func: int ff_h264_decode_seq_parameter_set(GetBitContext *gb, AVCodecContext *avctx,
  
                                       H264ParamSets *ps)
  
  {
  
      AVBufferRef *sps_buf;
  
      int profile_idc, level_idc, constraint_set_flags = 0;
  
      unsigned int sps_id;
  
      int i, log2_max_frame_num_minus4;
  
      SPS *sps;
  
  
  
      profile_idc           = get_bits(gb, 8);
  
      constraint_set_flags |= get_bits1(gb) << 0;   // constraint_set0_flag
  
      constraint_set_flags |= get_bits1(gb) << 1;   // constraint_set1_flag
  
      constraint_set_flags |= get_bits1(gb) << 2;   // constraint_set2_flag
  
      constraint_set_flags |= get_bits1(gb) << 3;   // constraint_set3_flag
  
      constraint_set_flags |= get_bits1(gb) << 4;   // constraint_set4_flag
  
      constraint_set_flags |= get_bits1(gb) << 5;   // constraint_set5_flag
  
      skip_bits(gb, 2);                             // reserved_zero_2bits
  
      level_idc = get_bits(gb, 8);
  
      sps_id    = get_ue_golomb_31(gb);
  
  
  
      if (sps_id >= MAX_SPS_COUNT) {
  
          av_log(avctx, AV_LOG_ERROR, "sps_id %u out of range\n", sps_id);
  
          return AVERROR_INVALIDDATA;
  
      }
  
  
  
      sps_buf = av_buffer_allocz(sizeof(*sps));
  
      if (!sps_buf)
  
          return AVERROR(ENOMEM);
  
      sps = (SPS*)sps_buf->data;
  
  
  
      sps->sps_id               = sps_id;
  
      sps->time_offset_length   = 24;
  
      sps->profile_idc          = profile_idc;
  
      sps->constraint_set_flags = constraint_set_flags;
  
      sps->level_idc            = level_idc;
  
  
  
      memset(sps->scaling_matrix4, 16, sizeof(sps->scaling_matrix4));
  
      memset(sps->scaling_matrix8, 16, sizeof(sps->scaling_matrix8));
  
      sps->scaling_matrix_present = 0;
  
  
  
      if (sps->profile_idc == 100 ||  // High profile
  
          sps->profile_idc == 110 ||  // High10 profile
  
          sps->profile_idc == 122 ||  // High422 profile
  
          sps->profile_idc == 244 ||  // High444 Predictive profile
  
          sps->profile_idc ==  44 ||  // Cavlc444 profile
  
          sps->profile_idc ==  83 ||  // Scalable Constrained High profile (SVC)
  
          sps->profile_idc ==  86 ||  // Scalable High Intra profile (SVC)
  
          sps->profile_idc == 118 ||  // Stereo High profile (MVC)
  
          sps->profile_idc == 128 ||  // Multiview High profile (MVC)
  
          sps->profile_idc == 138 ||  // Multiview Depth High profile (MVCD)
  
          sps->profile_idc == 144) {  // old High444 profile
  
          sps->chroma_format_idc = get_ue_golomb_31(gb);
  
          if (sps->chroma_format_idc > 3) {
  
              avpriv_request_sample(avctx, "chroma_format_idc %u",
  
                                    sps->chroma_format_idc);
  
              goto fail;
  
          } else if (sps->chroma_format_idc == 3) {
  
              sps->residual_color_transform_flag = get_bits1(gb);
  
          }
  
          sps->bit_depth_luma   = get_ue_golomb(gb) + 8;
  
          sps->bit_depth_chroma = get_ue_golomb(gb) + 8;
  
          if (sps->bit_depth_chroma != sps->bit_depth_luma) {
  
              avpriv_request_sample(avctx,
  
                                    "Different chroma and luma bit depth");
  
              goto fail;
  
          }
  
          sps->transform_bypass = get_bits1(gb);
  
          decode_scaling_matrices(gb, sps, NULL, 1,
  
                                  sps->scaling_matrix4, sps->scaling_matrix8);
  
      } else {
  
          sps->chroma_format_idc = 1;
  
          sps->bit_depth_luma    = 8;
  
          sps->bit_depth_chroma  = 8;
  
      }
  
  
  
      log2_max_frame_num_minus4 = get_ue_golomb(gb);
  
      if (log2_max_frame_num_minus4 < MIN_LOG2_MAX_FRAME_NUM - 4 ||
  
          log2_max_frame_num_minus4 > MAX_LOG2_MAX_FRAME_NUM - 4) {
  
          av_log(avctx, AV_LOG_ERROR,
  
                 "log2_max_frame_num_minus4 out of range (0-12): %d\n",
  
                 log2_max_frame_num_minus4);
  
          goto fail;
  
