/* GStreamer
 * Copyright (C) 2017 Ericsson AB. All rights reserved.
 * Copyright (C) 2019 Seungha Yang <seungha.yang@navercorp.com>
 * Copyright (C) 2020 Seungha Yang <seungha@centricular.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * 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.
 *
 * Copyright 2015 The Chromium Authors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *    * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * SECTION:element-nvh265sldec
 * @title: nvh265sldec
 *
 * GstCodecs based NVIDIA H.265 video decoder
 *
 * ## Example launch line
 * ```
 * gst-launch-1.0 filesrc location=/path/to/h265/file ! parsebin ! nvh265sldec ! videoconvert ! autovideosink
 * ```
 *
 * Since: 1.18
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gst/cuda/gstcudautils.h>
#include "gstnvh265dec.h"
#include "gstnvdecoder.h"

#include <string.h>

GST_DEBUG_CATEGORY_STATIC (gst_nv_h265_dec_debug);
#define GST_CAT_DEFAULT gst_nv_h265_dec_debug

#define DOC_SINK_CAPS \
    "video/x-h265, width = (int) [ 144, 8192 ], height = (int) [ 144, 8192 ], " \
    "stream-format= (string) { hev1, hvc1, byte-stream  }, " \
    "alignment= (string) au, " \
    "profile = (string) { main, main-10, main-12, main-444, main-444-10, main-444-12 }"

#define DOC_SRC_CAPS_COMM \
    "format = (string) { NV12, P010_10LE, P012_LE, Y444, Y444_16LE, GBR, GBR_16LE }, " \
    "width = (int) [ 144, 8192 ], height = (int) [ 144, 8192 ]"

#define DOC_SRC_CAPS_D3D11 \
    "format = (string) { I420, I420_10LE, I420_12LE, Y444, Y444_16LE, GBR, GBR_16LE }, " \
    "width = (int) [ 144, 8192 ], height = (int) [ 144, 8192 ]"

#define DOC_SRC_CAPS_GL \
    "format = (string) { I420, I420_10LE, I420_12LE, Y444, Y444_16LE, GBR }, " \
    "width = (int) [ 144, 8192 ], height = (int) [ 144, 8192 ]"

#define DOC_SRC_CAPS \
    "video/x-raw(memory:CUDAMemory), " DOC_SRC_CAPS_COMM "; " \
    "video/x-raw(memory:D3D12Memory), " DOC_SRC_CAPS_COMM "; " \
    "video/x-raw(memory:D3D11Memory), " DOC_SRC_CAPS_D3D11 "; " \
    "video/x-raw(memory:GLMemory), " DOC_SRC_CAPS_GL "; " \
    "video/x-raw, " DOC_SRC_CAPS_COMM

typedef struct _GstNvH265Dec
{
  GstH265Decoder parent;

  GstNvDecoder *decoder;
  CUVIDPICPARAMS params;

  /* slice buffer which will be passed to CUVIDPICPARAMS::pBitstreamData */
  guint8 *bitstream_buffer;
  /* allocated memory size of bitstream_buffer */
  gsize bitstream_buffer_alloc_size;
  /* current offset of bitstream_buffer (per frame) */
  gsize bitstream_buffer_offset;

  guint *slice_offsets;
  guint slice_offsets_alloc_len;
  guint num_slices;

  guint width, height;
  guint coded_width, coded_height;
  guint bitdepth;
  guint chroma_format_idc;
  gint max_dpb_size;

  guint num_output_surfaces;
  guint init_max_width;
  guint init_max_height;
  gint max_display_delay;

  GstVideoFormat out_format;
} GstNvH265Dec;

typedef struct _GstNvH265DecClass
{
  GstH265DecoderClass parent_class;
  guint cuda_device_id;
  gint64 adapter_luid;
  guint max_width;
  guint max_height;
} GstNvH265DecClass;

enum
{
  PROP_0,
  PROP_CUDA_DEVICE_ID,
  PROP_NUM_OUTPUT_SURFACES,
  PROP_INIT_MAX_WIDTH,
  PROP_INIT_MAX_HEIGHT,
  PROP_MAX_DISPLAY_DELAY,
};

#define DEFAULT_NUM_OUTPUT_SURFACES 1
#define DEFAULT_MAX_DISPLAY_DELAY -1

static GTypeClass *parent_class = nullptr;

#define GST_NV_H265_DEC(object) ((GstNvH265Dec *) (object))
#define GST_NV_H265_DEC_GET_CLASS(object) \
    (G_TYPE_INSTANCE_GET_CLASS ((object),G_TYPE_FROM_INSTANCE (object),GstNvH265DecClass))

static void gst_nv_h265_dec_finalize (GObject * object);
static void gst_nv_h265_dec_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_nv_h265_dec_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

static void gst_nv_h265_dec_set_context (GstElement * element,
    GstContext * context);
static gboolean gst_nv_h265_dec_open (GstVideoDecoder * decoder);
static gboolean gst_nv_h265_dec_close (GstVideoDecoder * decoder);
static gboolean gst_nv_h265_dec_stop (GstVideoDecoder * decoder);
static gboolean gst_nv_h265_dec_negotiate (GstVideoDecoder * decoder);
static gboolean gst_nv_h265_dec_decide_allocation (GstVideoDecoder *
    decoder, GstQuery * query);
static gboolean gst_nv_h265_dec_sink_query (GstVideoDecoder * decoder,
    GstQuery * query);
static gboolean gst_nv_h265_dec_src_query (GstVideoDecoder * decoder,
    GstQuery * query);
static gboolean gst_nv_h265_dec_sink_event (GstVideoDecoder * decoder,
    GstEvent * event);

