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FFmpeg/libavcodec/evc_parse.c

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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 "parser.h"
#include "evc.h"
#include "evc_parse.h"
#define EXTENDED_SAR 255
#define NUM_CHROMA_FORMATS 4 // @see ISO_IEC_23094-1 section 6.2 table 2
static const enum AVPixelFormat pix_fmts_8bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY8, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P
};
static const enum AVPixelFormat pix_fmts_9bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY9, AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9
};
static const enum AVPixelFormat pix_fmts_10bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY10, AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10
};
static const enum AVPixelFormat pix_fmts_12bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY12, AV_PIX_FMT_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12
};
static const enum AVPixelFormat pix_fmts_14bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY14, AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14
};
static const enum AVPixelFormat pix_fmts_16bit[NUM_CHROMA_FORMATS] = {
AV_PIX_FMT_GRAY16, AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16
};
// nuh_temporal_id specifies a temporal identifier for the NAL unit
int ff_evc_get_temporal_id(const uint8_t *bits, int bits_size, void *logctx)
{
int temporal_id = 0;
uint16_t t = 0;
if (bits_size < EVC_NALU_HEADER_SIZE) {
av_log(logctx, AV_LOG_ERROR, "Can't read NAL unit header\n");
return 0;
}
// forbidden_zero_bit
if ((bits[0] & 0x80) != 0)
return -1;
t = AV_RB16(bits);
temporal_id = (t >> 6) & 0x0007;
return temporal_id;
}
// @see ISO_IEC_23094-1 (7.3.7 Reference picture list structure syntax)
static int ref_pic_list_struct(GetBitContext *gb, RefPicListStruct *rpl)
{
uint32_t delta_poc_st, strp_entry_sign_flag = 0;
rpl->ref_pic_num = get_ue_golomb(gb);
if (rpl->ref_pic_num > 0) {
delta_poc_st = get_ue_golomb(gb);
rpl->ref_pics[0] = delta_poc_st;
if (rpl->ref_pics[0] != 0) {
strp_entry_sign_flag = get_bits(gb, 1);
rpl->ref_pics[0] *= 1 - (strp_entry_sign_flag << 1);
}
}
for (int i = 1; i < rpl->ref_pic_num; ++i) {
delta_poc_st = get_ue_golomb(gb);
if (delta_poc_st != 0)
strp_entry_sign_flag = get_bits(gb, 1);
rpl->ref_pics[i] = rpl->ref_pics[i - 1] + delta_poc_st * (1 - (strp_entry_sign_flag << 1));
}
return 0;
}
// @see ISO_IEC_23094-1 (E.2.2 HRD parameters syntax)
static int hrd_parameters(GetBitContext *gb, HRDParameters *hrd)
{
hrd->cpb_cnt_minus1 = get_ue_golomb(gb);
hrd->bit_rate_scale = get_bits(gb, 4);
hrd->cpb_size_scale = get_bits(gb, 4);
for (int SchedSelIdx = 0; SchedSelIdx <= hrd->cpb_cnt_minus1; SchedSelIdx++) {
hrd->bit_rate_value_minus1[SchedSelIdx] = get_ue_golomb(gb);
hrd->cpb_size_value_minus1[SchedSelIdx] = get_ue_golomb(gb);
hrd->cbr_flag[SchedSelIdx] = get_bits(gb, 1);
}
