nvcodec: Add H265 stateless codec implementation

Add a new GstCodecs based H265 decoder element

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1357>

4 files changed, 1147 insertions, 11 deletions

diff --git a/sys/nvcodec/gstnvh265dec.c b/sys/nvcodec/gstnvh265dec.c
new file mode 100644
index 000000000..62575b03b
--- /dev/null
+++ b/sys/nvcodec/gstnvh265dec.c
@@ -0,0 +1,1068 @@
+/* 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstnvh265dec.h"
+#include "gstcudautils.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
+
+struct _GstNvH265Dec
+{
+  GstH265Decoder parent;
+
+  GstVideoCodecState *output_state;
+
+  const GstH265SPS *last_sps;
+  const GstH265PPS *last_pps;
+
+  GstCudaContext *context;
+  CUstream cuda_stream;
+  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;
+  GstVideoFormat out_format;
+
+  /* For OpenGL interop. */
+  GstObject *gl_display;
+  GstObject *gl_context;
+  GstObject *other_gl_context;
+
+  GstNvDecoderOutputType output_type;
+};
+
+struct _GstNvH265DecClass
+{
+  GstH265DecoderClass parent_class;
+  guint cuda_device_id;
+};
+
+#define gst_nv_h265_dec_parent_class parent_class
+G_DEFINE_TYPE (GstNvH265Dec, gst_nv_h265_dec, GST_TYPE_H265_DECODER);
+
+static void gst_nv_h265_decoder_finalize (GObject * object);
+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_negotiate (GstVideoDecoder * decoder);
+static gboolean gst_nv_h265_dec_decide_allocation (GstVideoDecoder *
+    decoder, GstQuery * query);
+static gboolean gst_nv_h265_dec_src_query (GstVideoDecoder * decoder,
+    GstQuery * query);
+
+/* GstH265Decoder */
+static gboolean gst_nv_h265_dec_new_sequence (GstH265Decoder * decoder,
+    const GstH265SPS * sps, gint max_dpb_size);
+static gboolean gst_nv_h265_dec_new_picture (GstH265Decoder * decoder,
+    GstH265Picture * picture);
+static GstFlowReturn gst_nv_h265_dec_output_picture (GstH265Decoder *
+    decoder, GstH265Picture * picture);
+static gboolean gst_nv_h265_dec_start_picture (GstH265Decoder * decoder,
+    GstH265Picture * picture, GstH265Slice * slice, GstH265Dpb * dpb);
+static gboolean gst_nv_h265_dec_decode_slice (GstH265Decoder * decoder,
+    GstH265Picture * picture, GstH265Slice * slice);
+static gboolean gst_nv_h265_dec_end_picture (GstH265Decoder * decoder,
+    GstH265Picture * picture);
+
+static void
+gst_nv_h265_dec_class_init (GstNvH265DecClass * klass)
+{
+  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_decoder_finalize;
+
+  element_class->set_context = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_set_context);
+
+  decoder_class->open = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_open);
+  decoder_class->close = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_close);
+  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->src_query = GST_DEBUG_FUNCPTR (gst_nv_h265_dec_src_query);
+
+  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);
+
+  GST_DEBUG_CATEGORY_INIT (gst_nv_h265_dec_debug,
+      "nvh265dec", 0, "Nvidia H.265 Decoder");
+
+  gst_type_mark_as_plugin_api (GST_TYPE_NV_H265_DEC, 0);
+}
+
+static void
+gst_nv_h265_dec_init (GstNvH265Dec * self)
+{
+}
+
+static void
+gst_nv_h265_decoder_finalize (GObject * object)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (object);
+
+  g_free (self->bitstream_buffer);
