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/*
* 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 "golomb.h"
#include "evc.h"
#include "evc_parse.h"
// @see ISO_IEC_23094-1 (7.3.2.6 Slice layer RBSP syntax)
int ff_evc_parse_slice_header(GetBitContext *gb, EVCParserSliceHeader *sh,
const EVCParamSets *ps, enum EVCNALUnitType nalu_type)
{
const EVCParserPPS *pps;
const EVCParserSPS *sps;
int num_tiles_in_slice = 0;
unsigned slice_pic_parameter_set_id;
slice_pic_parameter_set_id = get_ue_golomb_31(gb);
if (slice_pic_parameter_set_id >= EVC_MAX_PPS_COUNT)
return AVERROR_INVALIDDATA;
pps = ps->pps[slice_pic_parameter_set_id];
if(!pps)
return AVERROR_INVALIDDATA;
sps = ps->sps[pps->pps_seq_parameter_set_id];
if(!sps)
return AVERROR_INVALIDDATA;
memset(sh, 0, sizeof(*sh));
sh->slice_pic_parameter_set_id = slice_pic_parameter_set_id;
if (!pps->single_tile_in_pic_flag) {
sh->single_tile_in_slice_flag = get_bits1(gb);
sh->first_tile_id = get_bits(gb, pps->tile_id_len_minus1 + 1);
} else
sh->single_tile_in_slice_flag = 1;
if (!sh->single_tile_in_slice_flag) {
if (pps->arbitrary_slice_present_flag)
sh->arbitrary_slice_flag = get_bits1(gb);
if (!sh->arbitrary_slice_flag)
sh->last_tile_id = get_bits(gb, pps->tile_id_len_minus1 + 1);
else {
sh->num_remaining_tiles_in_slice_minus1 = get_ue_golomb_long(gb);
num_tiles_in_slice = sh->num_remaining_tiles_in_slice_minus1 + 2;
for (int i = 0; i < num_tiles_in_slice - 1; ++i)
sh->delta_tile_id_minus1[i] = get_ue_golomb_long(gb);
}
}
sh->slice_type = get_ue_golomb_31(gb);
if (nalu_type == EVC_IDR_NUT)
sh->no_output_of_prior_pics_flag = get_bits1(gb);
if (sps->sps_mmvd_flag && ((sh->slice_type == EVC_SLICE_TYPE_B) || (sh->slice_type == EVC_SLICE_TYPE_P)))
sh->mmvd_group_enable_flag = get_bits1(gb);
else
sh->mmvd_group_enable_flag = 0;
if (sps->sps_alf_flag) {
int ChromaArrayType = sps->chroma_format_idc;
sh->slice_alf_enabled_flag = get_bits1(gb);
if (sh->slice_alf_enabled_flag) {
sh->slice_alf_luma_aps_id = get_bits(gb, 5);
sh->slice_alf_map_flag = get_bits1(gb);
sh->slice_alf_chroma_idc = get_bits(gb, 2);
if ((ChromaArrayType == 1 || ChromaArrayType == 2) && sh->slice_alf_chroma_idc > 0)
sh->slice_alf_chroma_aps_id = get_bits(gb, 5);
}
if (ChromaArrayType == 3) {
int sliceChromaAlfEnabledFlag = 0;
int sliceChroma2AlfEnabledFlag = 0;
if (sh->slice_alf_chroma_idc == 1) { // @see ISO_IEC_23094-1 (7.4.5)
sliceChromaAlfEnabledFlag = 1;
sliceChroma2AlfEnabledFlag = 0;
} else if (sh->slice_alf_chroma_idc == 2) {
sliceChromaAlfEnabledFlag = 0;
sliceChroma2AlfEnabledFlag = 1;
} else if (sh->slice_alf_chroma_idc == 3) {
sliceChromaAlfEnabledFlag = 1;
sliceChroma2AlfEnabledFlag = 1;
} else {
sliceChromaAlfEnabledFlag = 0;
sliceChroma2AlfEnabledFlag = 0;
}
if (!sh->slice_alf_enabled_flag)
sh->slice_alf_chroma_idc = get_bits(gb, 2);
