buffer_pool_has_option (pool,
              GST_BUFFER_POOL_OPTION_VIDEO_ALIGNMENT))
        pool_options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_ALIGNMENT;

      /* GstVaapiVideoMeta is mandatory, and this implies VA surface memory */
      if (!gst_buffer_pool_has_option (pool,
              GST_BUFFER_POOL_OPTION_VAAPI_VIDEO_META)) {
        GST_INFO_OBJECT (plugin, "ignoring non-VAAPI pool: %" GST_PTR_FORMAT,
            pool);
        gst_clear_object (&pool);
      }
    }
  } else {
    pool = NULL;
    size = GST_VIDEO_INFO_SIZE (&vi);
    min = max = 0;
  }

  if (!pool) {
    if (!ensure_srcpad_allocator (plugin, plugin->srcpad, &vi, caps))
      goto error;
    size = GST_VIDEO_INFO_SIZE (&vi);   /* size might be updated by
                                         * allocator */
    pool = gst_vaapi_plugin_base_create_pool (plugin, caps, size, min, max,
        pool_options, srcpriv->allocator);
    if (!pool)
      goto error;
  }

  if (update_pool)
    gst_query_set_nth_allocation_pool (query, 0, pool, size, min, max);
  else
    gst_query_add_allocation_pool (query, pool, size, min, max);

  /* allocator might be updated by ensure_srcpad_allocator() */
  if (srcpriv->allocator) {
    if (index_allocator > 0) {
      gst_query_set_nth_allocation_param (query, index_allocator,
          srcpriv->allocator, NULL);
    } else {
      GST_DEBUG_OBJECT (plugin, "adding allocator in query %" GST_PTR_FORMAT,
          srcpriv->allocator);
      gst_query_add_allocation_param (query, srcpriv->allocator, NULL);
    }
  }

  gst_clear_object (&srcpriv->buffer_pool);
  srcpriv->buffer_pool = pool;

  /* if downstream doesn't support GstVideoMeta, and the negotiated
   * caps are raw video, and the used allocator is the VA-API one, we
   * should copy the VA-API frame into a dumb buffer */
  plugin->copy_output_frame = gst_vaapi_video_buffer_pool_copy_buffer (pool);

  return TRUE;

  /* ERRORS */
error_no_caps:
  {
    GST_ERROR_OBJECT (plugin, "no caps specified");
    return FALSE;
  }
error_invalid_caps:
  {
    GST_ERROR_OBJECT (plugin, "invalid caps %" GST_PTR_FORMAT, caps);
    return FALSE;
  }
error_ensure_display:
  {
    GST_ERROR_OBJECT (plugin, "failed to ensure display of type %d",
        plugin->display_type_req);
    return FALSE;
  }
error:
  {
    /* error message already sent */
    return FALSE;
  }
}

/**
 * gst_vaapi_plugin_base_pad_get_input_buffer:
 * @plugin: a #GstVaapiPluginBase
 * @sinkpad: the sink pad to obtain input buffer on
 * @inbuf: the sink pad (input) buffer
 * @outbuf_ptr: the pointer to location to the VA surface backed buffer
 *
 * Acquires the static sink pad (input) buffer as a VA surface backed
 * buffer. This is mostly useful for raw YUV buffers, as source
 * buffers that are already backed as a VA surface are passed
 * verbatim.
 *
 * Returns: #GST_FLOW_OK if the buffer could be acquired
 */
GstFlowReturn
gst_vaapi_plugin_base_pad_get_input_buffer (GstVaapiPluginBase * plugin,
    GstPad * sinkpad, GstBuffer * inbuf, GstBuffer ** outbuf_ptr)
{
  GstVaapiPadPrivate *sinkpriv = GST_VAAPI_PAD_PRIVATE (sinkpad);
  GstVaapiVideoMeta *meta;
  GstBuffer *outbuf;
  GstVideoFrame src_frame, out_frame;
  gboolean success;

  g_return_val_if_fail (inbuf != NULL, GST_FLOW_ERROR);
  g_return_val_if_fail (outbuf_ptr != NULL, GST_FLOW_ERROR);

  meta = gst_buffer_get_vaapi_video_meta (inbuf);
  if (meta) {
    *outbuf_ptr = gst_buffer_ref (inbuf);
    return GST_FLOW_OK;
  }

  if (!sinkpriv->caps_is_raw)
    goto error_invalid_buffer;

  if (!sinkpriv->buffer_pool)
    goto error_no_pool;

  if (!gst_buffer_pool_is_active (sinkpriv->buffer_pool) &&
      !gst_buffer_pool_set_active (sinkpriv->buffer_pool, TRUE))
    goto error_active_pool;

  outbuf = NULL;
  if (gst_buffer_pool_acquire_buffer (sinkpriv->buffer_pool,
          &outbuf, NULL) != GST_FLOW_OK)
    goto error_create_buffer;