+  g_free (self->slice_offsets);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_nv_h265_dec_set_context (GstElement * element, GstContext * context)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (element);
+  GstNvH265DecClass *klass = GST_NV_H265_DEC_GET_CLASS (self);
+
+  GST_DEBUG_OBJECT (self, "set context %s",
+      gst_context_get_context_type (context));
+
+  gst_nv_decoder_set_context (element, context, klass->cuda_device_id,
+      &self->context, &self->gl_display, &self->other_gl_context);
+
+  GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
+}
+
+static gboolean
+gst_nv_h265_dec_open (GstVideoDecoder * decoder)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+  GstNvH265DecClass *klass = GST_NV_H265_DEC_GET_CLASS (self);
+
+  if (!gst_nv_decoder_ensure_element_data (GST_ELEMENT (self),
+          klass->cuda_device_id, &self->context, &self->cuda_stream,
+          &self->gl_display, &self->other_gl_context)) {
+    GST_ERROR_OBJECT (self, "Required element data is unavailable");
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_nv_h265_dec_close (GstVideoDecoder * decoder)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+
+  g_clear_pointer (&self->output_state, gst_video_codec_state_unref);
+  gst_clear_object (&self->decoder);
+
+  if (self->context && self->cuda_stream) {
+    if (gst_cuda_context_push (self->context)) {
+      gst_cuda_result (CuStreamDestroy (self->cuda_stream));
+      gst_cuda_context_pop (NULL);
+    }
+  }
+
+  gst_clear_object (&self->gl_context);
+  gst_clear_object (&self->other_gl_context);
+  gst_clear_object (&self->gl_display);
+  gst_clear_object (&self->context);
+  self->cuda_stream = NULL;
+
+  return TRUE;
+}
+
+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");
+
+  gst_nv_decoder_negotiate (decoder, h265dec->input_state, self->out_format,
+      self->width, self->height, self->gl_display, self->other_gl_context,
+      &self->gl_context, &self->output_state, &self->output_type);
+
+  /* TODO: add support D3D11 memory */
+
+  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);
+
+  gst_nv_decoder_decide_allocation (decoder, query,
+      self->gl_context, self->output_type);
+
+  return GST_VIDEO_DECODER_CLASS (parent_class)->decide_allocation
+      (decoder, query);
+}
+
+static gboolean
+gst_nv_h265_dec_src_query (GstVideoDecoder * decoder, GstQuery * query)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_CONTEXT:
+      if (gst_nv_decoder_handle_context_query (GST_ELEMENT (self), query,
+              self->context, self->gl_display, self->gl_context,
+              self->other_gl_context)) {
+        return TRUE;
+      }
+      break;
+    default:
+      break;
+  }
+
+  return GST_VIDEO_DECODER_CLASS (parent_class)->src_query (decoder, query);
+}
+
+static gboolean
+gst_nv_h265_dec_new_sequence (GstH265Decoder * decoder, const GstH265SPS * sps,
+    gint max_dpb_size)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+  gint crop_width, crop_height;
+  gboolean modified = FALSE;
+
+  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 != sps->width || self->coded_height != 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 != 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 (modified || !self->decoder) {
+    GstVideoInfo info;
+
