[FFmpeg-devel] [PATCH v14 2/9] avcodec/evc_parser: Added parser implementation for EVC format

Dawid Kozinski d.kozinski at samsung.com
Mon Oct 24 10:39:05 EEST 2022


Signed-off-by: Dawid Kozinski <d.kozinski at samsung.com>
---
 libavcodec/Makefile     |   1 +
 libavcodec/evc.h        | 155 +++++++++
 libavcodec/evc_parser.c | 740 ++++++++++++++++++++++++++++++++++++++++
 libavcodec/parsers.c    |   1 +
 4 files changed, 897 insertions(+)
 create mode 100644 libavcodec/evc.h
 create mode 100644 libavcodec/evc_parser.c

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 7761620de7..ee276ebefb 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1137,6 +1137,7 @@ OBJS-$(CONFIG_DVAUDIO_PARSER)          += dvaudio_parser.o
 OBJS-$(CONFIG_DVBSUB_PARSER)           += dvbsub_parser.o
 OBJS-$(CONFIG_DVD_NAV_PARSER)          += dvd_nav_parser.o
 OBJS-$(CONFIG_DVDSUB_PARSER)           += dvdsub_parser.o
+OBJS-$(CONFIG_EVC_PARSER)              += evc_parser.o
 OBJS-$(CONFIG_FLAC_PARSER)             += flac_parser.o flacdata.o flac.o
 OBJS-$(CONFIG_FTR_PARSER)              += ftr_parser.o
 OBJS-$(CONFIG_G723_1_PARSER)           += g723_1_parser.o
diff --git a/libavcodec/evc.h b/libavcodec/evc.h
new file mode 100644
index 0000000000..b3e648796c
--- /dev/null
+++ b/libavcodec/evc.h
@@ -0,0 +1,155 @@
+/*
+ * EVC definitions and enums
+ * Copyright (c) 2022 Dawid Kozinski <d.kozinski at samsung.com>
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_EVC_H
+#define AVCODEC_EVC_H
+
+// The length field that indicates the length in bytes of the following NAL unit is configured to be of 4 bytes
+#define EVC_NAL_UNIT_LENGTH_BYTE        (4)  /* byte */
+#define EVC_NAL_HEADER_SIZE             (2)  /* byte */
+
+/**
+ * @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
+ */
+enum EVCNALUnitType {
+    EVC_NOIDR_NUT            = 0,   /* Coded slice of a non-IDR picture */
+    EVC_IDR_NUT              = 1,   /* Coded slice of an IDR picture */
+    EVC_RSV_VCL_NUT02        = 2,
+    EVC_RSV_VCL_NUT03        = 3,
+    EVC_RSV_VCL_NUT04        = 4,
+    EVC_RSV_VCL_NUT05        = 5,
+    EVC_RSV_VCL_NUT06        = 6,
+    EVC_RSV_VCL_NUT07        = 7,
+    EVC_RSV_VCL_NUT08        = 8,
+    EVC_RSV_VCL_NUT09        = 9,
+    EVC_RSV_VCL_NUT10        = 10,
+    EVC_RSV_VCL_NUT11        = 11,
+    EVC_RSV_VCL_NUT12        = 12,
+    EVC_RSV_VCL_NUT13        = 13,
+    EVC_RSV_VCL_NUT14        = 14,
+    EVC_RSV_VCL_NUT15        = 15,
+    EVC_RSV_VCL_NUT16        = 16,
+    EVC_RSV_VCL_NUT17        = 17,
+    EVC_RSV_VCL_NUT18        = 18,
+    EVC_RSV_VCL_NUT19        = 19,
+    EVC_RSV_VCL_NUT20        = 20,
+    EVC_RSV_VCL_NUT21        = 21,