      }
  
      sps->log2_max_frame_num = log2_max_frame_num_minus4 + 4;
  
  
  
      sps->poc_type = get_ue_golomb_31(gb);
  
  
  
      if (sps->poc_type == 0) { // FIXME #define
  
          sps->log2_max_poc_lsb = get_ue_golomb(gb) + 4;
  
      } else if (sps->poc_type == 1) { // FIXME #define
  
          sps->delta_pic_order_always_zero_flag = get_bits1(gb);
  
          sps->offset_for_non_ref_pic           = get_se_golomb(gb);
  
          sps->offset_for_top_to_bottom_field   = get_se_golomb(gb);
  
          sps->poc_cycle_length                 = get_ue_golomb(gb);
  
  
  
          if ((unsigned)sps->poc_cycle_length >=
  
              FF_ARRAY_ELEMS(sps->offset_for_ref_frame)) {
  
              av_log(avctx, AV_LOG_ERROR,
  
                     "poc_cycle_length overflow %d\n", sps->poc_cycle_length);
  
              goto fail;
  
          }
  
  
  
          for (i = 0; i < sps->poc_cycle_length; i++)
  
              sps->offset_for_ref_frame[i] = get_se_golomb(gb);
  
      } else if (sps->poc_type != 2) {
  
          av_log(avctx, AV_LOG_ERROR, "illegal POC type %d\n", sps->poc_type);
  
          goto fail;
  
      }
  
  
  
      sps->ref_frame_count = get_ue_golomb_31(gb);
  
      if (sps->ref_frame_count > H264_MAX_PICTURE_COUNT - 2 ||
  
          sps->ref_frame_count >= 32U) {
  
          av_log(avctx, AV_LOG_ERROR,
  
                 "too many reference frames %d\n", sps->ref_frame_count);
  
          goto fail;
  
      }
  
      sps->gaps_in_frame_num_allowed_flag = get_bits1(gb);
  
      sps->mb_width                       = get_ue_golomb(gb) + 1;
  
      sps->mb_height                      = get_ue_golomb(gb) + 1;
  
      if ((unsigned)sps->mb_width  >= INT_MAX / 16 ||
  
          (unsigned)sps->mb_height >= INT_MAX / 16 ||
  
          av_image_check_size(16 * sps->mb_width,
  
                              16 * sps->mb_height, 0, avctx)) {
  
          av_log(avctx, AV_LOG_ERROR, "mb_width/height overflow\n");
  
          goto fail;
  
      }
  
  
  
      sps->frame_mbs_only_flag = get_bits1(gb);
  
      if (!sps->frame_mbs_only_flag)
  
          sps->mb_aff = get_bits1(gb);
  
      else
  
          sps->mb_aff = 0;
  
  
  
      sps->direct_8x8_inference_flag = get_bits1(gb);
  
      if (!sps->frame_mbs_only_flag && !sps->direct_8x8_inference_flag) {
  
          av_log(avctx, AV_LOG_ERROR,
  
                 "This stream was generated by a broken encoder, invalid 8x8 inference\n");
  
          goto fail;
  
      }
  
  
  
  #ifndef ALLOW_INTERLACE
  
      if (sps->mb_aff)
  
          av_log(avctx, AV_LOG_ERROR,
  
                 "MBAFF support not included; enable it at compile-time.\n");
  
  #endif
  
      sps->crop = get_bits1(gb);
  
      if (sps->crop) {
  
          unsigned int crop_left   = get_ue_golomb(gb);
  
          unsigned int crop_right  = get_ue_golomb(gb);
  
          unsigned int crop_top    = get_ue_golomb(gb);
  
          unsigned int crop_bottom = get_ue_golomb(gb);
  
  
  
          if (avctx->flags2 & AV_CODEC_FLAG2_IGNORE_CROP) {
  
              av_log(avctx, AV_LOG_DEBUG, "discarding sps cropping, original "
  
                                             "values are l:%d r:%d t:%d b:%d\n",
  
                     crop_left, crop_right, crop_top, crop_bottom);
  
  
  
              sps->crop_left   =
  
              sps->crop_right  =
  
              sps->crop_top    =
  
              sps->crop_bottom = 0;
  
          } else {
  
              int vsub   = (sps->chroma_format_idc == 1) ? 1 : 0;
  
              int hsub   = (sps->chroma_format_idc == 1 ||
  
                            sps->chroma_format_idc == 2) ? 1 : 0;
  
              int step_x = 1 << hsub;
  
              int step_y = (2 - sps->frame_mbs_only_flag) << vsub;
  