hrd->initial_cpb_removal_delay_length_minus1 = get_bits(gb, 5);
hrd->cpb_removal_delay_length_minus1 = get_bits(gb, 5);
hrd->cpb_removal_delay_length_minus1 = get_bits(gb, 5);
hrd->time_offset_length = get_bits(gb, 5);
return 0;
}
// @see ISO_IEC_23094-1 (E.2.1 VUI parameters syntax)
static int vui_parameters(GetBitContext *gb, VUIParameters *vui)
{
vui->aspect_ratio_info_present_flag = get_bits(gb, 1);
if (vui->aspect_ratio_info_present_flag) {
vui->aspect_ratio_idc = get_bits(gb, 8);
if (vui->aspect_ratio_idc == EXTENDED_SAR) {
vui->sar_width = get_bits(gb, 16);
vui->sar_height = get_bits(gb, 16);
}
}
vui->overscan_info_present_flag = get_bits(gb, 1);
if (vui->overscan_info_present_flag)
vui->overscan_appropriate_flag = get_bits(gb, 1);
vui->video_signal_type_present_flag = get_bits(gb, 1);
if (vui->video_signal_type_present_flag) {
vui->video_format = get_bits(gb, 3);
vui->video_full_range_flag = get_bits(gb, 1);
vui->colour_description_present_flag = get_bits(gb, 1);
if (vui->colour_description_present_flag) {
vui->colour_primaries = get_bits(gb, 8);
vui->transfer_characteristics = get_bits(gb, 8);
vui->matrix_coefficients = get_bits(gb, 8);
}
}
vui->chroma_loc_info_present_flag = get_bits(gb, 1);
if (vui->chroma_loc_info_present_flag) {
vui->chroma_sample_loc_type_top_field = get_ue_golomb(gb);
vui->chroma_sample_loc_type_bottom_field = get_ue_golomb(gb);
}
vui->neutral_chroma_indication_flag = get_bits(gb, 1);
vui->field_seq_flag = get_bits(gb, 1);
vui->timing_info_present_flag = get_bits(gb, 1);
if (vui->timing_info_present_flag) {
vui->num_units_in_tick = get_bits(gb, 32);
vui->time_scale = get_bits(gb, 32);
vui->fixed_pic_rate_flag = get_bits(gb, 1);
}
vui->nal_hrd_parameters_present_flag = get_bits(gb, 1);
if (vui->nal_hrd_parameters_present_flag)
hrd_parameters(gb, &vui->hrd_parameters);
vui->vcl_hrd_parameters_present_flag = get_bits(gb, 1);
if (vui->vcl_hrd_parameters_present_flag)
hrd_parameters(gb, &vui->hrd_parameters);
if (vui->nal_hrd_parameters_present_flag || vui->vcl_hrd_parameters_present_flag)
vui->low_delay_hrd_flag = get_bits(gb, 1);
vui->pic_struct_present_flag = get_bits(gb, 1);
vui->bitstream_restriction_flag = get_bits(gb, 1);
if (vui->bitstream_restriction_flag) {
vui->motion_vectors_over_pic_boundaries_flag = get_bits(gb, 1);
vui->max_bytes_per_pic_denom = get_ue_golomb(gb);
vui->max_bits_per_mb_denom = get_ue_golomb(gb);
vui->log2_max_mv_length_horizontal = get_ue_golomb(gb);
vui->log2_max_mv_length_vertical = get_ue_golomb(gb);
vui->num_reorder_pics = get_ue_golomb(gb);
vui->max_dec_pic_buffering = get_ue_golomb(gb);
}
return 0;
}
// @see ISO_IEC_23094-1 (7.3.2.1 SPS RBSP syntax)
EVCParserSPS *ff_evc_parse_sps(EVCParserContext *ctx, const uint8_t *bs, int bs_size)
{
GetBitContext gb;
EVCParserSPS *sps;
int sps_seq_parameter_set_id;
if (init_get_bits8(&gb, bs, bs_size) < 0)
return NULL;
sps_seq_parameter_set_id = get_ue_golomb(&gb);
if (sps_seq_parameter_set_id >= EVC_MAX_SPS_COUNT)