+    self->out_format = GST_VIDEO_FORMAT_UNKNOWN;
+
+    if (self->bitdepth == 8) {
+      if (self->chroma_format_idc == 1)
+        self->out_format = GST_VIDEO_FORMAT_NV12;
+      else {
+        GST_FIXME_OBJECT (self, "Could not support 8bits non-4:2:0 format");
+      }
+    } else if (self->bitdepth == 10) {
+      if (self->chroma_format_idc == 1)
+        self->out_format = GST_VIDEO_FORMAT_P010_10LE;
+      else {
+        GST_FIXME_OBJECT (self, "Could not support 10bits non-4:2:0 format");
+      }
+    }
+
+    if (self->out_format == GST_VIDEO_FORMAT_UNKNOWN) {
+      GST_ERROR_OBJECT (self, "Could not support bitdepth/chroma format");
+      return FALSE;
+    }
+
+    gst_clear_object (&self->decoder);
+
+    gst_video_info_set_format (&info,
+        self->out_format, self->width, self->height);
+
+    self->decoder = gst_nv_decoder_new (self->context, cudaVideoCodec_HEVC,
+        &info,
+        /* Additional 2 buffers for margin */
+        max_dpb_size + 2);
+
+    if (!self->decoder) {
+      GST_ERROR_OBJECT (self, "Failed to create decoder");
+      return FALSE;
+    }
+
+    if (!gst_video_decoder_negotiate (GST_VIDEO_DECODER (self))) {
+      GST_ERROR_OBJECT (self, "Failed to negotiate with downstream");
+      return FALSE;
+    }
+
+    self->last_sps = NULL;
+    self->last_pps = NULL;
+    memset (&self->params, 0, sizeof (CUVIDPICPARAMS));
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_nv_h265_dec_new_picture (GstH265Decoder * decoder, GstH265Picture * picture)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+  GstNvDecoderFrame *frame;
+
+  frame = gst_nv_decoder_new_frame (self->decoder);
+  if (!frame) {
+    GST_ERROR_OBJECT (self, "No available decoder frame");
+    return FALSE;
+  }
+
+  GST_LOG_OBJECT (self, "New decoder frame %p (index %d)", frame, frame->index);
+
+  gst_h265_picture_set_user_data (picture,
+      frame, (GDestroyNotify) gst_nv_decoder_frame_free);
+
+  return TRUE;
+}
+
+static GstFlowReturn
+gst_nv_h265_dec_output_picture (GstH265Decoder * decoder,
+    GstH265Picture * picture)
+{
+  GstNvH265Dec *self = GST_NV_H265_DEC (decoder);
+  GstVideoCodecFrame *frame = NULL;
+  GstBuffer *output_buffer = NULL;
+  GstNvDecoderFrame *decoder_frame;
+  gboolean ret G_GNUC_UNUSED = FALSE;
+
+  GST_LOG_OBJECT (self,
+      "Outputting picture %p (poc %d)", picture, picture->pic_order_cnt);
+
+  decoder_frame =
+      (GstNvDecoderFrame *) gst_h265_picture_get_user_data (picture);
+  if (!decoder_frame) {
+    GST_ERROR_OBJECT (self, "No decoder frame in picture %p", picture);
+    return GST_FLOW_ERROR;
+  }
+
+  frame = gst_video_decoder_get_frame (GST_VIDEO_DECODER (self),
+      picture->system_frame_number);
+  if (!frame) {
+    GST_ERROR_OBJECT (self, "Failed to retrieve codec frame");
+    return GST_FLOW_ERROR;
+  }
+
+  output_buffer =
+      gst_video_decoder_allocate_output_buffer (GST_VIDEO_DECODER (self));
+  frame->output_buffer = output_buffer;
+
+  if (self->output_type == GST_NV_DECOCER_OUTPUT_TYPE_GL) {
+    ret = gst_nv_decoder_finish_frame (self->decoder,
+        GST_NV_DECOCER_OUTPUT_TYPE_GL, self->gl_context,
+        decoder_frame, output_buffer);
+
+    /* FIXME: This is the case where OpenGL context of downstream glbufferpool
+     * belongs to non-nvidia (or different device).