  
  
              if (crop_left & (0x1F >> (sps->bit_depth_luma > 8)) &&
  
                  !(avctx->flags & AV_CODEC_FLAG_UNALIGNED)) {
  
                  crop_left &= ~(0x1F >> (sps->bit_depth_luma > 8));
  
                  av_log(avctx, AV_LOG_WARNING,
  
                         "Reducing left cropping to %d "
  
                         "chroma samples to preserve alignment.\n",
  
                         crop_left);
  
              }
  
  
  
              if (INT_MAX / step_x             <= crop_left               ||
  
                  INT_MAX / step_x - crop_left <= crop_right              ||
  
                  16 * sps->mb_width <= step_x * (crop_left + crop_right) ||
  
                  INT_MAX / step_y             <= crop_top                ||
  
                  INT_MAX / step_y - crop_top  <= crop_bottom             ||
  
                  16 * sps->mb_height <= step_y * (crop_top + crop_bottom)) {
  
                  av_log(avctx, AV_LOG_WARNING, "Invalid crop parameters\n");
  
                  if (avctx->err_recognition & AV_EF_EXPLODE)
  
                      goto fail;
  
                  crop_left = crop_right = crop_top = crop_bottom = 0;
  
              }
  
  
  
              sps->crop_left   = crop_left   * step_x;
  
              sps->crop_right  = crop_right  * step_x;
  
              sps->crop_top    = crop_top    * step_y;
  
              sps->crop_bottom = crop_bottom * step_y;
  
          }
  
      } else {
  
          sps->crop_left   =
  
          sps->crop_right  =
  
          sps->crop_top    =
  
          sps->crop_bottom =
  
          sps->crop        = 0;
  
      }
  
  
  
      sps->vui_parameters_present_flag = get_bits1(gb);
  
      if (sps->vui_parameters_present_flag) {
  
          int ret = decode_vui_parameters(gb, avctx, sps);
  
          if (ret < 0 && avctx->err_recognition & AV_EF_EXPLODE)
  
              goto fail;
  
      }
  
  
  
      /* if the maximum delay is not stored in the SPS, derive it based on the
  
       * level */
  
      if (!sps->bitstream_restriction_flag &&
  
          (sps->ref_frame_count || avctx->strict_std_compliance >= FF_COMPLIANCE_STRICT)) {
  
          sps->num_reorder_frames = MAX_DELAYED_PIC_COUNT - 1;
  
          for (i = 0; i < FF_ARRAY_ELEMS(level_max_dpb_mbs); i++) {
  
              if (level_max_dpb_mbs[i][0] == sps->level_idc) {
  
                  sps->num_reorder_frames = FFMIN(level_max_dpb_mbs[i][1] / (sps->mb_width * sps->mb_height),
  
                                                  sps->num_reorder_frames);
  
                  break;
  
              }
  
          }
  
      }
  
  
  
      if (!sps->sar.den)
  
          sps->sar.den = 1;
  
  
  
      if (avctx->debug & FF_DEBUG_PICT_INFO) {
  
          static const char csp[4][5] = { "Gray", "420", "422", "444" };
  
          av_log(avctx, AV_LOG_DEBUG,
  
                 "sps:%u profile:%d/%d poc:%d ref:%d %dx%d %s %s crop:%u/%u/%u/%u %s %s %"PRId32"/%"PRId32"\n",
  
                 sps_id, sps->profile_idc, sps->level_idc,
  
                 sps->poc_type,
  
                 sps->ref_frame_count,
  
                 sps->mb_width, sps->mb_height,
  
                 sps->frame_mbs_only_flag ? "FRM" : (sps->mb_aff ? "MB-AFF" : "PIC-AFF"),
  
                 sps->direct_8x8_inference_flag ? "8B8" : "",
  
                 sps->crop_left, sps->crop_right,
  
                 sps->crop_top, sps->crop_bottom,
  
                 sps->vui_parameters_present_flag ? "VUI" : "",
  
                 csp[sps->chroma_format_idc],
  
                 sps->timing_info_present_flag ? sps->num_units_in_tick : 0,
  
                 sps->timing_info_present_flag ? sps->time_scale : 0);
  
      }
  
  
  
      /* check if this is a repeat of an already parsed SPS, then keep the
  
       * original one.
  
       * otherwise drop all PPSes that depend on it */
  
      if (ps->sps_list[sps_id] &&
  
          !memcmp(ps->sps_list[sps_id]->data, sps_buf->data, sps_buf->size)) {
  
          av_buffer_unref(&sps_buf);
  
      } else {
  
          remove_sps(ps, sps_id);
  
          ps->sps_list[sps_id] = sps_buf;
  
      }
  
  
  
      return 0;
  
  
  
  fail:
  
      av_buffer_unref(&sps_buf);
  
      return AVERROR_INVALIDDATA;
  
  }
  