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
gst_vaapi_video_buffer_pool_set_config (GstBufferPool * pool,
    GstStructure * config)
{
  GstVaapiVideoBufferPoolPrivate *const priv =
      GST_VAAPI_VIDEO_BUFFER_POOL (pool)->priv;
  GstCaps *caps;
  GstVideoInfo new_allocation_vinfo;
  const GstVideoInfo *allocator_vinfo;
  const GstVideoInfo *negotiated_vinfo;
  GstVideoAlignment align;
  GstAllocator *allocator;
  gboolean ret, updated = FALSE;
  guint size, min_buffers, max_buffers;
  guint surface_alloc_flags;

  GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);

  caps = NULL;
  if (!gst_buffer_pool_config_get_params (config, &caps, &size, &min_buffers,
          &max_buffers))
    goto error_invalid_config;
  if (!caps)
    goto error_no_caps;
  if (!gst_video_info_from_caps (&new_allocation_vinfo, caps))
    goto error_invalid_caps;

  allocator = NULL;
  if (!gst_buffer_pool_config_get_allocator (config, &allocator, NULL))
    goto error_invalid_allocator;

  /* it is a valid allocator? */
  if (allocator
      && (g_strcmp0 (allocator->mem_type, GST_VAAPI_VIDEO_MEMORY_NAME) != 0
          && g_strcmp0 (allocator->mem_type,
              GST_VAAPI_DMABUF_ALLOCATOR_NAME) != 0))
    allocator = NULL;

  /* get the allocator properties */
  if (allocator) {
    priv->use_dmabuf_memory = gst_vaapi_is_dmabuf_allocator (allocator);
    negotiated_vinfo =
        gst_allocator_get_vaapi_negotiated_video_info (allocator);
    allocator_vinfo =
        gst_allocator_get_vaapi_video_info (allocator, &surface_alloc_flags);
  } else {
    priv->use_dmabuf_memory = FALSE;
    negotiated_vinfo = NULL;
    allocator_vinfo = NULL;
    surface_alloc_flags = 0;
  }

  /* reset or update the allocator if video resolution changed */
  if (allocator_vinfo
      && gst_video_info_changed (allocator_vinfo, &new_allocation_vinfo)) {
    gst_object_replace ((GstObject **) & priv->allocator, NULL);

    if (allocator && priv->use_dmabuf_memory) {
      gst_allocator_set_vaapi_video_info (allocator, &new_allocation_vinfo,
          surface_alloc_flags);
    } else {
      allocator = NULL;
    }
  }

  if (!gst_buffer_pool_config_has_option (config,
          GST_BUFFER_POOL_OPTION_VAAPI_VIDEO_META))
    goto error_no_vaapi_video_meta_option;

  /* create a new allocator if needed */
  if (!allocator) {
    if (priv->use_dmabuf_memory) {
      allocator = gst_vaapi_dmabuf_allocator_new (priv->display,
          &new_allocation_vinfo, /* FIXME: */ 0, GST_PAD_SRC);
    } else {
      allocator = gst_vaapi_video_allocator_new (priv->display,
          &new_allocation_vinfo, surface_alloc_flags, 0);
    }

    if (!allocator)
      goto error_no_allocator;

    if (negotiated_vinfo) {
      gst_allocator_set_vaapi_negotiated_video_info (allocator,
          negotiated_vinfo);
    }

    GST_INFO_OBJECT (pool, "created new allocator %" GST_PTR_FORMAT, allocator);
    gst_buffer_pool_config_set_allocator (config, allocator, NULL);
    gst_object_unref (allocator);
  }

  /* use the allocator and set the video info for the vmeta */
  if (allocator) {
    if (priv->allocator)
      gst_object_unref (priv->allocator);
    if ((priv->allocator = allocator))
      gst_object_ref (allocator);

    negotiated_vinfo =
        gst_allocator_get_vaapi_negotiated_video_info (priv->allocator);
    allocator_vinfo = gst_allocator_get_vaapi_video_info (allocator, NULL);
    priv->vmeta_vinfo = (negotiated_vinfo) ?
        *negotiated_vinfo : *allocator_vinfo;

    /* last resource to set the correct buffer size */
    if (GST_VIDEO_INFO_SIZE (allocator_vinfo) != size) {
      gst_buffer_pool_config_set_params (config, caps,
          GST_VIDEO_INFO_SIZE (allocator_vinfo), min_buffers, max_buffers);
    }
  }
  if (!priv->allocator)
    goto error_no_allocator;

  priv->options = 0;
  if (gst_buffer_pool_config_has_option (config,
          GST_BUFFER_POOL_OPTION_VIDEO_META)) {
    priv->options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META;
  } else {
    gint i;
    for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&new_allocation_vinfo); i++) {
      if (GST_VIDEO_INFO_PLANE_OFFSET (&new_allocation_vinfo, i) !=
          GST_VIDEO_INFO_PLANE_OFFSET (&priv->vmeta_vinfo, i) ||
          GST_VIDEO_INFO_PLANE_STRIDE (&new_allocation_vinfo, i) !=
          GST_VIDEO_INFO_PLANE_STRIDE (&priv->vmeta_vinfo, i)) {
        priv->options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_VIDEO_META;
        gst_buffer_pool_config_add_option (config,
            GST_BUFFER_POOL_OPTION_VIDEO_META);
        updated = TRUE;
        break;
      }
    }
  }

  if (gst_buffer_pool_config_has_option (config,
          GST_BUFFER_POOL_OPTION_VIDEO_ALIGNMENT)) {
    fill_video_alignment (GST_VAAPI_VIDEO_BUFFER_POOL (pool), &align);
    gst_buffer_pool_config_set_video_alignment (config, &align);
  }

  if (!priv->use_dmabuf_memory && gst_buffer_pool_config_has_option (config,
          GST_BUFFER_POOL_OPTION_VIDEO_GL_TEXTURE_UPLOAD_META))
    priv->options |= GST_VAAPI_VIDEO_BUFFER_POOL_OPTION_GL_TEXTURE_UPLOAD;

  ret =
      GST_BUFFER_POOL_CLASS
      (gst_vaapi_video_buffer_pool_parent_class)->set_config (pool, config);
  return !updated && ret;

  /* ERRORS */
error_invalid_config:
  {
    GST_ERROR_OBJECT (pool, "invalid config");
    return FALSE;
  }
error_no_caps:
  {
    GST_ERROR_OBJECT (pool, "no caps in config");
    return FALSE;
  }
error_invalid_caps:
  {
    GST_ERROR_OBJECT (pool, "invalid caps %" GST_PTR_FORMAT, caps);
    return FALSE;
  }
error_invalid_allocator:
  {
    GST_ERROR_OBJECT (pool, "no allocator in config");
    return FALSE;
  }
error_no_vaapi_video_meta_option:
  {
    GST_ERROR_OBJECT (pool, "no GstVaapiVideoMeta option in config");
    return FALSE;
  }
error_no_allocator:
  {
    GST_ERROR_OBJECT (pool, "no allocator defined");
    return FALSE;
  }
}