+     * There should be enhancement to ensure nvdec has compatible OpenGL context
+     */
+    if (!ret) {
+      GST_WARNING_OBJECT (self,
+          "Couldn't copy frame to GL memory, fallback to system memory");
+      self->output_type = GST_NV_DECOCER_OUTPUT_TYPE_SYSTEM;
+    }
+  }
+
+  if (!ret) {
+    if (!gst_nv_decoder_finish_frame (self->decoder,
+            GST_NV_DECOCER_OUTPUT_TYPE_SYSTEM, NULL, decoder_frame,
+            output_buffer)) {
+      GST_ERROR_OBJECT (self, "Failed to finish frame");
+      gst_video_decoder_drop_frame (GST_VIDEO_DECODER (self), frame);
+      return GST_FLOW_ERROR;
+    }
+  }
+
+  return gst_video_decoder_finish_frame (GST_VIDEO_DECODER (self), frame);
+}
+
+static GstNvDecoderFrame *
+gst_nv_h265_dec_get_decoder_frame_from_picture (GstNvH265Dec * self,
+    GstH265Picture * picture)
+{
+  GstNvDecoderFrame *frame;
+
+  frame = (GstNvDecoderFrame *) gst_h265_picture_get_user_data (picture);
+
+  if (!frame)
+    GST_DEBUG_OBJECT (self, "current picture does not have decoder frame");
+
+  return frame;
+}
+
+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_extnsion_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)
+{
+  gint 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);
+  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;
+  }
+
+  for (i = 0; i < pps->num_tile_columns_minus1 + 1; i++)
+    COPY_FIELD (column_width_minus1[i]);
+
+  for (i = 0; i < pps->num_tile_rows_minus1 + 1; 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 = NULL;
+  self->params.nNumSlices = 0;
+  self->params.pSliceDataOffsets = NULL;
+}
+
+static gboolean
+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;
+  GstNvDecoderFrame *frame;
+  GArray *dpb_array;
+  gint num_ref_pic;
+  gint i, j;
+  const GstH265ScalingList *scaling_list = NULL;
+
+  /* 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 != NULL, FALSE);
+  g_return_val_if_fail (slice_header->pps->sps != NULL, FALSE);
+
+  frame = gst_nv_h265_dec_get_decoder_frame_from_picture (self, picture);
+
+  if (!frame) {
+    GST_ERROR_OBJECT (self,
+        "Couldn't get decoder frame frame picture %p", picture);
+    return FALSE;
+  }
+
+  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 = frame->index;
+  /* TODO: verifiy interlaced */
+  params->field_pic_flag = picture->field != GST_H265_PICTURE_FIELD_FRAME;
+  params->bottom_field_flag =
+      picture->field == GST_H265_PICTURE_FIELD_BOTTOM_FIELD;
+  /* TODO: set second_field here */
+  params->second_field = 0;
+
+  /* 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);
+
+  if (!self->last_sps || self->last_sps != sps) {
+    GST_DEBUG_OBJECT (self, "Update params from SPS and PPS");
+    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 FALSE;
+    }
+    self->last_sps = sps;
+    self->last_pps = pps;
+  } else if (!self->last_pps || self->last_pps != pps) {
+    GST_DEBUG_OBJECT (self, "Update params from PPS");
+    if (!gst_nv_h265_dec_picture_params_from_pps (self, pps, h265_params)) {
+      GST_ERROR_OBJECT (self, "Couldn't copy pps");
+      return FALSE;
+    }
+    self->last_pps = pps;
+  } else {
+    GST_TRACE_OBJECT (self, "SPS and PPS were not updated");
+  }
+
+  /* Fill reference */
+  if (decoder->NumPocStCurrBefore >
+      G_N_ELEMENTS (h265_params->RefPicSetStCurrBefore)) {
+    GST_ERROR_OBJECT (self, "Too many RefPicSetStCurrBefore");
+    return FALSE;
+  }
+
+  if (decoder->NumPocStCurrAfter >
+      G_N_ELEMENTS (h265_params->RefPicSetStCurrAfter)) {