/* GstH265Decoder */
static GstFlowReturn gst_nv_h265_dec_new_sequence (GstH265Decoder * decoder,
    const GstH265SPS * sps, gint max_dpb_size);
static GstFlowReturn gst_nv_h265_dec_new_picture (GstH265Decoder * decoder,
    GstVideoCodecFrame * frame, GstH265Picture * picture);
static GstFlowReturn gst_nv_h265_dec_output_picture (GstH265Decoder *
    decoder, GstVideoCodecFrame * frame, GstH265Picture * picture);
static GstFlowReturn gst_nv_h265_dec_start_picture (GstH265Decoder * decoder,
    GstH265Picture * picture, GstH265Slice * slice, GstH265Dpb * dpb);
static GstFlowReturn gst_nv_h265_dec_decode_slice (GstH265Decoder * decoder,
    GstH265Picture * picture, GstH265Slice * slice,
    GArray * ref_pic_list0, GArray * ref_pic_list1);
static GstFlowReturn gst_nv_h265_dec_end_picture (GstH265Decoder * decoder,
    GstH265Picture * picture);
static guint
gst_nv_h265_dec_get_preferred_output_delay (GstH265Decoder * decoder,
    gboolean live);

static void
gst_nv_h265_dec_class_init (GstNvH265DecClass * klass,
    GstNvDecoderClassData * cdata)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
  GstVideoDecoderClass *decoder_class = GST_VIDEO_DECODER_CLASS (klass);
  GstH265DecoderClass *h265decoder_class = GST_H265_DECODER_CLASS (klass);

  object_class->finalize = gst_nv_h265_dec_finalize;
  object_class->set_property = gst_nv_h265_dec_set_property;
  object_class->get_property = gst_nv_h265_dec_get_property;

  /**
   * GstNvH265Dec:cuda-device-id:
   *
   * Assigned CUDA device id
   *
   * Since: 1.22
   */
  g_object_class_install_property (object_class, PROP_CUDA_DEVICE_ID,
      g_param_spec_uint ("cuda-device-id", "CUDA device id",
          "Assigned CUDA device id", 0, G_MAXINT, 0,
          (GParamFlags) (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS)));

  /**
   * GstNvH265Dec:num-output-surfaces:
   *
   * The number of output surfaces (0 = auto, 1 = always copy).
   * This property will be used to calculate
   * the CUVIDDECODECREATEINFO.ulNumOutputSurfaces parameter in case of
   * CUDA output mode.
   *
   * Since: 1.24
   */
  g_object_class_install_property (object_class, PROP_NUM_OUTPUT_SURFACES,
      g_param_spec_uint ("num-output-surfaces", "Num Output Surfaces",
          "Maximum number of output surfaces simultaneously mapped in CUDA "
          "output mode (0 = auto, 1 = always copy)",
          0, 64, DEFAULT_NUM_OUTPUT_SURFACES,
          (GParamFlags) (GST_PARAM_MUTABLE_READY | G_PARAM_READWRITE |
              G_PARAM_STATIC_STRINGS)));

  /**
   * GstNvH265Dec:init-max-width:
   *
   * Initial CUVIDDECODECREATEINFO.ulMaxWidth value
   *
   * Since: 1.24
   */
  g_object_class_install_property (object_class, PROP_INIT_MAX_WIDTH,
      g_param_spec_uint ("init-max-width", "Initial Maximum Width",
          "Expected maximum coded width of stream. This value is used to "
          "pre-allocate higher dimension of output surfaces than "
          "that of input stream, in order to help decoder reconfiguration",
          0, cdata->max_width, 0,
          (GParamFlags) (GST_PARAM_MUTABLE_READY | G_PARAM_READWRITE |
              G_PARAM_STATIC_STRINGS)));

  /**
   * GstNvH265Dec:init-max-height:
   *
   * Initial CUVIDDECODECREATEINFO.ulMaxHeight value
   *
   * Since: 1.24
   */
  g_object_class_install_property (object_class, PROP_INIT_MAX_HEIGHT,
      g_param_spec_uint ("init-max-height", "Initial Maximum Height",
          "Expected maximum coded height of stream. This value is used to "
          "pre-allocate higher dimension of output surfaces than "
          "that of input stream, in order to help decoder reconfiguration",
          0, cdata->max_height, 0,
          (GParamFlags) (GST_PARAM_MUTABLE_READY | G_PARAM_READWRITE |
              G_PARAM_STATIC_STRINGS)));

  /**
   * GstNvH265Dec:max-display-delay:
   *
   * Maximum display delay
   *
   * Since: 1.24
   */
  g_object_class_install_property (object_class, PROP_MAX_DISPLAY_DELAY,
      g_param_spec_int ("max-display-delay", "Max Display Delay",
          "Improves pipelining of decode with display, 0 means no delay "
          "(auto = -1)", -1, 16, DEFAULT_MAX_DISPLAY_DELAY,
          (GParamFlags) (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));

  element_class->set_context = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_set_context);

  parent_class = (GTypeClass *) g_type_class_peek_parent (klass);
  gst_element_class_set_static_metadata (element_class,
      "NVDEC H.265 Decoder",
      "Codec/Decoder/Video/Hardware",
      "NVIDIA H.265 video decoder", "Seungha Yang <seungha@centricular.com>");

  auto pad_templ = gst_pad_template_new ("sink",
      GST_PAD_SINK, GST_PAD_ALWAYS, cdata->sink_caps);
  auto doc_caps = gst_caps_from_string (DOC_SINK_CAPS);
  gst_pad_template_set_documentation_caps (pad_templ, doc_caps);
  gst_caps_unref (doc_caps);
  gst_element_class_add_pad_template (element_class, pad_templ);

  pad_templ = gst_pad_template_new ("src",
      GST_PAD_SRC, GST_PAD_ALWAYS, cdata->src_caps);
  doc_caps = gst_caps_from_string (DOC_SRC_CAPS);
  gst_pad_template_set_documentation_caps (pad_templ, doc_caps);
  gst_caps_unref (doc_caps);
  gst_element_class_add_pad_template (element_class, pad_templ);

  decoder_class->open = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_open);
  decoder_class->close = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_close);
  decoder_class->stop = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_stop);
  decoder_class->negotiate = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_negotiate);
  decoder_class->decide_allocation =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_decide_allocation);
  decoder_class->sink_query = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_sink_query);
  decoder_class->src_query = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_src_query);
  decoder_class->sink_event = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_sink_event);