return NULL;
if(!ctx->sps[sps_seq_parameter_set_id]) {
if((ctx->sps[sps_seq_parameter_set_id] = av_malloc(sizeof(EVCParserSPS))) == NULL)
return NULL;
}
sps = ctx->sps[sps_seq_parameter_set_id];
memset(sps, 0, sizeof(*sps));
sps->sps_seq_parameter_set_id = sps_seq_parameter_set_id;
// the Baseline profile is indicated by profile_idc eqal to 0
// the Main profile is indicated by profile_idc eqal to 1
sps->profile_idc = get_bits(&gb, 8);
sps->level_idc = get_bits(&gb, 8);
skip_bits_long(&gb, 32); /* skip toolset_idc_h */
skip_bits_long(&gb, 32); /* skip toolset_idc_l */
// 0 - monochrome
// 1 - 4:2:0
// 2 - 4:2:2
// 3 - 4:4:4
sps->chroma_format_idc = get_ue_golomb(&gb);
sps->pic_width_in_luma_samples = get_ue_golomb(&gb);
sps->pic_height_in_luma_samples = get_ue_golomb(&gb);
sps->bit_depth_luma_minus8 = get_ue_golomb(&gb);
sps->bit_depth_chroma_minus8 = get_ue_golomb(&gb);
sps->sps_btt_flag = get_bits(&gb, 1);
if (sps->sps_btt_flag) {
sps->log2_ctu_size_minus5 = get_ue_golomb(&gb);
sps->log2_min_cb_size_minus2 = get_ue_golomb(&gb);
sps->log2_diff_ctu_max_14_cb_size = get_ue_golomb(&gb);
sps->log2_diff_ctu_max_tt_cb_size = get_ue_golomb(&gb);
sps->log2_diff_min_cb_min_tt_cb_size_minus2 = get_ue_golomb(&gb);
}
sps->sps_suco_flag = get_bits(&gb, 1);
if (sps->sps_suco_flag) {
sps->log2_diff_ctu_size_max_suco_cb_size = get_ue_golomb(&gb);
sps->log2_diff_max_suco_min_suco_cb_size = get_ue_golomb(&gb);
}
sps->sps_admvp_flag = get_bits(&gb, 1);
if (sps->sps_admvp_flag) {
sps->sps_affine_flag = get_bits(&gb, 1);
sps->sps_amvr_flag = get_bits(&gb, 1);
sps->sps_dmvr_flag = get_bits(&gb, 1);
sps->sps_mmvd_flag = get_bits(&gb, 1);
sps->sps_hmvp_flag = get_bits(&gb, 1);
}
sps->sps_eipd_flag = get_bits(&gb, 1);
if (sps->sps_eipd_flag) {
sps->sps_ibc_flag = get_bits(&gb, 1);
if (sps->sps_ibc_flag)
sps->log2_max_ibc_cand_size_minus2 = get_ue_golomb(&gb);
}
sps->sps_cm_init_flag = get_bits(&gb, 1);
if (sps->sps_cm_init_flag)
sps->sps_adcc_flag = get_bits(&gb, 1);
sps->sps_iqt_flag = get_bits(&gb, 1);
if (sps->sps_iqt_flag)
sps->sps_ats_flag = get_bits(&gb, 1);
sps->sps_addb_flag = get_bits(&gb, 1);
sps->sps_alf_flag = get_bits(&gb, 1);
sps->sps_htdf_flag = get_bits(&gb, 1);
sps->sps_rpl_flag = get_bits(&gb, 1);
sps->sps_pocs_flag = get_bits(&gb, 1);
sps->sps_dquant_flag = get_bits(&gb, 1);
sps->sps_dra_flag = get_bits(&gb, 1);
if (sps->sps_pocs_flag)
sps->log2_max_pic_order_cnt_lsb_minus4 = get_ue_golomb(&gb);
if (!sps->sps_pocs_flag || !sps->sps_rpl_flag) {
sps->log2_sub_gop_length = get_ue_golomb(&gb);
if (sps->log2_sub_gop_length == 0)
sps->log2_ref_pic_gap_length = get_ue_golomb(&gb);
}
if (!sps->sps_rpl_flag)
sps->max_num_tid0_ref_pics = get_ue_golomb(&gb);
else {
sps->sps_max_dec_pic_buffering_minus1 = get_ue_golomb(&gb);
sps->long_term_ref_pic_flag = get_bits(&gb, 1);
sps->rpl1_same_as_rpl0_flag = get_bits(&gb, 1);
sps->num_ref_pic_list_in_sps[0] = get_ue_golomb(&gb);
for (int i = 0; i < sps->num_ref_pic_list_in_sps[0]; ++i)