+    EVC_RSV_VCL_NUT22        = 22,
+    EVC_RSV_VCL_NUT23        = 23,
+    EVC_SPS_NUT              = 24,  /* Sequence parameter set */
+    EVC_PPS_NUT              = 25,  /* Picture paremeter set */
+    EVC_APS_NUT              = 26,  /* Adaptation parameter set */
+    EVC_FD_NUT               = 27,  /* Filler data */
+    EVC_SEI_NUT              = 28,  /* Supplemental enhancement information */
+    EVC_RSV_NONVCL29         = 29,
+    EVC_RSV_NONVCL30         = 30,
+    EVC_RSV_NONVCL31         = 31,
+    EVC_RSV_NONVCL32         = 32,
+    EVC_RSV_NONVCL33         = 33,
+    EVC_RSV_NONVCL34         = 34,
+    EVC_RSV_NONVCL35         = 35,
+    EVC_RSV_NONVCL36         = 36,
+    EVC_RSV_NONVCL37         = 37,
+    EVC_RSV_NONVCL38         = 38,
+    EVC_RSV_NONVCL39         = 39,
+    EVC_RSV_NONVCL40         = 40,
+    EVC_RSV_NONVCL41         = 41,
+    EVC_RSV_NONVCL42         = 42,
+    EVC_RSV_NONVCL43         = 43,
+    EVC_RSV_NONVCL44         = 44,
+    EVC_RSV_NONVCL45         = 45,
+    EVC_RSV_NONVCL46         = 46,
+    EVC_RSV_NONVCL47         = 47,
+    EVC_RSV_NONVCL48         = 48,
+    EVC_RSV_NONVCL49         = 49,
+    EVC_RSV_NONVCL50         = 50,
+    EVC_RSV_NONVCL51         = 51,
+    EVC_RSV_NONVCL52         = 52,
+    EVC_RSV_NONVCL53         = 53,
+    EVC_RSV_NONVCL54         = 54,
+    EVC_RSV_NONVCL55         = 55,
+    EVC_UNSPEC_NUT56         = 56,
+    EVC_UNSPEC_NUT57         = 57,
+    EVC_UNSPEC_NUT58         = 58,
+    EVC_UNSPEC_NUT59         = 59,
+    EVC_UNSPEC_NUT60         = 60,
+    EVC_UNSPEC_NUT61         = 61,
+    EVC_UNSPEC_NUT62         = 62
+};
+
+// slice type
+// @see ISO_IEC_23094-1_2020 7.4.5 Slice header semantics
+//
+enum EVCSliceType {
+    EVC_SLICE_TYPE_B = 0,
+    EVC_SLICE_TYPE_P = 1,
+    EVC_SLICE_TYPE_I = 2
+};
+
+enum {
+    // 7.4.3.2: aps_video_parameter_set_id is u(4).
+    EVC_MAX_APS_COUNT = 32,
+
+    // 7.4.3.1: sps_seq_parameter_set_id is in [0, 15].
+    EVC_MAX_SPS_COUNT = 16,
+
+    // 7.4.3.2: pps_pic_parameter_set_id is in [0, 63].
+    EVC_MAX_PPS_COUNT = 64,
+
+    // 7.4.5: slice header slice_pic_parameter_set_id in [0, 63]
+    EVC_MAX_SH_COUNT = 64,
+
+    // E.3.2: cpb_cnt_minus1[i] is in [0, 31].
+    EVC_MAX_CPB_CNT = 32,
+
+    // A.4.1: in table A.1 the highest level allows a MaxLumaPs of 35 651 584.
+    EVC_MAX_LUMA_PS = 35651584,
+
+    EVC_MAX_NUM_REF_PICS = 21,
+
+    EVC_MAX_NUM_RPLS = 32,
+
+    // A.4.1: pic_width_in_luma_samples and pic_height_in_luma_samples are
+    // constrained to be not greater than sqrt(MaxLumaPs * 8).  Hence height/
+    // width are bounded above by sqrt(8 * 35651584) = 16888.2 samples.