  h265decoder_class->new_sequence =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_new_sequence);
  h265decoder_class->new_picture =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_new_picture);
  h265decoder_class->output_picture =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_output_picture);
  h265decoder_class->start_picture =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_start_picture);
  h265decoder_class->decode_slice =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_decode_slice);
  h265decoder_class->end_picture =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_end_picture);
  h265decoder_class->get_preferred_output_delay =
      GST_DEBUG_FUNCPTR (gst_nv_h265_dec_get_preferred_output_delay);

  klass->cuda_device_id = cdata->cuda_device_id;
  klass->adapter_luid = cdata->adapter_luid;
  klass->max_width = cdata->max_width;
  klass->max_height = cdata->max_height;

  gst_caps_unref (cdata->sink_caps);
  gst_caps_unref (cdata->src_caps);
  g_free (cdata);
}

static void
gst_nv_h265_dec_init (GstNvH265Dec * self)
{
  GstNvH265DecClass *klass = GST_NV_H265_DEC_GET_CLASS (self);

  self->decoder =
      gst_nv_decoder_new (klass->cuda_device_id, klass->adapter_luid);

  self->num_output_surfaces = DEFAULT_NUM_OUTPUT_SURFACES;
  self->max_display_delay = DEFAULT_MAX_DISPLAY_DELAY;
}

static void
gst_nv_h265_dec_finalize (GObject * object)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (object);

  gst_object_unref (self->decoder);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
gst_nv_h265_dec_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (object);

  switch (prop_id) {
    case PROP_NUM_OUTPUT_SURFACES:
      self->num_output_surfaces = g_value_get_uint (value);
      break;
    case PROP_INIT_MAX_WIDTH:
      self->init_max_width = g_value_get_uint (value);
      break;
    case PROP_INIT_MAX_HEIGHT:
      self->init_max_height = g_value_get_uint (value);
      break;
    case PROP_MAX_DISPLAY_DELAY:
      self->max_display_delay = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_nv_h265_dec_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (object);
  GstNvH265DecClass *klass = GST_NV_H265_DEC_GET_CLASS (object);

  switch (prop_id) {
    case PROP_CUDA_DEVICE_ID:
      g_value_set_uint (value, klass->cuda_device_id);
      break;
    case PROP_NUM_OUTPUT_SURFACES:
      g_value_set_uint (value, self->num_output_surfaces);
      break;
    case PROP_INIT_MAX_WIDTH:
      g_value_set_uint (value, self->init_max_width);
      break;
    case PROP_INIT_MAX_HEIGHT:
      g_value_set_uint (value, self->init_max_height);
      break;
    case PROP_MAX_DISPLAY_DELAY:
      g_value_set_int (value, self->max_display_delay);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_nv_h265_dec_set_context (GstElement * element, GstContext * context)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (element);

  gst_nv_decoder_handle_set_context (self->decoder, element, context);

  GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
}

static void
gst_nv_h265_dec_reset (GstNvH265Dec * self)
{
  self->width = 0;
  self->height = 0;
  self->coded_width = 0;
  self->coded_height = 0;
  self->bitdepth = 0;
  self->chroma_format_idc = 0;
  self->max_dpb_size = 0;
}

static gboolean
gst_nv_h265_dec_open (GstVideoDecoder * decoder)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  gst_nv_h265_dec_reset (self);

  return gst_nv_decoder_open (self->decoder, GST_ELEMENT (decoder));
}

static gboolean
gst_nv_h265_dec_close (GstVideoDecoder * decoder)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  g_clear_pointer (&self->bitstream_buffer, g_free);
  g_clear_pointer (&self->slice_offsets, g_free);

  self->bitstream_buffer_alloc_size = 0;
  self->slice_offsets_alloc_len = 0;

  return gst_nv_decoder_close (self->decoder);
}

static gboolean
gst_nv_h265_dec_stop (GstVideoDecoder * decoder)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  gboolean ret;

  ret = GST_VIDEO_DECODER_CLASS (parent_class)->stop (decoder);

  gst_nv_decoder_reset (self->decoder);

  return ret;
}

static gboolean
gst_nv_h265_dec_negotiate (GstVideoDecoder * decoder)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  GstH265Decoder *h265dec = GST_H265_DECODER (decoder);

  GST_DEBUG_OBJECT (self, "negotiate");

  if (!gst_nv_decoder_negotiate (self->decoder, decoder, h265dec->input_state))
    return FALSE;

  return GST_VIDEO_DECODER_CLASS (parent_class)->negotiate (decoder);
}

static gboolean
gst_nv_h265_dec_decide_allocation (GstVideoDecoder * decoder, GstQuery * query)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  if (!gst_nv_decoder_decide_allocation (self->decoder, decoder, query)) {
    GST_WARNING_OBJECT (self, "Failed to handle decide allocation");
    return FALSE;
  }

  return GST_VIDEO_DECODER_CLASS (parent_class)->decide_allocation
      (decoder, query);
}

static gboolean
gst_nv_h265_dec_sink_query (GstVideoDecoder * decoder, GstQuery * query)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  if (gst_nv_decoder_handle_query (self->decoder, GST_ELEMENT (decoder), query))
    return TRUE;

  return GST_VIDEO_DECODER_CLASS (parent_class)->sink_query (decoder, query);
}

static gboolean
gst_nv_h265_dec_src_query (GstVideoDecoder * decoder, GstQuery * query)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  if (gst_nv_decoder_handle_query (self->decoder, GST_ELEMENT (decoder), query))
    return TRUE;

  return GST_VIDEO_DECODER_CLASS (parent_class)->src_query (decoder, query);
}

static gboolean
gst_nv_h265_dec_sink_event (GstVideoDecoder * decoder, GstEvent * event)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_FLUSH_START:
      gst_nv_decoder_set_flushing (self->decoder, TRUE);
      break;
    case GST_EVENT_FLUSH_STOP:
      gst_nv_decoder_set_flushing (self->decoder, FALSE);
      break;
    default:
      break;
  }

  return GST_VIDEO_DECODER_CLASS (parent_class)->sink_event (decoder, event);
}

static GstFlowReturn
gst_nv_h265_dec_new_sequence (GstH265Decoder * decoder, const GstH265SPS * sps,
    gint max_dpb_size)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  GstNvH265DecClass *klass = GST_NV_H265_DEC_GET_CLASS (self);
  guint crop_width, crop_height;
  gboolean modified = FALSE;
  guint max_width, max_height;
  GstVideoFormat out_format = GST_VIDEO_FORMAT_UNKNOWN;
  gboolean is_gbr = FALSE;
  const GstH265VUIParams *vui = &sps->vui_params;