  if (is_dma_buffer (inbuf)) {
    if (!plugin_bind_dma_to_vaapi_buffer (plugin, sinkpad, inbuf, outbuf))
      goto error_bind_dma_buffer;
    goto done;
  }

  if (!gst_video_frame_map (&src_frame, &sinkpriv->info, inbuf, GST_MAP_READ))
    goto error_map_src_buffer;

  if (!gst_video_frame_map (&out_frame, &sinkpriv->info, outbuf, GST_MAP_WRITE))
    goto error_map_dst_buffer;

  success = gst_video_frame_copy (&out_frame, &src_frame);
  gst_video_frame_unmap (&out_frame);
  gst_video_frame_unmap (&src_frame);
  if (!success)
    goto error_copy_buffer;

done:
  if (!gst_buffer_copy_into (outbuf, inbuf, GST_BUFFER_COPY_FLAGS |
          GST_BUFFER_COPY_TIMESTAMPS | GST_BUFFER_COPY_META, 0, -1))
    return GST_FLOW_ERROR;
  *outbuf_ptr = outbuf;
  return GST_FLOW_OK;

  /* ERRORS */
error_no_pool:
  {
    GST_ELEMENT_ERROR (plugin, STREAM, FAILED,
        ("no buffer pool was negotiated"), ("no buffer pool was negotiated"));
    return GST_FLOW_ERROR;
  }
error_active_pool:
  {
    GST_ELEMENT_ERROR (plugin, STREAM, FAILED,
        ("failed to activate buffer pool"), ("failed to activate buffer pool"));
    return GST_FLOW_ERROR;
  }
error_map_dst_buffer:
  {
    gst_video_frame_unmap (&src_frame);
    // fall-through
  }
error_map_src_buffer:
  {
    GST_WARNING ("failed to map buffer");
    gst_buffer_unref (outbuf);
    return GST_FLOW_NOT_SUPPORTED;
  }

  /* ERRORS */
error_invalid_buffer:
  {
    GST_ELEMENT_ERROR (plugin, STREAM, FAILED,
        ("failed to validate source buffer"),
        ("failed to validate source buffer"));
    return GST_FLOW_ERROR;
  }
error_create_buffer:
  {
    GST_ELEMENT_ERROR (plugin, STREAM, FAILED, ("Allocation failed"),
        ("failed to create buffer"));
    return GST_FLOW_ERROR;
  }
error_bind_dma_buffer:
  {
    GST_ELEMENT_ERROR (plugin, STREAM, FAILED, ("Allocation failed"),
        ("failed to bind dma_buf to VA surface buffer"));
    gst_buffer_unref (outbuf);
    return GST_FLOW_ERROR;
  }
error_copy_buffer:
  {
    GST_WARNING_OBJECT (plugin, "failed to upload buffer to VA surface");
    gst_buffer_unref (outbuf);
    return GST_FLOW_NOT_SUPPORTED;
  }
}

/**
 * gst_vaapi_plugin_base_get_input_buffer:
 * @plugin: a #GstVaapiPluginBase
 * @inbuf: the sink pad (input) buffer
 * @outbuf_ptr: the pointer to location to the VA surface backed buffer
 *
 * Acquires the static sink pad (input) buffer as a VA surface backed
 * buffer. This is mostly useful for raw YUV buffers, as source
 * buffers that are already backed as a VA surface are passed
 * verbatim.
 *
 * Returns: #GST_FLOW_OK if the buffer could be acquired
 */
GstFlowReturn
gst_vaapi_plugin_base_get_input_buffer (GstVaapiPluginBase * plugin,
    GstBuffer * inbuf, GstBuffer ** outbuf_ptr)
{
  return gst_vaapi_plugin_base_pad_get_input_buffer (plugin, plugin->sinkpad,
      inbuf, outbuf_ptr);
}

/**
 * gst_vaapi_plugin_base_set_gl_context:
 * @plugin: a #GstVaapiPluginBase
 * @object: the new GL context from downstream
 *
 * Registers the new GL context. The change is effective at the next
 * call to gst_vaapi_plugin_base_ensure_display(), where the
 * underlying display object could be re-allocated to fit the GL
 * context needs
 */
void
gst_vaapi_plugin_base_set_gl_context (GstVaapiPluginBase * plugin,
    GstObject * object)
{
#if USE_GST_GL_HELPERS
  GstGLContext *const gl_context = GST_GL_CONTEXT (object);
  GstVaapiDisplayType display_type;

  if (plugin->gl_context == object)
    return;

  gst_object_replace (&plugin->gl_context, object);

  switch (gst_gl_context_get_gl_platform (gl_context)) {
#if GST_VAAPI_USE_GLX
    case GST_GL_PLATFORM_GLX:
      display_type = GST_VAAPI_DISPLAY_TYPE_GLX;
      break;
#endif
    case GST_GL_PLATFORM_EGL:
#if GST_VAAPI_USE_EGL
      display_type = GST_VAAPI_DISPLAY_TYPE_EGL;
      break;
#endif
    default:
      display_type = plugin->display_type;
      break;
  }
  GST_INFO_OBJECT (plugin, "GL context: %" GST_PTR_FORMAT, plugin->gl_context);
  gst_vaapi_plugin_base_set_display_type (plugin, display_type);
#endif
}