+    EVC_MAX_WIDTH  = 16888,
+    EVC_MAX_HEIGHT = 16888,
+
+    // A.4.1: table A.1 allows at most 22 tile rows for any level.
+    EVC_MAX_TILE_ROWS    = 22,
+    // A.4.1: table A.1 allows at most 20 tile columns for any level.
+    EVC_MAX_TILE_COLUMNS = 20,
+
+    // A.4.1: table A.1 allows at most 600 slice segments for any level.
+    EVC_MAX_SLICE_SEGMENTS = 600,
+
+    // 7.4.7.1: in the worst case (tiles_enabled_flag and
+    // entropy_coding_sync_enabled_flag are both set), entry points can be
+    // placed at the beginning of every Ctb row in every tile, giving an
+    // upper bound of (num_tile_columns_minus1 + 1) * PicHeightInCtbsY - 1.
+    // Only a stream with very high resolution and perverse parameters could
+    // get near that, though, so set a lower limit here with the maximum
+    // possible value for 4K video (at most 135 16x16 Ctb rows).
+    HEVC_MAX_ENTRY_POINT_OFFSETS = EVC_MAX_TILE_COLUMNS * 135,
+};
+
+#endif // AVCODEC_EVC_H
diff --git a/libavcodec/evc_parser.c b/libavcodec/evc_parser.c
new file mode 100644
index 0000000000..ab0b199b59
--- /dev/null
+++ b/libavcodec/evc_parser.c
@@ -0,0 +1,740 @@
+/*
+ * EVC format parser
+ *
+ * Copyright (C) 2021 Dawid Kozinski <d.kozinski at samsung.com>
+ *
+ * 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 "libavutil/common.h"
+#include "parser.h"
+#include "golomb.h"
+#include "evc.h"
+
+// rpl structure
+typedef struct RefPicListStruct {
+    int poc;
+    int tid;
+    int ref_pic_num;
+    int ref_pic_active_num;
+    int ref_pics[EVC_MAX_NUM_REF_PICS];
+    char pic_type;
+
+} RefPicListStruct;
+
+// The sturcture reflects SPS RBSP(raw byte sequence payload) layout
+// @see ISO_IEC_23094-1 section 7.3.2.1
+//
+// The following descriptors specify the parsing process of each element
+// u(n) - unsigned integer using n bits
+// ue(v) - unsigned integer 0-th order Exp_Golomb-coded syntax element with the left bit first
+typedef struct EVCParserSPS {
+    int sps_seq_parameter_set_id;   // ue(v)
+    int profile_idc;                // u(8)
+    int level_idc;                  // u(8)
+    int toolset_idc_h;              // u(32)
+    int toolset_idc_l;              // u(32)
+    int chroma_format_idc;          // ue(v)
+    int pic_width_in_luma_samples;  // ue(v)
+    int pic_height_in_luma_samples; // ue(v)
+    int bit_depth_luma_minus8;      // ue(v)
+    int bit_depth_chroma_minus8;    // ue(v)
+
+    int sps_btt_flag;                           // u(1)
+    int log2_ctu_size_minus5;                   // ue(v)
+    int log2_min_cb_size_minus2;                // ue(v)
+    int log2_diff_ctu_max_14_cb_size;           // ue(v)
+    int log2_diff_ctu_max_tt_cb_size;           // ue(v)
+    int log2_diff_min_cb_min_tt_cb_size_minus2; // ue(v)
+
+    int sps_suco_flag;                       // u(1)
+    int log2_diff_ctu_size_max_suco_cb_size; // ue(v)
+    int log2_diff_max_suco_min_suco_cb_size; // ue(v)
+
+    int sps_admvp_flag;     // u(1)
+    int sps_affine_flag;    // u(1)
+    int sps_amvr_flag;      // u(1)
+    int sps_dmvr_flag;      // u(1)
+    int sps_mmvd_flag;      // u(1)
+    int sps_hmvp_flag;      // u(1)
+
+    int sps_eipd_flag;                 // u(1)
+    int sps_ibc_flag;                  // u(1)
+    int log2_max_ibc_cand_size_minus2; // ue(v)
+
+    int sps_cm_init_flag; // u(1)
+    int sps_adcc_flag;    // u(1)
+