  GST_LOG_OBJECT (self, "new sequence");

  if (sps->conformance_window_flag) {
    crop_width = sps->crop_rect_width;
    crop_height = sps->crop_rect_height;
  } else {
    crop_width = sps->width;
    crop_height = sps->height;
  }

  if (self->width != crop_width || self->height != crop_height ||
      self->coded_width != (guint) sps->width ||
      self->coded_height != (guint) sps->height) {
    GST_INFO_OBJECT (self, "resolution changed %dx%d (%dx%d)",
        crop_width, crop_height, sps->width, sps->height);
    self->width = crop_width;
    self->height = crop_height;
    self->coded_width = sps->width;
    self->coded_height = sps->height;
    modified = TRUE;
  }

  if (self->bitdepth != (guint) sps->bit_depth_luma_minus8 + 8) {
    GST_INFO_OBJECT (self, "bitdepth changed");
    self->bitdepth = sps->bit_depth_luma_minus8 + 8;
    modified = TRUE;
  }

  if (self->chroma_format_idc != sps->chroma_format_idc) {
    GST_INFO_OBJECT (self, "chroma format changed");
    self->chroma_format_idc = sps->chroma_format_idc;
    modified = TRUE;
  }

  if (self->max_dpb_size < max_dpb_size) {
    GST_INFO_OBJECT (self, "Requires larger DPB size (%d -> %d)",
        self->max_dpb_size, max_dpb_size);
    modified = TRUE;
  }

  if (sps->chroma_format_idc == 3 && vui->colour_description_present_flag &&
      gst_video_color_matrix_from_iso (vui->matrix_coefficients) ==
      GST_VIDEO_COLOR_MATRIX_RGB) {
    is_gbr = TRUE;
  }

  switch (self->bitdepth) {
    case 8:
      if (self->chroma_format_idc == 1)
        out_format = GST_VIDEO_FORMAT_NV12;
      else if (self->chroma_format_idc == 3)
        out_format = is_gbr ? GST_VIDEO_FORMAT_GBR : GST_VIDEO_FORMAT_Y444;
      break;
    case 10:
      if (self->chroma_format_idc == 1) {
        out_format = GST_VIDEO_FORMAT_P010_10LE;
      } else if (self->chroma_format_idc == 3) {
        out_format = is_gbr ?
            GST_VIDEO_FORMAT_GBR_16LE : GST_VIDEO_FORMAT_Y444_16LE;
      }
      break;
    case 12:
      if (self->chroma_format_idc == 1) {
        out_format = GST_VIDEO_FORMAT_P012_LE;
      } else if (self->chroma_format_idc == 3) {
        out_format = is_gbr ?
            GST_VIDEO_FORMAT_GBR_16LE : GST_VIDEO_FORMAT_Y444_16LE;
      }
      break;
    default:
      break;
  }

  if (out_format == GST_VIDEO_FORMAT_UNKNOWN) {
    GST_ERROR_OBJECT (self,
        "Could not support bitdepth (%d) / chroma (%d) format", self->bitdepth,
        self->chroma_format_idc);
    return GST_FLOW_NOT_NEGOTIATED;
  }

  if (self->out_format != out_format) {
    if (self->out_format != GST_VIDEO_FORMAT_UNKNOWN) {
      GST_INFO_OBJECT (self, "Output format changed %s -> %s",
          gst_video_format_to_string (self->out_format),
          gst_video_format_to_string (out_format));
    }
    self->out_format = out_format;
    modified = TRUE;
  }

  if (modified || !gst_nv_decoder_is_configured (self->decoder)) {
    GstVideoInfo info;

    gst_video_info_set_format (&info,
        self->out_format, self->width, self->height);

    self->max_dpb_size = max_dpb_size;
    max_width = gst_nv_decoder_get_max_output_size (self->coded_width,
        self->init_max_width, klass->max_width);
    max_height = gst_nv_decoder_get_max_output_size (self->coded_height,
        self->init_max_height, klass->max_height);

    if (!gst_nv_decoder_configure (self->decoder,
            cudaVideoCodec_HEVC, &info, self->coded_width, self->coded_height,
            self->bitdepth, max_dpb_size, FALSE, self->num_output_surfaces,
            max_width, max_height)) {
      GST_ERROR_OBJECT (self, "Failed to configure decoder");
      return GST_FLOW_NOT_NEGOTIATED;
    }

    if (!gst_video_decoder_negotiate (GST_VIDEO_DECODER (self))) {
      GST_ERROR_OBJECT (self, "Failed to negotiate with downstream");
      return GST_FLOW_NOT_NEGOTIATED;
    }

    memset (&self->params, 0, sizeof (CUVIDPICPARAMS));
  }

  return GST_FLOW_OK;
}

static GstFlowReturn
gst_nv_h265_dec_new_picture (GstH265Decoder * decoder,
    GstVideoCodecFrame * cframe, GstH265Picture * picture)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  return gst_nv_decoder_new_picture (self->decoder,
      GST_CODEC_PICTURE (picture));
}

static GstFlowReturn
gst_nv_h265_dec_output_picture (GstH265Decoder * decoder,
    GstVideoCodecFrame * frame, GstH265Picture * picture)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  return gst_nv_decoder_output_picture (self->decoder,
      GST_VIDEO_DECODER (decoder), frame, GST_CODEC_PICTURE (picture),
      picture->buffer_flags);
}