ref_pic_list_struct(&gb, &sps->rpls[0][i]);
if (!sps->rpl1_same_as_rpl0_flag) {
sps->num_ref_pic_list_in_sps[1] = get_ue_golomb(&gb);
for (int i = 0; i < sps->num_ref_pic_list_in_sps[1]; ++i)
ref_pic_list_struct(&gb, &sps->rpls[1][i]);
}
}
sps->picture_cropping_flag = get_bits(&gb, 1);
if (sps->picture_cropping_flag) {
sps->picture_crop_left_offset = get_ue_golomb(&gb);
sps->picture_crop_right_offset = get_ue_golomb(&gb);
sps->picture_crop_top_offset = get_ue_golomb(&gb);
sps->picture_crop_bottom_offset = get_ue_golomb(&gb);
}
if (sps->chroma_format_idc != 0) {
sps->chroma_qp_table_struct.chroma_qp_table_present_flag = get_bits(&gb, 1);
if (sps->chroma_qp_table_struct.chroma_qp_table_present_flag) {
sps->chroma_qp_table_struct.same_qp_table_for_chroma = get_bits(&gb, 1);
sps->chroma_qp_table_struct.global_offset_flag = get_bits(&gb, 1);
for (int i = 0; i < (sps->chroma_qp_table_struct.same_qp_table_for_chroma ? 1 : 2); i++) {
sps->chroma_qp_table_struct.num_points_in_qp_table_minus1[i] = get_ue_golomb(&gb);;
for (int j = 0; j <= sps->chroma_qp_table_struct.num_points_in_qp_table_minus1[i]; j++) {
sps->chroma_qp_table_struct.delta_qp_in_val_minus1[i][j] = get_bits(&gb, 6);
sps->chroma_qp_table_struct.delta_qp_out_val[i][j] = get_se_golomb(&gb);
}
}
}
}
sps->vui_parameters_present_flag = get_bits(&gb, 1);
if (sps->vui_parameters_present_flag)
vui_parameters(&gb, &(sps->vui_parameters));
// @note
// If necessary, add the missing fields to the EVCParserSPS structure
// and then extend parser implementation
return sps;
}
// @see ISO_IEC_23094-1 (7.3.2.2 SPS RBSP syntax)
//
// @note
// The current implementation of parse_sps function doesn't handle VUI parameters parsing.
// If it will be needed, parse_sps function could be extended to handle VUI parameters parsing
// to initialize fields of the AVCodecContex i.e. color_primaries, color_trc,color_range
//
EVCParserPPS *ff_evc_parse_pps(EVCParserContext *ctx, const uint8_t *bs, int bs_size)
{
GetBitContext gb;
EVCParserPPS *pps;
int pps_pic_parameter_set_id;
if (init_get_bits8(&gb, bs, bs_size) < 0)
return NULL;
pps_pic_parameter_set_id = get_ue_golomb(&gb);
if (pps_pic_parameter_set_id > EVC_MAX_PPS_COUNT)
return NULL;
if(!ctx->pps[pps_pic_parameter_set_id]) {
if ((ctx->pps[pps_pic_parameter_set_id] = av_malloc(sizeof(EVCParserPPS))) == NULL)
return NULL;
}
pps = ctx->pps[pps_pic_parameter_set_id];
memset(pps, 0, sizeof(*pps));
pps->pps_pic_parameter_set_id = pps_pic_parameter_set_id;
pps->pps_seq_parameter_set_id = get_ue_golomb(&gb);
if (pps->pps_seq_parameter_set_id >= EVC_MAX_SPS_COUNT) {
av_freep(&ctx->pps[pps_pic_parameter_set_id]);
return NULL;
}
pps->num_ref_idx_default_active_minus1[0] = get_ue_golomb(&gb);
pps->num_ref_idx_default_active_minus1[1] = get_ue_golomb(&gb);
pps->additional_lt_poc_lsb_len = get_ue_golomb(&gb);
pps->rpl1_idx_present_flag = get_bits(&gb, 1);
pps->single_tile_in_pic_flag = get_bits(&gb, 1);