+    int sps_iqt_flag; // u(1)
+    int sps_ats_flag; // u(1)
+
+    int sps_addb_flag;   // u(1)
+    int sps_alf_flag;    // u(1)
+    int sps_htdf_flag;   // u(1)
+    int sps_rpl_flag;    // u(1)
+    int sps_pocs_flag;   // u(1)
+    int sps_dquant_flag; // u(1)
+    int sps_dra_flag;    // u(1)
+
+    int log2_max_pic_order_cnt_lsb_minus4; // ue(v)
+    int log2_sub_gop_length;               // ue(v)
+    int log2_ref_pic_gap_length;           // ue(v)
+
+    int max_num_tid0_ref_pics; // ue(v)
+
+    int sps_max_dec_pic_buffering_minus1; // ue(v)
+    int long_term_ref_pic_flag;           // u(1)
+    int rpl1_same_as_rpl0_flag;           // u(1)
+    int num_ref_pic_list_in_sps[2];       // ue(v)
+    RefPicListStruct rpls[2][EVC_MAX_NUM_RPLS];
+
+    int picture_cropping_flag;      // u(1)
+    int picture_crop_left_offset;   // ue(v)
+    int picture_crop_right_offset;  // ue(v)
+    int picture_crop_top_offset;    // ue(v)
+    int picture_crop_bottom_offset; // ue(v)
+
+    // @note
+    // Currently the structure does not reflect the entire SPS RBSP layout.
+    // It contains only the fields that are necessary to read from the NAL unit all the values
+    // necessary for the correct initialization of the AVCodecContext structure.
+
+    // @note
+    // If necessary, add the missing fields to the structure to reflect
+    // the contents of the entire NAL unit of the SPS type
+
+} EVCParserSPS;
+
+typedef struct EVCParserPPS {
+    int pps_pic_parameter_set_id;                           // ue(v)
+    int pps_seq_parameter_set_id;                           // ue(v)
+    int num_ref_idx_default_active_minus1[2];               // ue(v)
+    int additional_lt_poc_lsb_len;                          // ue(v)
+    int rpl1_idx_present_flag;                              // u(1)
+    int single_tile_in_pic_flag;                            // u(1)
+    int num_tile_columns_minus1;                            // ue(v)
+    int num_tile_rows_minus1;                               // ue(v)
+    int uniform_tile_spacing_flag;                          // u(1)
+    int tile_column_width_minus1[EVC_MAX_TILE_ROWS];        // ue(v)
+    int tile_row_height_minus1[EVC_MAX_TILE_COLUMNS];          // ue(v)
+    int loop_filter_across_tiles_enabled_flag;              // u(1)
+    int tile_offset_len_minus1;                             // ue(v)
+    int tile_id_len_minus1;                                 // ue(v)
+    int explicit_tile_id_flag;                              // u(1)
+    int tile_id_val[EVC_MAX_TILE_ROWS][EVC_MAX_TILE_COLUMNS];  // u(v)
+    int pic_dra_enabled_flag;                               // u(1)
+    int pic_dra_aps_id;                                     // u(5)
+    int arbitrary_slice_present_flag;                       // u(1)
+    int constrained_intra_pred_flag;                        // u(1)
+    int cu_qp_delta_enabled_flag;                           // u(1)
+    int log2_cu_qp_delta_area_minus6;                       // ue(v)
+
+} EVCParserPPS;
+
+// The sturcture reflects Slice Header RBSP(raw byte sequence payload) layout
+// @see ISO_IEC_23094-1 section 7.3.2.6
+//
+// The following descriptors specify the parsing process of each element
+// u(n) - unsigned integer using n bits
+// ue(v) - unsigned integer 0-th order Exp_Golomb-coded syntax element with the left bit first
+// u(n) - unsigned integer using n bits.