static GstNvDecSurface *
gst_nv_h265_dec_get_decoder_surface_from_picture (GstNvH265Dec * self,
    GstH265Picture * picture)
{
  GstNvDecSurface *surface;

  surface = (GstNvDecSurface *) gst_h265_picture_get_user_data (picture);
  if (!surface)
    GST_DEBUG_OBJECT (self, "current picture does not have decoder frame");

  return surface;
}

static void
gst_nv_h265_dec_picture_params_from_sps (GstNvH265Dec * self,
    const GstH265SPS * sps, CUVIDHEVCPICPARAMS * params)
{
#define COPY_FIELD(f) \
  (params)->f = (sps)->f
#define COPY_FIELD_WITH_PREFIX(f) \
  (params)->G_PASTE(sps_,f) = (sps)->f
#define COPY_FIELD_EXTENSION(f) \
  (params)->f = (sps)->sps_extension_params.f

  params->pic_width_in_luma_samples = sps->width;
  params->pic_height_in_luma_samples = sps->height;
  COPY_FIELD (log2_min_luma_coding_block_size_minus3);
  COPY_FIELD (log2_diff_max_min_luma_coding_block_size);
  COPY_FIELD (log2_min_transform_block_size_minus2);
  COPY_FIELD (log2_diff_max_min_transform_block_size);
  COPY_FIELD (pcm_enabled_flag);
  COPY_FIELD (log2_min_pcm_luma_coding_block_size_minus3);
  COPY_FIELD (log2_diff_max_min_pcm_luma_coding_block_size);
  COPY_FIELD (pcm_sample_bit_depth_luma_minus1);
  COPY_FIELD (pcm_sample_bit_depth_chroma_minus1);
  COPY_FIELD (pcm_loop_filter_disabled_flag);
  COPY_FIELD (strong_intra_smoothing_enabled_flag);
  COPY_FIELD (max_transform_hierarchy_depth_intra);
  COPY_FIELD (max_transform_hierarchy_depth_inter);
  COPY_FIELD (max_transform_hierarchy_depth_inter);
  COPY_FIELD (amp_enabled_flag);
  COPY_FIELD (separate_colour_plane_flag);
  COPY_FIELD (log2_max_pic_order_cnt_lsb_minus4);
  COPY_FIELD (num_short_term_ref_pic_sets);
  COPY_FIELD (long_term_ref_pics_present_flag);
  COPY_FIELD (num_long_term_ref_pics_sps);
  COPY_FIELD_WITH_PREFIX (temporal_mvp_enabled_flag);
  COPY_FIELD (sample_adaptive_offset_enabled_flag);

  params->scaling_list_enable_flag = sps->scaling_list_enabled_flag;

  COPY_FIELD (bit_depth_luma_minus8);
  COPY_FIELD (bit_depth_chroma_minus8);

  /* Extension fields */
  COPY_FIELD (sps_range_extension_flag);
  if (sps->sps_range_extension_flag) {
    COPY_FIELD_EXTENSION (high_precision_offsets_enabled_flag);
    COPY_FIELD_EXTENSION (transform_skip_rotation_enabled_flag);
    COPY_FIELD_EXTENSION (implicit_rdpcm_enabled_flag);
    COPY_FIELD_EXTENSION (explicit_rdpcm_enabled_flag);
    COPY_FIELD_EXTENSION (extended_precision_processing_flag);
    COPY_FIELD_EXTENSION (intra_smoothing_disabled_flag);
    COPY_FIELD_EXTENSION (persistent_rice_adaptation_enabled_flag);
    COPY_FIELD_EXTENSION (cabac_bypass_alignment_enabled_flag);
  }
#undef COPY_FIELD
#undef COPY_FIELD_WITH_PREFIX
#undef COPY_FIELD_EXTENSION
}

static gboolean
gst_nv_h265_dec_picture_params_from_pps (GstNvH265Dec * self,
    const GstH265PPS * pps, CUVIDHEVCPICPARAMS * params)
{
  guint i;

#define COPY_FIELD(f) \
  (params)->f = (pps)->f
#define COPY_FIELD_WITH_PREFIX(f) \
  (params)->G_PASTE(pps_,f) = (pps)->f
#define COPY_FIELD_EXTENSION(f) \
  (params)->f = (pps)->pps_extension_params.f

  COPY_FIELD (dependent_slice_segments_enabled_flag);
  COPY_FIELD (slice_segment_header_extension_present_flag);
  COPY_FIELD (sign_data_hiding_enabled_flag);
  COPY_FIELD (cu_qp_delta_enabled_flag);
  COPY_FIELD (diff_cu_qp_delta_depth);
  COPY_FIELD (init_qp_minus26);
  COPY_FIELD_WITH_PREFIX (cb_qp_offset);
  COPY_FIELD_WITH_PREFIX (cr_qp_offset);
  COPY_FIELD (constrained_intra_pred_flag);
  COPY_FIELD (weighted_pred_flag);
  COPY_FIELD (weighted_bipred_flag);
  COPY_FIELD (transform_skip_enabled_flag);
  COPY_FIELD (transquant_bypass_enabled_flag);
  COPY_FIELD (entropy_coding_sync_enabled_flag);
  COPY_FIELD (log2_parallel_merge_level_minus2);
  COPY_FIELD (num_extra_slice_header_bits);
  COPY_FIELD (loop_filter_across_tiles_enabled_flag);
  COPY_FIELD (loop_filter_across_slices_enabled_flag);
  COPY_FIELD (output_flag_present_flag);
  COPY_FIELD (num_ref_idx_l0_default_active_minus1);
  COPY_FIELD (num_ref_idx_l1_default_active_minus1);
  COPY_FIELD (lists_modification_present_flag);
  COPY_FIELD (cabac_init_present_flag);
  COPY_FIELD_WITH_PREFIX (slice_chroma_qp_offsets_present_flag);
  COPY_FIELD (deblocking_filter_override_enabled_flag);
  COPY_FIELD_WITH_PREFIX (deblocking_filter_disabled_flag);
  COPY_FIELD_WITH_PREFIX (beta_offset_div2);
  COPY_FIELD_WITH_PREFIX (tc_offset_div2);
  COPY_FIELD (tiles_enabled_flag);
  COPY_FIELD (uniform_spacing_flag);

  if (pps->tiles_enabled_flag) {
    guint num_tile_columns;
    guint num_tile_rows;