if (sliceChromaAlfEnabledFlag) {
sh->slice_alf_chroma_aps_id = get_bits(gb, 5);
sh->slice_alf_chroma_map_flag = get_bits1(gb);
}
if (sliceChroma2AlfEnabledFlag) {
sh->slice_alf_chroma2_aps_id = get_bits(gb, 5);
sh->slice_alf_chroma2_map_flag = get_bits1(gb);
}
}
}
if (nalu_type != EVC_IDR_NUT) {
if (sps->sps_pocs_flag)
sh->slice_pic_order_cnt_lsb = get_bits(gb, sps->log2_max_pic_order_cnt_lsb_minus4 + 4);
}
// @note
// If necessary, add the missing fields to the EVCParserSliceHeader structure
// and then extend parser implementation
return 0;
}
int ff_evc_derive_poc(const EVCParamSets *ps, const EVCParserSliceHeader *sh,
EVCParserPoc *poc, enum EVCNALUnitType nalu_type, int tid)
{
const EVCParserPPS *pps = ps->pps[sh->slice_pic_parameter_set_id];
const EVCParserSPS *sps;
if (!pps)
return AVERROR_INVALIDDATA;
sps = ps->sps[pps->pps_seq_parameter_set_id];
if (!sps)
return AVERROR_INVALIDDATA;
if (sps->sps_pocs_flag) {
int PicOrderCntMsb = 0;
poc->prevPicOrderCntVal = poc->PicOrderCntVal;
if (nalu_type == EVC_IDR_NUT)
PicOrderCntMsb = 0;
else {
int MaxPicOrderCntLsb = 1 << (sps->log2_max_pic_order_cnt_lsb_minus4 + 4);
int prevPicOrderCntLsb = poc->PicOrderCntVal & (MaxPicOrderCntLsb - 1);
int prevPicOrderCntMsb = poc->PicOrderCntVal - prevPicOrderCntLsb;
if ((sh->slice_pic_order_cnt_lsb < prevPicOrderCntLsb) &&
((prevPicOrderCntLsb - sh->slice_pic_order_cnt_lsb) >= (MaxPicOrderCntLsb / 2)))
PicOrderCntMsb = prevPicOrderCntMsb + MaxPicOrderCntLsb;
else if ((sh->slice_pic_order_cnt_lsb > prevPicOrderCntLsb) &&
((sh->slice_pic_order_cnt_lsb - prevPicOrderCntLsb) > (MaxPicOrderCntLsb / 2)))
PicOrderCntMsb = prevPicOrderCntMsb - MaxPicOrderCntLsb;
else
PicOrderCntMsb = prevPicOrderCntMsb;
}
poc->PicOrderCntVal = PicOrderCntMsb + sh->slice_pic_order_cnt_lsb;
} else {
if (nalu_type == EVC_IDR_NUT) {
poc->PicOrderCntVal = 0;
poc->DocOffset = -1;
} else {
int SubGopLength = (int)pow(2.0, sps->log2_sub_gop_length);
if (tid == 0) {
poc->PicOrderCntVal = poc->prevPicOrderCntVal + SubGopLength;
poc->DocOffset = 0;
poc->prevPicOrderCntVal = poc->PicOrderCntVal;
} else {
int ExpectedTemporalId;
int PocOffset;
int prevDocOffset = poc->DocOffset;
poc->DocOffset = (prevDocOffset + 1) % SubGopLength;
if (poc->DocOffset == 0) {
poc->prevPicOrderCntVal += SubGopLength;
ExpectedTemporalId = 0;
} else
ExpectedTemporalId = 1 + (int)log2(poc->DocOffset);
while (tid != ExpectedTemporalId) {
poc->DocOffset = (poc->DocOffset + 1) % SubGopLength;
if (poc->DocOffset == 0)
ExpectedTemporalId = 0;
else
ExpectedTemporalId = 1 + (int)log2(poc->DocOffset);
}
PocOffset = (int)(SubGopLength * ((2.0 * poc->DocOffset + 1) / (int)pow(2.0, tid) - 2));
poc->PicOrderCntVal = poc->prevPicOrderCntVal + PocOffset;
}
}
}
return 0;
}
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