+//        When n is "v" in the syntax table, the number of bits varies in a manner dependent on the value of other syntax elements.
+typedef struct EVCParserSliceHeader {
+    int slice_pic_parameter_set_id;                                     // ue(v)
+    int single_tile_in_slice_flag;                                      // u(1)
+    int first_tile_id;                                                  // u(v)
+    int arbitrary_slice_flag;                                           // u(1)
+    int last_tile_id;                                                   // u(v)
+    int num_remaining_tiles_in_slice_minus1;                            // ue(v)
+    int delta_tile_id_minus1[EVC_MAX_TILE_ROWS * EVC_MAX_TILE_COLUMNS];    // ue(v)
+
+    int slice_type;                                                     // ue(v)
+
+    // @note
+    // Currently the structure does not reflect the entire Slice Header RBSP layout.
+    // It contains only the fields that are necessary to read from the NAL unit all the values
+    // necessary for the correct initialization of the AVCodecContext structure.
+
+    // @note
+    // If necessary, add the missing fields to the structure to reflect
+    // the contents of the entire NAL unit of the SPS type
+
+} EVCParserSliceHeader;
+
+typedef struct EVCParserContext {
+    ParseContext pc;
+    EVCParserSPS sps[EVC_MAX_SPS_COUNT];
+    EVCParserPPS pps[EVC_MAX_PPS_COUNT];
+    EVCParserSliceHeader slice_header[EVC_MAX_PPS_COUNT];
+    int is_avc;
+    int nal_length_size;
+    int to_read;
+    int incomplete_nalu_prefix_read; // The flag is set to 1 when an incomplete NAL unit prefix has been read
+
+} EVCParserContext;
+
+static int get_nalu_type(const uint8_t *bits, int bits_size, AVCodecContext *avctx)
+{
+    int unit_type_plus1 = 0;
+
+    if (bits_size >= EVC_NAL_HEADER_SIZE) {
+        unsigned char *p = (unsigned char *)bits;
+        // forbidden_zero_bit
+        if ((p[0] & 0x80) != 0)
+            return -1;
+
+        // nal_unit_type
+        unit_type_plus1 = (p[0] >> 1) & 0x3F;
+    }
+
+    return unit_type_plus1 - 1;
+}
+
+static uint32_t read_nal_unit_length(const uint8_t *bits, int bits_size, AVCodecContext *avctx)
+{
+    uint32_t nalu_len = 0;
+
+    if (bits_size >= EVC_NAL_UNIT_LENGTH_BYTE) {
+
+        int t = 0;
+        unsigned char *p = (unsigned char *)bits;
+
+        for (int i = 0; i < EVC_NAL_UNIT_LENGTH_BYTE; i++)
+            t = (t << 8) | p[i];
+
+        nalu_len = t;
+        if (nalu_len == 0)
+            return 0;
+    }
+
+    return nalu_len;
+}
+
+// @see ISO_IEC_23094-1 (7.3.2.1 SPS RBSP syntax)
+static EVCParserSPS *parse_sps(const uint8_t *bs, int bs_size, EVCParserContext *ev)
+{
+    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;
+
+    sps = &ev->sps[sps_seq_parameter_set_id];
+    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);
+    }
+
+    // @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
+//
+static EVCParserPPS *parse_pps(const uint8_t *bs, int bs_size, EVCParserContext *ev)
+{
+    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;
+
+    pps = &ev->pps[pps_pic_parameter_set_id];
+
+    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)
+        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 EVCParserSliceHeader *parse_slice_header(const uint8_t *bs, int bs_size, EVCParserContext *ev)
+{
+    GetBitContext gb;
+    EVCParserSliceHeader *sh;
+    EVCParserPPS *pps;
+    int num_tiles_in_slice = 0;
+    int slice_pic_parameter_set_id;
+
+    if (init_get_bits8(&gb, bs, bs_size) < 0)
+        return NULL;
+
+    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 NULL;
+
+    sh = &ev->slice_header[slice_pic_parameter_set_id];
+    pps = &ev->pps[slice_pic_parameter_set_id];
+
+    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);
+
+    // @note
+    // If necessary, add the missing fields to the EVCParserSliceHeader structure
+    // and then extend parser implementation
+
+    return sh;
+}
+
+/**
+ * Parse NAL units of found picture and decode some basic information.