+    GST_ERROR_OBJECT (self, "Too many RefPicSetStCurrAfter");
+    return FALSE;
+  }
+
+  if (decoder->NumPocLtCurr > G_N_ELEMENTS (h265_params->RefPicSetLtCurr)) {
+    GST_ERROR_OBJECT (self, "Too many RefPicSetLtCurr");
+    return FALSE;
+  }
+
+  /* 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->NumPocTotalCurr;
+  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);
+    GstNvDecoderFrame *other_frame;
+    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 FALSE;
+    }
+
+    other_frame = gst_nv_h265_dec_get_decoder_frame_from_picture (self, other);
+
+    if (other_frame)
+      picture_index = other_frame->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 = num_ref_pic; i < G_N_ELEMENTS (h265_params->RefPicIdx); i++)
+    h265_params->RefPicIdx[i] = -1;
+
+  for (i = 0; i < decoder->NumPocStCurrBefore; i++) {
+    GstH265Picture *other;
+
+    if (!decoder->RefPicSetStCurrBefore[i]) {
+      GST_ERROR_OBJECT (self, "Empty RefPicSetStCurrBefore[%d]", i);
+      return FALSE;
+    }
+
+    other = decoder->RefPicSetStCurrBefore[i];
+
+    for (j = 0; j < num_ref_pic; j++) {
+      if (h265_params->PicOrderCntVal[j] == other->pic_order_cnt) {
+        h265_params->RefPicSetStCurrBefore[i] = j;
+        break;
+      }
+    }
+  }
+
+  for (i = 0; i < decoder->NumPocStCurrAfter; i++) {
+    GstH265Picture *other;
+
+    if (!decoder->RefPicSetStCurrAfter[i]) {
+      GST_ERROR_OBJECT (self, "Empty RefPicSetStCurrAfter[%d]", i);
+      return FALSE;
+    }
+
+    other = decoder->RefPicSetStCurrAfter[i];
+
+    for (j = 0; j < num_ref_pic; j++) {
+      if (h265_params->PicOrderCntVal[j] == other->pic_order_cnt) {
+        h265_params->RefPicSetStCurrAfter[i] = j;
+        break;
+      }
+    }
+  }
+
+  for (i = 0; i < decoder->NumPocLtCurr; i++) {
+    GstH265Picture *other;
+
+    if (!decoder->RefPicSetLtCurr[i]) {
+      GST_ERROR_OBJECT (self, "Empty RefPicSetLtCurr[%d]", i);
+      return FALSE;
+    }
+
+    other = decoder->RefPicSetLtCurr[i];
+
+    for (j = 0; j < num_ref_pic; j++) {
+      if (h265_params->PicOrderCntVal[j] == other->pic_order_cnt) {
+        h265_params->RefPicSetLtCurr[i] = j;
+        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 TRUE;
+}
+
+static gboolean
+gst_nv_h265_dec_decode_slice (GstH265Decoder * decoder,
+    GstH265Picture * picture, GstH265Slice * slice)
+{
+  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 = (guint *) g_realloc_n (self->slice_offsets,
+        self->num_slices + 1, 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 =
+        (guint8 *) g_realloc (self->bitstream_buffer, new_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 TRUE;
+}
+
+static gboolean
+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_picture (self->decoder, &self->params);
+
+  if (!ret)
+    GST_ERROR_OBJECT (self, "Failed to decode picture");
+
+  return ret;
+}
+
+typedef struct
+{
+  GstCaps *sink_caps;
+  GstCaps *src_caps;
+  guint cuda_device_id;
+  gboolean is_default;
+} GstNvH265DecClassData;
+
+static void
+gst_nv_h265_dec_subclass_init (gpointer klass, GstNvH265DecClassData * cdata)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
+  GstNvH265DecClass *nvdec_class = (GstNvH265DecClass *) (klass);
+  gchar *long_name;
+
+  if (cdata->is_default) {
+    long_name = g_strdup_printf ("NVDEC H.265 Stateless Decoder");
+  } else {
+    long_name = g_strdup_printf ("NVDEC H.265 Stateless Decoder with device %d",
+        cdata->cuda_device_id);
+  }
+
+  gst_element_class_set_metadata (element_class, long_name,