    COPY_FIELD (num_tile_columns_minus1);
    COPY_FIELD (num_tile_rows_minus1);

    if (pps->num_tile_columns_minus1 >
        G_N_ELEMENTS (params->column_width_minus1)) {
      GST_ERROR_OBJECT (self,
          "Too large column_width_minus1 %d", pps->num_tile_columns_minus1);
      return FALSE;
    }

    if (pps->num_tile_rows_minus1 > G_N_ELEMENTS (params->row_height_minus1)) {
      GST_ERROR_OBJECT (self,
          "Too large num_tile_rows_minus1 %d", pps->num_tile_rows_minus1);
      return FALSE;
    }

    /* XXX: The size of column_width_minus1 array in CUVIDHEVCPICPARAMS struct
     * is 21 which is inconsistent with the spec.
     * Just copy values as many as possible */
    num_tile_columns = MIN (pps->num_tile_columns_minus1,
        G_N_ELEMENTS (pps->column_width_minus1));
    num_tile_rows = MIN (pps->num_tile_rows_minus1,
        G_N_ELEMENTS (pps->row_height_minus1));

    for (i = 0; i < num_tile_columns; i++)
      COPY_FIELD (column_width_minus1[i]);

    for (i = 0; i < num_tile_rows; i++)
      COPY_FIELD (row_height_minus1[i]);
  }

  COPY_FIELD (pps_range_extension_flag);
  if (pps->pps_range_extension_flag) {
    COPY_FIELD_EXTENSION (cross_component_prediction_enabled_flag);
    COPY_FIELD_EXTENSION (chroma_qp_offset_list_enabled_flag);
    COPY_FIELD_EXTENSION (diff_cu_chroma_qp_offset_depth);
    COPY_FIELD_EXTENSION (chroma_qp_offset_list_len_minus1);
    for (i = 0; i < G_N_ELEMENTS (params->cb_qp_offset_list); i++)
      COPY_FIELD_EXTENSION (cb_qp_offset_list[i]);
    for (i = 0; i < G_N_ELEMENTS (params->cr_qp_offset_list); i++)
      COPY_FIELD_EXTENSION (cr_qp_offset_list[i]);
    COPY_FIELD_EXTENSION (log2_sao_offset_scale_luma);
    COPY_FIELD_EXTENSION (log2_sao_offset_scale_chroma);
  }
#undef COPY_FIELD
#undef COPY_FIELD_WITH_PREFIX
#undef COPY_FIELD_EXTENSION

  return TRUE;
}

static void
gst_nv_h265_dec_reset_bitstream_params (GstNvH265Dec * self)
{
  self->bitstream_buffer_offset = 0;
  self->num_slices = 0;

  self->params.nBitstreamDataLen = 0;
  self->params.pBitstreamData = nullptr;
  self->params.nNumSlices = 0;
  self->params.pSliceDataOffsets = nullptr;
}

static GstFlowReturn
gst_nv_h265_dec_start_picture (GstH265Decoder * decoder,
    GstH265Picture * picture, GstH265Slice * slice, GstH265Dpb * dpb)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  CUVIDPICPARAMS *params = &self->params;
  CUVIDHEVCPICPARAMS *h265_params = &params->CodecSpecific.hevc;
  const GstH265SliceHdr *slice_header = &slice->header;
  const GstH265SPS *sps;
  const GstH265PPS *pps;
  GstNvDecSurface *surface;
  GArray *dpb_array;
  guint num_ref_pic;
  guint i, j, k;
  const GstH265ScalingList *scaling_list = nullptr;

  /* both NVDEC and h265parser are using the same order */
  G_STATIC_ASSERT (sizeof (scaling_list->scaling_lists_4x4) ==
      sizeof (h265_params->ScalingList4x4));
  G_STATIC_ASSERT (sizeof (scaling_list->scaling_lists_8x8) ==
      sizeof (h265_params->ScalingList8x8));
  G_STATIC_ASSERT (sizeof (scaling_list->scaling_lists_16x16) ==
      sizeof (h265_params->ScalingList16x16));
  G_STATIC_ASSERT (sizeof (scaling_list->scaling_lists_32x32) ==
      sizeof (h265_params->ScalingList32x32));

  g_return_val_if_fail (slice_header->pps != nullptr, GST_FLOW_ERROR);
  g_return_val_if_fail (slice_header->pps->sps != nullptr, GST_FLOW_ERROR);

  surface = gst_nv_h265_dec_get_decoder_surface_from_picture (self, picture);
  if (!surface) {
    GST_ERROR_OBJECT (self,
        "Couldn't get decoder surface frame picture %p", picture);
    return GST_FLOW_ERROR;
  }

  gst_nv_h265_dec_reset_bitstream_params (self);

  pps = slice_header->pps;
  sps = pps->sps;

  /* FIXME: update sps/pps related params only when it's required */
  params->PicWidthInMbs = sps->pic_width_in_luma_samples / 16;
  params->FrameHeightInMbs = sps->pic_height_in_luma_samples / 16;
  params->CurrPicIdx = surface->index;

  /* nBitstreamDataLen, pBitstreamData, nNumSlices and pSliceDataOffsets
   * will be set later */
  params->ref_pic_flag = picture->ref;
  params->intra_pic_flag = GST_H265_IS_NAL_TYPE_IRAP (slice->nalu.type);

  h265_params->IrapPicFlag = GST_H265_IS_NAL_TYPE_IRAP (slice->nalu.type);
  h265_params->IdrPicFlag = GST_H265_IS_NAL_TYPE_IDR (slice->nalu.type);

  gst_nv_h265_dec_picture_params_from_sps (self, sps, h265_params);
  if (!gst_nv_h265_dec_picture_params_from_pps (self, pps, h265_params)) {
    GST_ERROR_OBJECT (self, "Couldn't copy pps");
    return GST_FLOW_ERROR;
  }

