/*
  * MPEG-4 Part 10 / AVC / H.264 HW decode acceleration through NVDEC
  *
  * Copyright (c) 2016 Anton Khirnov
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */
 
 #include <stdint.h>
 #include <string.h>
 
 #include "avcodec.h"
 #include "nvdec.h"
 #include "decode.h"
 #include "internal.h"
 #include "h264dec.h"
 
 static void dpb_add(const H264Context *h, CUVIDH264DPBENTRY *dst, const H264Picture *src,
                     int frame_idx)
 {
     FrameDecodeData *fdd = (FrameDecodeData*)src->f->private_ref->data;
     const NVDECFrame *cf = fdd->hwaccel_priv;
 
     dst->PicIdx             = cf ? cf->idx : -1;
     dst->FrameIdx           = frame_idx;
     dst->is_long_term       = src->long_ref;
     dst->not_existing       = 0;
     dst->used_for_reference = src->reference & 3;
     dst->FieldOrderCnt[0]   = src->field_poc[0];
     dst->FieldOrderCnt[1]   = src->field_poc[1];
 }
 
 static int nvdec_h264_start_frame(AVCodecContext *avctx,
                                   const uint8_t *buffer, uint32_t size)
 {
     const H264Context *h = avctx->priv_data;
     const PPS *pps = h->ps.pps;
     const SPS *sps = h->ps.sps;
 
     NVDECContext       *ctx = avctx->internal->hwaccel_priv_data;
     CUVIDPICPARAMS      *pp = &ctx->pic_params;
     CUVIDH264PICPARAMS *ppc = &pp->CodecSpecific.h264;
     FrameDecodeData *fdd;
     NVDECFrame *cf;
 
     int i, dpb_size, ret;
 
     ret = ff_nvdec_start_frame(avctx, h->cur_pic_ptr->f);
     if (ret < 0)
         return ret;
 
     fdd = (FrameDecodeData*)h->cur_pic_ptr->f->private_ref->data;
     cf  = (NVDECFrame*)fdd->hwaccel_priv;
 
     *pp = (CUVIDPICPARAMS) {
         .PicWidthInMbs     = h->mb_width,
         .FrameHeightInMbs  = h->mb_height,
         .CurrPicIdx        = cf->idx,
         .field_pic_flag    = FIELD_PICTURE(h),
         .bottom_field_flag = h->picture_structure == PICT_BOTTOM_FIELD,
         .second_field      = FIELD_PICTURE(h) && !h->first_field,
         .ref_pic_flag      = h->nal_ref_idc != 0,
         .intra_pic_flag    = 0,
 
         .CodecSpecific.h264 = {
             .log2_max_frame_num_minus4            = sps->log2_max_frame_num - 4,
             .pic_order_cnt_type                   = sps->poc_type,
             .log2_max_pic_order_cnt_lsb_minus4    = FFMAX(sps->log2_max_poc_lsb - 4, 0),
             .delta_pic_order_always_zero_flag     = sps->delta_pic_order_always_zero_flag,
             .frame_mbs_only_flag                  = sps->frame_mbs_only_flag,
             .direct_8x8_inference_flag            = sps->direct_8x8_inference_flag,
             .num_ref_frames                       = sps->ref_frame_count,
             .residual_colour_transform_flag       = sps->residual_color_transform_flag,
             .bit_depth_luma_minus8                = sps->bit_depth_luma - 8,
             .bit_depth_chroma_minus8              = sps->bit_depth_chroma - 8,
             .qpprime_y_zero_transform_bypass_flag = sps->transform_bypass,
 