+      "Codec/Decoder/Video/Hardware",
+      "Nvidia H.265 video decoder", "Seungha Yang <seungha@centricular.com>");
+  g_free (long_name);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
+          cdata->sink_caps));
+  gst_element_class_add_pad_template (element_class,
+      gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
+          cdata->src_caps));
+
+  nvdec_class->cuda_device_id = cdata->cuda_device_id;
+
+  gst_caps_unref (cdata->sink_caps);
+  gst_caps_unref (cdata->src_caps);
+  g_free (cdata);
+}
+
+void
+gst_nv_h265_dec_register (GstPlugin * plugin, guint device_id, guint rank,
+    GstCaps * sink_caps, GstCaps * src_caps, gboolean is_primary)
+{
+  GTypeQuery type_query;
+  GTypeInfo type_info = { 0, };
+  GType subtype;
+  gchar *type_name;
+  gchar *feature_name;
+  GstNvH265DecClassData *cdata;
+  gboolean is_default = TRUE;
+  GValue value_list = G_VALUE_INIT;
+  GValue value = G_VALUE_INIT;
+
+  cdata = g_new0 (GstNvH265DecClassData, 1);
+  cdata->sink_caps = gst_caps_copy (sink_caps);
+
+  /* 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;
+
+  g_type_query (GST_TYPE_NV_H265_DEC, &type_query);
+  memset (&type_info, 0, sizeof (type_info));
+  type_info.class_size = type_query.class_size;
+  type_info.instance_size = type_query.instance_size;
+  type_info.class_init = (GClassInitFunc) gst_nv_h265_dec_subclass_init;
+  type_info.class_data = cdata;
+
+  if (is_primary) {
+    type_name = g_strdup ("GstNvH265StatelessPrimaryDec");
+    feature_name = g_strdup ("nvh265dec");
+  } else {
+    type_name = g_strdup ("GstNvH265StatelessDec");
+    feature_name = g_strdup ("nvh265sldec");
+  }
+
+  if (g_type_from_name (type_name) != 0) {
+    g_free (type_name);
+    g_free (feature_name);
+    if (is_primary) {
+      type_name =
+          g_strdup_printf ("GstNvH265StatelessPrimaryDevice%dDec", device_id);
+      feature_name = g_strdup_printf ("nvh265device%ddec", device_id);
+    } else {
+      type_name = g_strdup_printf ("GstNvH265StatelessDevice%dDec", device_id);
+      feature_name = g_strdup_printf ("nvh265sldevice%ddec", device_id);
+    }
+
+    is_default = FALSE;
+  }
+
+  cdata->is_default = is_default;
+  subtype = g_type_register_static (GST_TYPE_NV_H265_DEC,
+      type_name, &type_info, 0);
+
+  /* make lower rank than default device */
+  if (rank > 0 && !is_default)
+    rank--;
+
+  if (!gst_element_register (plugin, feature_name, rank, subtype))
+    GST_WARNING ("Failed to register plugin '%s'", type_name);
+
+  g_free (type_name);
+  g_free (feature_name);
+}
diff --git a/sys/nvcodec/gstnvh265dec.h b/sys/nvcodec/gstnvh265dec.h
new file mode 100644
index 000000000..3cc0041ec
--- /dev/null
+++ b/sys/nvcodec/gstnvh265dec.h
@@ -0,0 +1,49 @@
+/* GStreamer
+ * Copyright (C) 2020 Seungha Yang <seungha@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_NV_H265_DEC_H__
+#define __GST_NV_H265_DEC_H__
+
+#include <gst/gst.h>
+#include <gst/codecs/gsth265decoder.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_NV_H265_DEC            (gst_nv_h265_dec_get_type())
+#define GST_NV_H265_DEC(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj), GST_TYPE_NV_H265_DEC, GstNvH265Dec))
+#define GST_NV_H265_DEC_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),  GST_TYPE_NV_H265_DEC, GstNvH265DecClass))
+#define GST_NV_H265_DEC_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj),  GST_TYPE_NV_H265_DEC, GstNvH265DecClass))
+
+typedef struct _GstNvH265Dec GstNvH265Dec;
+typedef struct _GstNvH265DecClass GstNvH265DecClass;
+