  /* Fill reference */
  if (decoder->NumPocStCurrBefore >
      G_N_ELEMENTS (h265_params->RefPicSetStCurrBefore)) {
    GST_ERROR_OBJECT (self, "Too many RefPicSetStCurrBefore");
    return GST_FLOW_ERROR;
  }

  if (decoder->NumPocStCurrAfter >
      G_N_ELEMENTS (h265_params->RefPicSetStCurrAfter)) {
    GST_ERROR_OBJECT (self, "Too many RefPicSetStCurrAfter");
    return GST_FLOW_ERROR;
  }

  if (decoder->NumPocLtCurr > G_N_ELEMENTS (h265_params->RefPicSetLtCurr)) {
    GST_ERROR_OBJECT (self, "Too many RefPicSetLtCurr");
    return GST_FLOW_ERROR;
  }

  /* Fill ref list */
  h265_params->NumBitsForShortTermRPSInSlice =
      slice_header->short_term_ref_pic_set_size;
  h265_params->NumDeltaPocsOfRefRpsIdx =
      slice_header->short_term_ref_pic_sets.NumDeltaPocsOfRefRpsIdx;
  h265_params->NumPocTotalCurr = decoder->NumPicTotalCurr;
  h265_params->NumPocStCurrBefore = decoder->NumPocStCurrBefore;
  h265_params->NumPocStCurrAfter = decoder->NumPocStCurrAfter;
  h265_params->NumPocLtCurr = decoder->NumPocLtCurr;
  h265_params->CurrPicOrderCntVal = picture->pic_order_cnt;

  dpb_array = gst_h265_dpb_get_pictures_all (dpb);
  /* count only referenced frame */
  num_ref_pic = 0;
  for (i = 0; i < dpb_array->len; i++) {
    GstH265Picture *other = g_array_index (dpb_array, GstH265Picture *, i);
    GstNvDecSurface *other_surface;
    gint picture_index = -1;

    if (!other->ref)
      continue;

    if (num_ref_pic >= G_N_ELEMENTS (h265_params->RefPicIdx)) {
      GST_ERROR_OBJECT (self, "Too many reference frames");
      return GST_FLOW_ERROR;
    }

    other_surface =
        gst_nv_h265_dec_get_decoder_surface_from_picture (self, other);
    if (other_surface)
      picture_index = other_surface->index;

    h265_params->RefPicIdx[num_ref_pic] = picture_index;
    h265_params->PicOrderCntVal[num_ref_pic] = other->pic_order_cnt;
    h265_params->IsLongTerm[num_ref_pic] = other->long_term;

    num_ref_pic++;
  }
  g_array_unref (dpb_array);

  for (i = 0, j = 0; i < num_ref_pic; i++) {
    GstH265Picture *other = nullptr;

    while (!other && j < decoder->NumPocStCurrBefore)
      other = decoder->RefPicSetStCurrBefore[j++];

    if (other) {
      for (k = 0; k < num_ref_pic; k++) {
        if (h265_params->PicOrderCntVal[k] == other->pic_order_cnt) {
          h265_params->RefPicSetStCurrBefore[i] = k;
          break;
        }
      }
    }
  }

  for (i = 0, j = 0; i < num_ref_pic; i++) {
    GstH265Picture *other = nullptr;

    while (!other && j < decoder->NumPocStCurrAfter)
      other = decoder->RefPicSetStCurrAfter[j++];

    if (other) {
      for (k = 0; k < num_ref_pic; k++) {
        if (h265_params->PicOrderCntVal[k] == other->pic_order_cnt) {
          h265_params->RefPicSetStCurrAfter[i] = k;
          break;
        }
      }
    }
  }

  for (i = 0, j = 0; i < num_ref_pic; i++) {
    GstH265Picture *other = nullptr;

    while (!other && j < decoder->NumPocLtCurr)
      other = decoder->RefPicSetLtCurr[j++];

    if (other) {
      for (k = 0; k < num_ref_pic; k++) {
        if (h265_params->PicOrderCntVal[k] == other->pic_order_cnt) {
          h265_params->RefPicSetLtCurr[i] = k;
          break;
        }
      }
    }
  }

  /* Fill scaling list */
  if (pps->scaling_list_data_present_flag ||
      (sps->scaling_list_enabled_flag
          && !sps->scaling_list_data_present_flag)) {
    scaling_list = &pps->scaling_list;
  } else {
    scaling_list = &sps->scaling_list;
  }

  memcpy (h265_params->ScalingList4x4, scaling_list->scaling_lists_4x4,
      sizeof (scaling_list->scaling_lists_4x4));
  memcpy (h265_params->ScalingList8x8, scaling_list->scaling_lists_8x8,
      sizeof (scaling_list->scaling_lists_8x8));
  memcpy (h265_params->ScalingList16x16, scaling_list->scaling_lists_16x16,
      sizeof (scaling_list->scaling_lists_16x16));
  memcpy (h265_params->ScalingList32x32, scaling_list->scaling_lists_32x32,
      sizeof (scaling_list->scaling_lists_32x32));

  for (i = 0; i < G_N_ELEMENTS (h265_params->ScalingListDCCoeff16x16); i++) {
    h265_params->ScalingListDCCoeff16x16[i] =
        scaling_list->scaling_list_dc_coef_minus8_16x16[i] + 8;
  }

  for (i = 0; i < G_N_ELEMENTS (h265_params->ScalingListDCCoeff32x32); i++) {
    h265_params->ScalingListDCCoeff32x32[i] =
        scaling_list->scaling_list_dc_coef_minus8_32x32[i] + 8;
  }

  return GST_FLOW_OK;
}

static GstFlowReturn
gst_nv_h265_dec_decode_slice (GstH265Decoder * decoder,
    GstH265Picture * picture, GstH265Slice * slice,
    GArray * ref_pic_list0, GArray * ref_pic_list1)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  gsize new_size;