+ *
+ * @param s parser context.
+ * @param avctx codec context.
+ * @param buf buffer with field/frame data.
+ * @param buf_size size of the buffer.
+ */
+static int parse_nal_units(AVCodecParserContext *s, const uint8_t *buf,
+                           int buf_size, AVCodecContext *avctx)
+{
+    EVCParserContext *ev = s->priv_data;
+    int nalu_type, nalu_size;
+
+    s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
+    s->key_frame = -1;
+
+    nalu_size = read_nal_unit_length(buf, buf_size, avctx);
+    if (nalu_size <= 0) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit size: (%d)\n", nalu_size);
+        return AVERROR_INVALIDDATA;
+    }
+
+    buf += EVC_NAL_UNIT_LENGTH_BYTE;
+    buf_size -= EVC_NAL_UNIT_LENGTH_BYTE;
+
+    // @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 = get_nalu_type(buf, buf_size, avctx);
+    if (nalu_type < EVC_NOIDR_NUT || nalu_type > EVC_UNSPEC_NUT62) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit type: (%d)\n", nalu_type);
+        return AVERROR_INVALIDDATA;
+    }
+
+    buf += EVC_NAL_HEADER_SIZE;
+    buf_size -= EVC_NAL_HEADER_SIZE;
+
+    if (nalu_type == EVC_SPS_NUT) {
+        EVCParserSPS *sps;
+
+        sps = parse_sps(buf, buf_size, ev);
+        if (!sps) {
+            av_log(avctx, AV_LOG_ERROR, "SPS parsing error\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        s->coded_width         = sps->pic_width_in_luma_samples;
+        s->coded_height        = sps->pic_height_in_luma_samples;
+        s->width               = sps->pic_width_in_luma_samples;
+        s->height              = sps->pic_height_in_luma_samples;
+
+        if (sps->profile_idc == 1) avctx->profile = FF_PROFILE_EVC_MAIN;
+        else avctx->profile = FF_PROFILE_EVC_BASELINE;
+
+        switch (sps->chroma_format_idc) {
+        case 0: /* YCBCR400_10LE */
+            av_log(avctx, AV_LOG_ERROR, "YCBCR400_10LE: Not supported chroma format\n");
+            s->format = AV_PIX_FMT_GRAY10LE;
+            return -1;
+        case 1: /* YCBCR420_10LE */
+            s->format = AV_PIX_FMT_YUV420P10LE;
+            break;
+        case 2: /* YCBCR422_10LE */
+            av_log(avctx, AV_LOG_ERROR, "YCBCR422_10LE: Not supported chroma format\n");
+            s->format = AV_PIX_FMT_YUV422P10LE;
+            return -1;
+        case 3: /* YCBCR444_10LE */
+            av_log(avctx, AV_LOG_ERROR, "YCBCR444_10LE: Not supported chroma format\n");
+            s->format = AV_PIX_FMT_YUV444P10LE;
+            return -1;
+        default:
+            s->format = AV_PIX_FMT_NONE;
+            av_log(avctx, AV_LOG_ERROR, "Unknown supported chroma format\n");
+            return -1;
+        }
+    } else if (nalu_type == EVC_PPS_NUT) {
+        EVCParserPPS *pps;
+
+        pps = parse_pps(buf, buf_size, ev);
+        if (!pps) {
+            av_log(avctx, AV_LOG_ERROR, "PPS parsing error\n");
+            return AVERROR_INVALIDDATA;
+        }
+    } else if (nalu_type == EVC_SEI_NUT) // Supplemental Enhancement Information
+        return 0;
+    else if (nalu_type == EVC_IDR_NUT || nalu_type == EVC_NOIDR_NUT) { // Coded slice of a IDR or non-IDR picture
+        EVCParserSliceHeader *sh;
+
+        sh = parse_slice_header(buf, buf_size, ev);
+        if (!sh) {
+            av_log(avctx, AV_LOG_ERROR, "Slice header parsing error\n");
+            return AVERROR_INVALIDDATA;
+        }