+G_GNUC_INTERNAL
+GType gst_nv_h265_dec_get_type (void);
+
+G_GNUC_INTERNAL
+void gst_nv_h265_dec_register (GstPlugin * plugin,
+                               guint device_id,
+                               guint rank,
+                               GstCaps * sink_caps,
+                               GstCaps * src_caps,
+                               gboolean is_primary);
+
+G_END_DECLS
+
+#endif /* __GST_NV_H265_DEC_H__ */
diff --git a/sys/nvcodec/meson.build b/sys/nvcodec/meson.build
index 5a75e8129..bc153b360 100644
--- a/sys/nvcodec/meson.build
+++ b/sys/nvcodec/meson.build
@@ -11,6 +11,7 @@ nvcodec_sources = [
   'gstcudautils.c',
   'gstnvdecoder.c',
   'gstnvh264dec.c',
+  'gstnvh265dec.c',
 ]
 
 if get_option('nvcodec').disabled()
diff --git a/sys/nvcodec/plugin.c b/sys/nvcodec/plugin.c
index e35031431..1ee6f9398 100644
--- a/sys/nvcodec/plugin.c
+++ b/sys/nvcodec/plugin.c
@@ -32,6 +32,7 @@
 #include "gstnvdec.h"
 #include "gstnvenc.h"
 #include "gstnvh264dec.h"
+#include "gstnvh265dec.h"
 #include "gstnvdecoder.h"
 
 GST_DEBUG_CATEGORY (gst_nvcodec_debug);
@@ -54,6 +55,7 @@ plugin_init (GstPlugin * plugin)
   guint api_minor_ver = 1;
   const gchar *env;
   gboolean use_h264_sl_dec = FALSE;
+  gboolean use_h265_sl_dec = FALSE;
 
   GST_DEBUG_CATEGORY_INIT (gst_nvcodec_debug, "nvcodec", 0, "nvcodec");
   GST_DEBUG_CATEGORY_INIT (gst_nvdec_debug, "nvdec", 0, "nvdec");
@@ -103,9 +105,10 @@ plugin_init (GstPlugin * plugin)
       if (g_ascii_strcasecmp (*iter, "h264") == 0) {
         GST_INFO ("Found %s in GST_USE_NV_STATELESS_CODEC environment", *iter);
         use_h264_sl_dec = TRUE;
-        break;
+      } else if (g_ascii_strcasecmp (*iter, "h265") == 0) {
+        GST_INFO ("Found %s in GST_USE_NV_STATELESS_CODEC environment", *iter);
+        use_h265_sl_dec = TRUE;
       }
-
     }
 
     g_strfreev (split);
@@ -147,16 +150,31 @@ plugin_init (GstPlugin * plugin)
               "src template %" GST_PTR_FORMAT, codec_name,
               sink_template, src_template);
 
-          if (codec == cudaVideoCodec_H264) {
-            gst_nv_h264_dec_register (plugin,
-                i, GST_RANK_SECONDARY, sink_template, src_template, FALSE);
-            if (use_h264_sl_dec) {
-              GST_INFO ("Skip register cuvid parser based nvh264dec");
-              register_cuviddec = FALSE;
-
+          switch (codec) {
+            case cudaVideoCodec_H264:
               gst_nv_h264_dec_register (plugin,
-                  i, GST_RANK_PRIMARY, sink_template, src_template, TRUE);
-            }
+                  i, GST_RANK_SECONDARY, sink_template, src_template, FALSE);
+              if (use_h264_sl_dec) {
+                GST_INFO ("Skip register cuvid parser based nvh264dec");
+                register_cuviddec = FALSE;
+
+                gst_nv_h264_dec_register (plugin,
+                    i, GST_RANK_PRIMARY, sink_template, src_template, TRUE);
+              }
+              break;
+            case cudaVideoCodec_HEVC:
+              gst_nv_h265_dec_register (plugin,
+                  i, GST_RANK_SECONDARY, sink_template, src_template, FALSE);
+              if (use_h265_sl_dec) {
+                GST_INFO ("Skip register cuvid parser based nvh264dec");
+                register_cuviddec = FALSE;
+
+                gst_nv_h265_dec_register (plugin,
+                    i, GST_RANK_PRIMARY, sink_template, src_template, TRUE);
+              }
+              break;
+            default:
+              break;
           }
 
           if (register_cuviddec) {