  GST_LOG_OBJECT (self, "Decode slice, nalu size %u", slice->nalu.size);

  if (self->slice_offsets_alloc_len < self->num_slices + 1) {
    self->slice_offsets_alloc_len = 2 * (self->num_slices + 1);

    self->slice_offsets = (guint *) g_realloc_n (self->slice_offsets,
        self->slice_offsets_alloc_len, sizeof (guint));
  }
  self->slice_offsets[self->num_slices] = self->bitstream_buffer_offset;
  GST_LOG_OBJECT (self, "Slice offset %u for slice %d",
      self->slice_offsets[self->num_slices], self->num_slices);

  self->num_slices++;

  new_size = self->bitstream_buffer_offset + slice->nalu.size + 3;
  if (self->bitstream_buffer_alloc_size < new_size) {
    self->bitstream_buffer_alloc_size = 2 * new_size;

    self->bitstream_buffer = (guint8 *) g_realloc (self->bitstream_buffer,
        self->bitstream_buffer_alloc_size);
  }

  self->bitstream_buffer[self->bitstream_buffer_offset] = 0;
  self->bitstream_buffer[self->bitstream_buffer_offset + 1] = 0;
  self->bitstream_buffer[self->bitstream_buffer_offset + 2] = 1;

  memcpy (self->bitstream_buffer + self->bitstream_buffer_offset + 3,
      slice->nalu.data + slice->nalu.offset, slice->nalu.size);
  self->bitstream_buffer_offset = new_size;

  return GST_FLOW_OK;
}

static GstFlowReturn
gst_nv_h265_dec_end_picture (GstH265Decoder * decoder, GstH265Picture * picture)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
  gboolean ret;
  CUVIDPICPARAMS *params = &self->params;

  params->nBitstreamDataLen = self->bitstream_buffer_offset;
  params->pBitstreamData = self->bitstream_buffer;
  params->nNumSlices = self->num_slices;
  params->pSliceDataOffsets = self->slice_offsets;

  GST_LOG_OBJECT (self, "End picture, bitstream len: %" G_GSIZE_FORMAT
      ", num slices %d", self->bitstream_buffer_offset, self->num_slices);

  ret = gst_nv_decoder_decode (self->decoder, &self->params);

  if (!ret) {
    GST_ERROR_OBJECT (self, "Failed to decode picture");
    return GST_FLOW_ERROR;
  }

  return GST_FLOW_OK;
}

static guint
gst_nv_h265_dec_get_preferred_output_delay (GstH265Decoder * decoder,
    gboolean live)
{
  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);

  if (self->max_display_delay >= 0)
    return self->max_display_delay;

  /* Prefer to zero latency for live pipeline */
  if (live)
    return 0;

  return 2;
}

void
gst_nv_h265_dec_register (GstPlugin * plugin, guint device_id,
    gint64 adapter_luid, guint rank, GstCaps * sink_caps, GstCaps * src_caps)
{
  GType type;
  gchar *type_name;
  gchar *feature_name;
  GstNvDecoderClassData *cdata;
  gint index = 0;
  GValue value_list = G_VALUE_INIT;
  GValue value = G_VALUE_INIT;
  GstStructure *s;
  const GValue *res_val;
  GTypeInfo type_info = {
    sizeof (GstNvH265DecClass),
    nullptr,
    nullptr,
    (GClassInitFunc) gst_nv_h265_dec_class_init,
    nullptr,
    nullptr,
    sizeof (GstNvH265Dec),
    0,
    (GInstanceInitFunc) gst_nv_h265_dec_init,
  };

  GST_DEBUG_CATEGORY_INIT (gst_nv_h265_dec_debug, "nvh265dec", 0, "nvh265dec");

  cdata = g_new0 (GstNvDecoderClassData, 1);
  cdata->sink_caps = gst_caps_copy (sink_caps);

  s = gst_caps_get_structure (sink_caps, 0);
  res_val = gst_structure_get_value (s, "width");
  cdata->max_width = (guint) gst_value_get_int_range_max (res_val);

  res_val = gst_structure_get_value (s, "height");
  cdata->max_height = (guint) gst_value_get_int_range_max (res_val);

  /* Update stream-format since we support packetized format as well */
  g_value_init (&value_list, GST_TYPE_LIST);
  g_value_init (&value, G_TYPE_STRING);

  g_value_set_static_string (&value, "hev1");
  gst_value_list_append_value (&value_list, &value);

  g_value_set_static_string (&value, "hvc1");
  gst_value_list_append_value (&value_list, &value);

  g_value_set_static_string (&value, "byte-stream");
  gst_value_list_append_value (&value_list, &value);

  gst_caps_set_value (cdata->sink_caps, "stream-format", &value_list);
  g_value_unset (&value);
  g_value_unset (&value_list);

  GST_MINI_OBJECT_FLAG_SET (cdata->sink_caps,
      GST_MINI_OBJECT_FLAG_MAY_BE_LEAKED);
  cdata->src_caps = gst_caps_ref (src_caps);
  cdata->cuda_device_id = device_id;
  cdata->adapter_luid = adapter_luid;

  type_name = g_strdup ("GstNvH265Dec");
  feature_name = g_strdup ("nvh265dec");

  while (g_type_from_name (type_name)) {
    index++;
    g_free (type_name);
    g_free (feature_name);
    type_name = g_strdup_printf ("GstNvH265Device%dDec", index);
    feature_name = g_strdup_printf ("nvh265device%ddec", index);
  }

  type_info.class_data = cdata;
  type = g_type_register_static (GST_TYPE_H265_DECODER,
      type_name, &type_info, (GTypeFlags) 0);

  /* make lower rank than default device */
  if (rank > 0 && index > 0)
    rank--;

  if (!gst_element_register (plugin, feature_name, rank, type))
    GST_WARNING ("Failed to register plugin '%s'", type_name);

  g_free (type_name);
  g_free (feature_name);
}