+        switch (sh->slice_type) {
+        case EVC_SLICE_TYPE_B: {
+            s->pict_type =  AV_PICTURE_TYPE_B;
+            break;
+        }
+        case EVC_SLICE_TYPE_P: {
+            s->pict_type =  AV_PICTURE_TYPE_P;
+            break;
+        }
+        case EVC_SLICE_TYPE_I: {
+            s->pict_type =  AV_PICTURE_TYPE_I;
+            break;
+        }
+        default: {
+            s->pict_type =  AV_PICTURE_TYPE_NONE;
+        }
+        }
+        s->key_frame = (nalu_type == EVC_IDR_NUT) ? 1 : 0;
+    } else {
+        av_log(avctx, AV_LOG_ERROR, "Unknown NAL unit type: %d\n", nalu_type);
+        return 0;
+    }
+
+    return 0;
+}
+
+/**
+ * Find the end of the current frame in the bitstream.
+ * @return the position of the first byte of the next frame, or END_NOT_FOUND
+ */
+static int evc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
+                              int buf_size, AVCodecContext *avctx)
+{
+    EVCParserContext *ev = s->priv_data;
+
+    if (!ev->to_read) {
+        int nal_unit_size = 0;
+        int next = END_NOT_FOUND;
+
+        // This is the case when buffer size is not enough for buffer to store NAL unit length
+        if (buf_size < EVC_NAL_UNIT_LENGTH_BYTE) {
+            ev->to_read = EVC_NAL_UNIT_LENGTH_BYTE;
+            ev->nal_length_size = buf_size;
+            ev->incomplete_nalu_prefix_read  = 1;
+
+            return END_NOT_FOUND;
+        }
+
+        nal_unit_size = read_nal_unit_length(buf, buf_size, avctx);
+        ev->nal_length_size = EVC_NAL_UNIT_LENGTH_BYTE;
+
+        next = nal_unit_size + EVC_NAL_UNIT_LENGTH_BYTE;
+        ev->to_read = next;
+        if (next < buf_size)
+            return next;
+        else
+            return END_NOT_FOUND;
+    } else if (ev->to_read > buf_size)
+        return END_NOT_FOUND;
+    else {
+        if (ev->incomplete_nalu_prefix_read  == 1) {
+            EVCParserContext *ev = s->priv_data;
+            ParseContext *pc = &ev->pc;
+            uint8_t nalu_len[EVC_NAL_UNIT_LENGTH_BYTE] = {0};
+            int nal_unit_size = 0;
+
+            // 1. pc->buffer contains previously read bytes of NALU prefix
+            // 2. buf contains the rest of NAL unit prefix bytes
+            //
+            // ~~~~~~~
+            // EXAMPLE
+            // ~~~~~~~
+            //
+            // In the following example we assumed that the number of already read NAL Unit prefix bytes is equal 1
+            //
+            // ----------
+            // pc->buffer -> conatins already read bytes
+            // ----------
+            //              __ pc->index == 1
+            //             |
+            //             V
+            // -------------------------------------------------------
+            // |   0   |   1   |   2   |   3   |   4   | ... |   N   |
+            // -------------------------------------------------------
+            // |  0x00 |  0xXX |  0xXX |  0xXX |  0xXX | ... |  0xXX |
+            // -------------------------------------------------------
+            //
+            // ----------
+            // buf -> contains newly read bytes
+            // ----------
+            // -------------------------------------------------------
+            // |   0   |   1   |   2   |   3   |   4   | ... |   N   |
+            // -------------------------------------------------------