if (!pps->single_tile_in_pic_flag) {
pps->num_tile_columns_minus1 = get_ue_golomb(&gb);
pps->num_tile_rows_minus1 = get_ue_golomb(&gb);
pps->uniform_tile_spacing_flag = get_bits(&gb, 1);
if (!pps->uniform_tile_spacing_flag) {
for (int i = 0; i < pps->num_tile_columns_minus1; i++)
pps->tile_column_width_minus1[i] = get_ue_golomb(&gb);
for (int i = 0; i < pps->num_tile_rows_minus1; i++)
pps->tile_row_height_minus1[i] = get_ue_golomb(&gb);
}
pps->loop_filter_across_tiles_enabled_flag = get_bits(&gb, 1);
pps->tile_offset_len_minus1 = get_ue_golomb(&gb);
}
pps->tile_id_len_minus1 = get_ue_golomb(&gb);
pps->explicit_tile_id_flag = get_bits(&gb, 1);
if (pps->explicit_tile_id_flag) {
for (int i = 0; i <= pps->num_tile_rows_minus1; i++) {
for (int j = 0; j <= pps->num_tile_columns_minus1; j++)
pps->tile_id_val[i][j] = get_bits(&gb, pps->tile_id_len_minus1 + 1);
}
}
pps->pic_dra_enabled_flag = 0;
pps->pic_dra_enabled_flag = get_bits(&gb, 1);
if (pps->pic_dra_enabled_flag)
pps->pic_dra_aps_id = get_bits(&gb, 5);
pps->arbitrary_slice_present_flag = get_bits(&gb, 1);
pps->constrained_intra_pred_flag = get_bits(&gb, 1);
pps->cu_qp_delta_enabled_flag = get_bits(&gb, 1);
if (pps->cu_qp_delta_enabled_flag)
pps->log2_cu_qp_delta_area_minus6 = get_ue_golomb(&gb);
return pps;
}
// @see ISO_IEC_23094-1 (7.3.2.6 Slice layer RBSP syntax)
static int evc_parse_slice_header(EVCParserContext *ctx, EVCParserSliceHeader *sh, const uint8_t *bs, int bs_size)
{
GetBitContext gb;
EVCParserPPS *pps;
EVCParserSPS *sps;
int num_tiles_in_slice = 0;
int slice_pic_parameter_set_id;
int ret;
if ((ret = init_get_bits8(&gb, bs, bs_size)) < 0)
return ret;
slice_pic_parameter_set_id = get_ue_golomb(&gb);
if (slice_pic_parameter_set_id < 0 || slice_pic_parameter_set_id >= EVC_MAX_PPS_COUNT)
return AVERROR_INVALIDDATA;
pps = ctx->pps[slice_pic_parameter_set_id];
if(!pps)
return AVERROR_INVALIDDATA;
sps = ctx->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_bits(&gb, 1);
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_bits(&gb, 1);
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(&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(&gb);
}
}
sh->slice_type = get_ue_golomb(&gb);
if (ctx->nalu_type == EVC_IDR_NUT)
sh->no_output_of_prior_pics_flag = get_bits(&gb, 1);
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_bits(&gb, 1);
else
sh->mmvd_group_enable_flag = 0;
if (sps->sps_alf_flag) {
int ChromaArrayType = sps->chroma_format_idc;
sh->slice_alf_enabled_flag = get_bits(&gb, 1);
if (sh->slice_alf_enabled_flag) {
sh->slice_alf_luma_aps_id = get_bits(&gb, 5);
sh->slice_alf_map_flag = get_bits(&gb, 1);
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_bits(&gb, 1);
}
if (sliceChroma2AlfEnabledFlag) {
sh->slice_alf_chroma2_aps_id = get_bits(&gb, 5);
sh->slice_alf_chroma2_map_flag = get_bits(&gb, 1);
}
}
}
if (ctx->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_parse_nal_unit(EVCParserContext *ctx, const uint8_t *buf, int buf_size, void *logctx)