/**
 * gst_vaapi_plugin_base_create_gl_context:
 * @plugin: a #GstVaapiPluginBase
 *
 * It queries downstream and upstream for a #GstGLDisplay and a other
 * #GstGLContext. If not found, a new #GstGLDisplay and #GstGLContext
 * are created, if it is possible.
 *
 * Returns: (transfer full) a new created #GstGLContext or %NULL
 **/
GstObject *
gst_vaapi_plugin_base_create_gl_context (GstVaapiPluginBase * plugin)
{
#if USE_GST_GL_HELPERS
  GstGLContext *gl_other_context = NULL, *gl_context = NULL;
  GstGLDisplay *gl_display = NULL;

  if (!plugin->gl_display)
    return NULL;

  gl_display = (GstGLDisplay *) plugin->gl_display;
  if (gst_gl_display_get_handle_type (gl_display) == GST_GL_DISPLAY_TYPE_ANY)
    goto no_valid_gl_display;
  gl_other_context = (GstGLContext *) plugin->gl_other_context;

  GST_INFO_OBJECT (plugin, "creating a new GstGL context");

  GST_OBJECT_LOCK (gl_display);
  do {
    if (gl_context)
      gst_object_unref (gl_context);
    gl_context = gst_gl_display_get_gl_context_for_thread (gl_display, NULL);
    if (!gl_context) {
      if (!gst_gl_display_create_context (gl_display, gl_other_context,
              &gl_context, NULL))
        break;
    }
  } while (!gst_gl_display_add_context (gl_display, gl_context));
  GST_OBJECT_UNLOCK (gl_display);

  return GST_OBJECT_CAST (gl_context);

  /* ERRORS */
no_valid_gl_display:
  {
    GST_INFO_OBJECT (plugin, "No valid GL display found");
    gst_object_replace (&plugin->gl_display, NULL);
    gst_object_replace (&plugin->gl_other_context, NULL);
    return NULL;
  }
#else
  return NULL;
#endif
}

static GArray *
extract_allowed_surface_formats (GstVaapiDisplay * display,
    GArray * img_formats)
{
  guint i;
  GArray *out_formats;
  guint surface_chroma = 0;
  GstVaapiSurface *surface = NULL;

  /* let's assume all the formats are possible to download */
  if (gst_vaapi_display_has_driver_quirks (display,
          GST_VAAPI_DRIVER_QUIRK_NO_CHECK_SURFACE_PUT_IMAGE)) {
    out_formats = g_array_ref (img_formats);
    goto bail;
  }

  out_formats =
      g_array_sized_new (FALSE, FALSE, sizeof (GstVideoFormat),
      img_formats->len);
  if (!out_formats)
    return NULL;

  for (i = 0; i < img_formats->len; i++) {
    const GstVideoFormat img_format =
        g_array_index (img_formats, GstVideoFormat, i);
    GstVaapiImage *image;
    GstVideoInfo vi;
    guint img_chroma;

    if (img_format == GST_VIDEO_FORMAT_UNKNOWN)
      continue;

    img_chroma = gst_vaapi_video_format_get_chroma_type (img_format);
    if (img_chroma != surface_chroma) {
      if (surface)
        gst_vaapi_surface_unref (surface);
      gst_video_info_set_format (&vi, img_format, 64, 64);
      surface = gst_vaapi_surface_new_full (display, &vi, 0);
      if (!surface)
        continue;
      surface_chroma = img_chroma;
    }

    image = gst_vaapi_image_new (display, img_format, 64, 64);
    if (!image)
      continue;
    if (gst_vaapi_surface_put_image (surface, image))
      g_array_append_val (out_formats, img_format);
    gst_vaapi_image_unref (image);
  }

  if (surface)
    gst_vaapi_surface_unref (surface);

bail:
  if (out_formats->len == 0) {
    g_array_unref (out_formats);
    return NULL;
  }
  return out_formats;
}

static gboolean
ensure_allowed_raw_caps (GstVaapiPluginBase * plugin)
{
  GArray *formats, *out_formats;
  GstVaapiDisplay *display;
  GstCaps *out_caps;
  gboolean ret = FALSE;