             .entropy_coding_mode_flag               = pps->cabac,
             .pic_order_present_flag                 = pps->pic_order_present,
             .num_ref_idx_l0_active_minus1           = pps->ref_count[0] - 1,
             .num_ref_idx_l1_active_minus1           = pps->ref_count[1] - 1,
             .weighted_pred_flag                     = pps->weighted_pred,
             .weighted_bipred_idc                    = pps->weighted_bipred_idc,
             .pic_init_qp_minus26                    = pps->init_qp - 26,
             .deblocking_filter_control_present_flag = pps->deblocking_filter_parameters_present,
             .redundant_pic_cnt_present_flag         = pps->redundant_pic_cnt_present,
             .transform_8x8_mode_flag                = pps->transform_8x8_mode,
             .MbaffFrameFlag                         = sps->mb_aff && !FIELD_PICTURE(h),
             .constrained_intra_pred_flag            = pps->constrained_intra_pred,
             .chroma_qp_index_offset                 = pps->chroma_qp_index_offset[0],
             .second_chroma_qp_index_offset          = pps->chroma_qp_index_offset[1],
             .ref_pic_flag                           = h->nal_ref_idc != 0,
             .frame_num                              = h->poc.frame_num,
             .CurrFieldOrderCnt[0]                   = h->cur_pic_ptr->field_poc[0],
             .CurrFieldOrderCnt[1]                   = h->cur_pic_ptr->field_poc[1],
         },
     };
 
     memcpy(ppc->WeightScale4x4,    pps->scaling_matrix4,    sizeof(ppc->WeightScale4x4));
     memcpy(ppc->WeightScale8x8[0], pps->scaling_matrix8[0], sizeof(ppc->WeightScale8x8[0]));
     memcpy(ppc->WeightScale8x8[1], pps->scaling_matrix8[3], sizeof(ppc->WeightScale8x8[0]));
 
     dpb_size = 0;
     for (i = 0; i < h->short_ref_count; i++)
         dpb_add(h, &ppc->dpb[dpb_size++], h->short_ref[i], h->short_ref[i]->frame_num);
     for (i = 0; i < 16; i++) {
         if (h->long_ref[i])
             dpb_add(h, &ppc->dpb[dpb_size++], h->long_ref[i], i);
     }
 
     for (i = dpb_size; i < FF_ARRAY_ELEMS(ppc->dpb); i++)
         ppc->dpb[i].PicIdx = -1;
 
     return 0;
 }
 
 static int nvdec_h264_decode_slice(AVCodecContext *avctx, const uint8_t *buffer,
                                    uint32_t size)
 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
     void *tmp;
 
     tmp = av_fast_realloc(ctx->bitstream, &ctx->bitstream_allocated,
                           ctx->bitstream_len + size + 3);
     if (!tmp)
         return AVERROR(ENOMEM);
     ctx->bitstream = tmp;
 
     tmp = av_fast_realloc(ctx->slice_offsets, &ctx->slice_offsets_allocated,
                           (ctx->nb_slices + 1) * sizeof(*ctx->slice_offsets));
     if (!tmp)
         return AVERROR(ENOMEM);
     ctx->slice_offsets = tmp;
 
     AV_WB24(ctx->bitstream + ctx->bitstream_len, 1);
     memcpy(ctx->bitstream + ctx->bitstream_len + 3, buffer, size);
     ctx->slice_offsets[ctx->nb_slices] = ctx->bitstream_len ;
     ctx->bitstream_len += size + 3;
     ctx->nb_slices++;
 
     return 0;
 }
 

 static int nvdec_h264_frame_params(AVCodecContext *avctx,
                                    AVBufferRef *hw_frames_ctx)

 {
     const H264Context *h = avctx->priv_data;
     const SPS       *sps = h->ps.sps;

     return ff_nvdec_frame_params(avctx, hw_frames_ctx, sps->ref_frame_count + sps->num_reorder_frames);

 }
 

 const AVHWAccel ff_h264_nvdec_hwaccel = {

     .name                 = "h264_nvdec",
     .type                 = AVMEDIA_TYPE_VIDEO,
     .id                   = AV_CODEC_ID_H264,
     .pix_fmt              = AV_PIX_FMT_CUDA,
     .start_frame          = nvdec_h264_start_frame,
     .end_frame            = ff_nvdec_end_frame,
     .decode_slice         = nvdec_h264_decode_slice,

     .frame_params         = nvdec_h264_frame_params,
     .init                 = ff_nvdec_decode_init,

     .uninit               = ff_nvdec_decode_uninit,
     .priv_data_size       = sizeof(NVDECContext),
 };