+            // |  0x00 |  0x00 |  0x3C |  0xXX |  0xXX | ... |  0xXX |
+            // -------------------------------------------------------
+            //
+            for (int i = 0; i < EVC_NAL_UNIT_LENGTH_BYTE; i++) {
+                if (i < pc->index)
+                    nalu_len[i] = pc->buffer[i];
+                else
+                    nalu_len[i] = buf[i - pc->index];
+            }
+
+            // ----------
+            // nalu_len
+            // ----------
+            // ---------------------------------
+            // |   0   |   1   |   2   |   3   |
+            // ---------------------------------
+            // |  0x00 |  0x00 |  0x00 |  0x3C |
+            // ---------------------------------
+            // | NALU LENGTH                   |
+            // ---------------------------------
+            // NAL Unit lenght =  60 (0x0000003C)
+
+            nal_unit_size = read_nal_unit_length(nalu_len, EVC_NAL_UNIT_LENGTH_BYTE, avctx);
+
+            ev->to_read = nal_unit_size + EVC_NAL_UNIT_LENGTH_BYTE - pc->index;
+
+            ev->incomplete_nalu_prefix_read = 0;
+
+            if (ev->to_read > buf_size)
+                return END_NOT_FOUND;
+            else
+                return ev->to_read;
+        }
+        return ev->to_read;
+    }
+
+    return END_NOT_FOUND;
+}
+
+static int evc_parser_init(AVCodecParserContext *s)
+{
+    EVCParserContext *ev = s->priv_data;
+
+    ev->nal_length_size = EVC_NAL_UNIT_LENGTH_BYTE;
+    ev->incomplete_nalu_prefix_read = 0;
+
+    return 0;
+}
+
+static int evc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                     const uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size)
+{
+    int next;
+    EVCParserContext *ev = s->priv_data;
+    ParseContext *pc = &ev->pc;
+    int is_dummy_buf = !buf_size;
+    const uint8_t *dummy_buf = buf;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES)
+        next = buf_size;
+    else {
+        next = evc_find_frame_end(s, buf, buf_size, avctx);
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf      = NULL;
+            *poutbuf_size = 0;
+            ev->to_read -= buf_size;
+            return buf_size;
+        }
+    }
+
+    is_dummy_buf &= (dummy_buf == buf);
+
+    if (!is_dummy_buf) {
+        if (parse_nal_units(s, buf, buf_size, avctx) == AVERROR_INVALIDDATA) {
+            *poutbuf      = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    // poutbuf contains just one NAL unit
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+    ev->to_read  -= next;
+
+    return next;
+}
+
+const AVCodecParser ff_evc_parser = {
+    .codec_ids      = { AV_CODEC_ID_EVC },
+    .priv_data_size = sizeof(EVCParserContext),
+    .parser_init    = evc_parser_init,
+    .parser_parse   = evc_parse,
+    .parser_close   = ff_parse_close,
+};
diff --git a/libavcodec/parsers.c b/libavcodec/parsers.c
index d355808018..2c077ec3ae 100644
--- a/libavcodec/parsers.c
+++ b/libavcodec/parsers.c
@@ -41,6 +41,7 @@ extern const AVCodecParser ff_dvaudio_parser;
 extern const AVCodecParser ff_dvbsub_parser;
 extern const AVCodecParser ff_dvdsub_parser;
 extern const AVCodecParser ff_dvd_nav_parser;
+extern const AVCodecParser ff_evc_parser;
 extern const AVCodecParser ff_flac_parser;
 extern const AVCodecParser ff_ftr_parser;
 extern const AVCodecParser ff_g723_1_parser;
-- 
2.17.1



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