  if (plugin->allowed_raw_caps)
    return TRUE;

  out_formats = NULL;
  display = gst_object_ref (plugin->display);
  formats = gst_vaapi_display_get_image_formats (display);
  if (!formats)
    goto bail;
  out_formats = extract_allowed_surface_formats (display, formats);
  if (!out_formats)
    goto bail;
  out_caps = gst_vaapi_video_format_new_template_caps_from_list (out_formats);
  if (!out_caps)
    goto bail;

  gst_caps_replace (&plugin->allowed_raw_caps, out_caps);
  gst_caps_unref (out_caps);
  ret = TRUE;

bail:
  if (formats)
    g_array_unref (formats);
  if (out_formats)
    g_array_unref (out_formats);
  gst_object_unref (display);

  return ret;
}

/**
 * gst_vaapi_plugin_base_get_allowed_sinkpad_raw_caps:
 * @plugin: a #GstVaapiPluginBase
 *
 * Returns the raw #GstCaps allowed by the element.
 *
 * Returns: the allowed raw #GstCaps or %NULL
 **/
GstCaps *
gst_vaapi_plugin_base_get_allowed_sinkpad_raw_caps (GstVaapiPluginBase * plugin)
{
  if (!ensure_allowed_raw_caps (plugin))
    return NULL;
  return plugin->allowed_raw_caps;
}

/**
 * gst_vaapi_plugin_base_set_srcpad_can_dmabuf:
 * @plugin: a #GstVaapiPluginBase
 * @object: the GL context from gst-gl
 *
 * This function will determine if @object supports dmabuf
 * importing on the base plugin static srcpad.
 *
 * Please note that the context @object should come from downstream.
 **/
void
gst_vaapi_plugin_base_set_srcpad_can_dmabuf (GstVaapiPluginBase * plugin,
    GstObject * object)
{
#if GST_VAAPI_USE_EGL && USE_GST_GL_HELPERS
  GstVaapiPadPrivate *srcpriv = GST_VAAPI_PAD_PRIVATE (plugin->srcpad);
  GstGLContext *const gl_context = GST_GL_CONTEXT (object);

  srcpriv->can_dmabuf =
      (!(gst_gl_context_get_gl_api (gl_context) & GST_GL_API_GLES1)
      && gst_gl_context_check_feature (gl_context,
          "EGL_EXT_image_dma_buf_import"));
#endif
}

static void
_init_performance_debug (void)
{
#ifndef GST_DISABLE_GST_DEBUG
  static gsize _init = 0;

  if (g_once_init_enter (&_init)) {
    GST_DEBUG_CATEGORY_GET (CAT_PERFORMANCE, "GST_PERFORMANCE");
    g_once_init_leave (&_init, 1);
  }
#endif
}

/**
 * gst_vaapi_plugin_copy_va_buffer:
 * @plugin: a #GstVaapiPluginBase
 * @inbuf: a #GstBuffer with VA memory type
 * @outbuf: a #GstBuffer with system allocated memory
 *
 * Copy @inbuf to @outbuf. This if required when downstream doesn't
 * support GstVideoMeta, and since VA memory may have custom strides a
 * frame copy is required.
 *
 * Returns: %FALSE if the copy failed, otherwise %TRUE. Also returns
 *          %TRUE if it is not required to do the copy
 **/
gboolean
gst_vaapi_plugin_copy_va_buffer (GstVaapiPluginBase * plugin,
    GstBuffer * inbuf, GstBuffer * outbuf)
{
  GstVaapiPadPrivate *srcpriv = GST_VAAPI_PAD_PRIVATE (plugin->srcpad);
  GstVideoMeta *vmeta;
  GstVideoFrame src_frame, dst_frame;
  gboolean success;

  if (!plugin->copy_output_frame)
    return TRUE;

  /* inbuf shall have video meta */
  vmeta = gst_buffer_get_video_meta (inbuf);
  if (!vmeta)
    return FALSE;

  _init_performance_debug ();
  GST_CAT_INFO (CAT_PERFORMANCE, "copying VA buffer to system memory buffer");

  if (!gst_video_frame_map (&src_frame, &srcpriv->info, inbuf, GST_MAP_READ))
    return FALSE;
  if (!gst_video_frame_map (&dst_frame, &srcpriv->info, outbuf, GST_MAP_WRITE)) {
    gst_video_frame_unmap (&src_frame);
    return FALSE;
  }
  success = gst_video_frame_copy (&dst_frame, &src_frame);
  gst_video_frame_unmap (&dst_frame);
  gst_video_frame_unmap (&src_frame);

  if (success) {
    gst_buffer_copy_into (outbuf, inbuf, GST_BUFFER_COPY_TIMESTAMPS
        | GST_BUFFER_COPY_FLAGS, 0, -1);
  }

  return success;
}