{
int nalu_type, nalu_size;
int tid;
const uint8_t *data = buf;
int data_size = buf_size;
// ctx->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
ctx->key_frame = -1;
nalu_size = buf_size;
if (nalu_size <= 0) {
av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit size: (%d)\n", nalu_size);
return AVERROR_INVALIDDATA;
}
// @see ISO_IEC_23094-1_2020, 7.4.2.2 NAL unit header semantic (Table 4 - NAL unit type codes and NAL unit type classes)
// @see enum EVCNALUnitType in evc.h
nalu_type = evc_get_nalu_type(data, data_size, logctx);
if (nalu_type < EVC_NOIDR_NUT || nalu_type > EVC_UNSPEC_NUT62) {
av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit type: (%d)\n", nalu_type);
return AVERROR_INVALIDDATA;
}
ctx->nalu_type = nalu_type;
tid = ff_evc_get_temporal_id(data, data_size, logctx);
if (tid < 0) {
av_log(logctx, AV_LOG_ERROR, "Invalid temporial id: (%d)\n", tid);
return AVERROR_INVALIDDATA;
}
ctx->nuh_temporal_id = tid;
data += EVC_NALU_HEADER_SIZE;
data_size -= EVC_NALU_HEADER_SIZE;
switch(nalu_type) {
case EVC_SPS_NUT: {
EVCParserSPS *sps;
int SubGopLength;
int bit_depth;
sps = ff_evc_parse_sps(ctx, data, nalu_size);
if (!sps) {
av_log(logctx, AV_LOG_ERROR, "SPS parsing error\n");
return AVERROR_INVALIDDATA;
}
ctx->coded_width = sps->pic_width_in_luma_samples;
ctx->coded_height = sps->pic_height_in_luma_samples;
if(sps->picture_cropping_flag) {
ctx->width = sps->pic_width_in_luma_samples - sps->picture_crop_left_offset - sps->picture_crop_right_offset;
ctx->height = sps->pic_height_in_luma_samples - sps->picture_crop_top_offset - sps->picture_crop_bottom_offset;
} else {
ctx->width = sps->pic_width_in_luma_samples;
ctx->height = sps->pic_height_in_luma_samples;
}
SubGopLength = (int)pow(2.0, sps->log2_sub_gop_length);
ctx->gop_size = SubGopLength;
ctx->delay = (sps->sps_max_dec_pic_buffering_minus1) ? sps->sps_max_dec_pic_buffering_minus1 - 1 : SubGopLength + sps->max_num_tid0_ref_pics - 1;
if (sps->profile_idc == 1) ctx->profile = FF_PROFILE_EVC_MAIN;
else ctx->profile = FF_PROFILE_EVC_BASELINE;
if (sps->vui_parameters_present_flag && sps->vui_parameters.timing_info_present_flag) {
int64_t num = sps->vui_parameters.num_units_in_tick;
int64_t den = sps->vui_parameters.time_scale;
if (num != 0 && den != 0)
av_reduce(&ctx->framerate.den, &ctx->framerate.num, num, den, 1 << 30);
} else
ctx->framerate = (AVRational) { 0, 1 };
bit_depth = sps->bit_depth_chroma_minus8 + 8;
ctx->format = AV_PIX_FMT_NONE;
switch (bit_depth) {
case 8:
ctx->format = pix_fmts_8bit[sps->chroma_format_idc];
break;
case 9:
ctx->format = pix_fmts_9bit[sps->chroma_format_idc];
break;
case 10:
ctx->format = pix_fmts_10bit[sps->chroma_format_idc];
break;
case 12:
ctx->format = pix_fmts_12bit[sps->chroma_format_idc];
break;
case 14:
ctx->format = pix_fmts_14bit[sps->chroma_format_idc];
break;
case 16:
ctx->format = pix_fmts_16bit[sps->chroma_format_idc];
break;
}
av_assert0(ctx->format != AV_PIX_FMT_NONE);
break;
}
case EVC_PPS_NUT: {
EVCParserPPS *pps;
pps = ff_evc_parse_pps(ctx, data, nalu_size);
if (!pps) {
av_log(logctx, AV_LOG_ERROR, "PPS parsing error\n");
return AVERROR_INVALIDDATA;
}
break;
}
case EVC_SEI_NUT: // Supplemental Enhancement Information
case EVC_APS_NUT: // Adaptation parameter set
case EVC_FD_NUT: // Filler data
break;
case EVC_IDR_NUT: // Coded slice of a IDR or non-IDR picture
case EVC_NOIDR_NUT: {
EVCParserSliceHeader sh;
const EVCParserSPS *sps;
const EVCParserPPS *pps;
int ret;
ret = evc_parse_slice_header(ctx, &sh, data, nalu_size);
if (ret < 0) {
av_log(logctx, AV_LOG_ERROR, "Slice header parsing error\n");
return ret;
}
switch (sh.slice_type) {
case EVC_SLICE_TYPE_B: {
ctx->pict_type = AV_PICTURE_TYPE_B;
break;
}
case EVC_SLICE_TYPE_P: {
ctx->pict_type = AV_PICTURE_TYPE_P;
break;
}
case EVC_SLICE_TYPE_I: {
ctx->pict_type = AV_PICTURE_TYPE_I;
break;
}
default: {
ctx->pict_type = AV_PICTURE_TYPE_NONE;
}
}
ctx->key_frame = (nalu_type == EVC_IDR_NUT) ? 1 : 0;
// POC (picture order count of the current picture) derivation
// @see ISO/IEC 23094-1:2020(E) 8.3.1 Decoding process for picture order count
pps = ctx->pps[sh.slice_pic_parameter_set_id];
sps = ctx->sps[pps->pps_seq_parameter_set_id];
av_assert0(sps && pps);
if (sps->sps_pocs_flag) {
int PicOrderCntMsb = 0;
ctx->poc.prevPicOrderCntVal = ctx->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 = ctx->poc.PicOrderCntVal & (MaxPicOrderCntLsb - 1);
int prevPicOrderCntMsb = ctx->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;
}
ctx->poc.PicOrderCntVal = PicOrderCntMsb + sh.slice_pic_order_cnt_lsb;
} else {
if (nalu_type == EVC_IDR_NUT) {
ctx->poc.PicOrderCntVal = 0;
ctx->poc.DocOffset = -1;
} else {
int SubGopLength = (int)pow(2.0, sps->log2_sub_gop_length);
if (tid == 0) {
ctx->poc.PicOrderCntVal = ctx->poc.prevPicOrderCntVal + SubGopLength;
ctx->poc.DocOffset = 0;
ctx->poc.prevPicOrderCntVal = ctx->poc.PicOrderCntVal;
} else {
int ExpectedTemporalId;
int PocOffset;
int prevDocOffset = ctx->poc.DocOffset;
ctx->poc.DocOffset = (prevDocOffset + 1) % SubGopLength;
if (ctx->poc.DocOffset == 0) {
ctx->poc.prevPicOrderCntVal += SubGopLength;
ExpectedTemporalId = 0;
} else
ExpectedTemporalId = 1 + (int)log2(ctx->poc.DocOffset);
while (tid != ExpectedTemporalId) {
ctx->poc.DocOffset = (ctx->poc.DocOffset + 1) % SubGopLength;
if (ctx->poc.DocOffset == 0)
ExpectedTemporalId = 0;
else
ExpectedTemporalId = 1 + (int)log2(ctx->poc.DocOffset);
}
PocOffset = (int)(SubGopLength * ((2.0 * ctx->poc.DocOffset + 1) / (int)pow(2.0, tid) - 2));
ctx->poc.PicOrderCntVal = ctx->poc.prevPicOrderCntVal + PocOffset;
}
}
}
ctx->output_picture_number = ctx->poc.PicOrderCntVal;
ctx->key_frame = (nalu_type == EVC_IDR_NUT) ? 1 : 0;
break;
}
}
return 0;
}
void ff_evc_parse_free(EVCParserContext *ctx) {
for (int i = 0; i < EVC_MAX_SPS_COUNT; i++)
av_freep(&ctx->sps[i]);
for (int i = 0; i < EVC_MAX_PPS_COUNT; i++)
av_freep(&ctx->pps[i]);
}