/* * EVC format parser * * Copyright (C) 2021 Dawid Kozinski * * 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 "parser.h" #include "bytestream.h" #include "evc.h" #include "evc_parse.h" typedef struct EVCParserContext { EVCParamSets ps; EVCParserPoc poc; int parsed_extradata; } EVCParserContext; #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 }; static int parse_nal_unit(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t *buf, int buf_size) { EVCParserContext *ctx = s->priv_data; GetBitContext gb; int nalu_type, tid; int ret; if (buf_size <= 0) { av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit size: (%d)\n", buf_size); return AVERROR_INVALIDDATA; } ret = init_get_bits8(&gb, buf, buf_size); if (ret < 0) return ret; // @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 if (get_bits1(&gb)) {// forbidden_zero_bit av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit header\n"); return AVERROR_INVALIDDATA; } nalu_type = get_bits(&gb, 6) - 1; 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; } tid = get_bits(&gb, 3); skip_bits(&gb, 5); // nuh_reserved_zero_5bits skip_bits1(&gb); // nuh_extension_flag switch (nalu_type) { case EVC_SPS_NUT: ret = ff_evc_parse_sps(&gb, &ctx->ps); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "SPS parsing error\n"); return ret; } break; case EVC_PPS_NUT: ret = ff_evc_parse_pps(&gb, &ctx->ps); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "PPS parsing error\n"); return ret; } break; case EVC_IDR_NUT: // Coded slice of a IDR or non-IDR picture case EVC_NOIDR_NUT: { const EVCParserPPS *pps; const EVCParserSPS *sps; EVCParserSliceHeader sh; int bit_depth; ret = ff_evc_parse_slice_header(&gb, &sh, &ctx->ps, nalu_type); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "Slice header parsing error\n"); return ret; } pps = ctx->ps.pps[sh.slice_pic_parameter_set_id]; sps = ctx->ps.sps[pps->pps_seq_parameter_set_id]; av_assert0(sps && pps); s->coded_width = sps->pic_width_in_luma_samples; s->coded_height = sps->pic_height_in_luma_samples; if (sps->picture_cropping_flag) { s->width = sps->pic_width_in_luma_samples - sps->picture_crop_left_offset - sps->picture_crop_right_offset; s->height = sps->pic_height_in_luma_samples - sps->picture_crop_top_offset - sps->picture_crop_bottom_offset; } else { s->width = sps->pic_width_in_luma_samples; s->height = sps->pic_height_in_luma_samples; } 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; } } avctx->profile = sps->profile_idc; 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(&avctx->framerate.den, &avctx->framerate.num, num, den, 1 << 30); } else avctx->framerate = (AVRational) { 0, 1 }; bit_depth = sps->bit_depth_chroma_minus8 + 8; s->format = AV_PIX_FMT_NONE; switch (bit_depth) { case 8: s->format = pix_fmts_8bit[sps->chroma_format_idc]; break; case 9: s->format = pix_fmts_9bit[sps->chroma_format_idc]; break; case 10: s->format = pix_fmts_10bit[sps->chroma_format_idc]; break; case 12: s->format = pix_fmts_12bit[sps->chroma_format_idc]; break; case 14: s->format = pix_fmts_14bit[sps->chroma_format_idc]; break; case 16: s->format = pix_fmts_16bit[sps->chroma_format_idc]; break; } s->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 ret = ff_evc_derive_poc(&ctx->ps, &sh, &ctx->poc, nalu_type, tid); if (ret < 0) return ret; s->output_picture_number = ctx->poc.PicOrderCntVal; break; } case EVC_SEI_NUT: // Supplemental Enhancement Information case EVC_APS_NUT: // Adaptation parameter set case EVC_FD_NUT: // Filler data default: break; } return 0; } /** * Parse NAL units of found picture and decode some basic information. * * @param s codec 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, AVCodecContext *avctx, const uint8_t *buf, int buf_size) { const uint8_t *data = buf; int data_size = buf_size; while (data_size > 0) { int nalu_size = 0; int ret; // Buffer size is not enough for buffer to store NAL unit 4-bytes prefix (length) if (data_size < EVC_NALU_LENGTH_PREFIX_SIZE) return AVERROR_INVALIDDATA; nalu_size = evc_read_nal_unit_length(data, data_size, avctx); data += EVC_NALU_LENGTH_PREFIX_SIZE; data_size -= EVC_NALU_LENGTH_PREFIX_SIZE; if (data_size < nalu_size) return AVERROR_INVALIDDATA; ret = parse_nal_unit(s, avctx, data, nalu_size); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "Parsing of NAL unit failed\n"); return AVERROR_INVALIDDATA; } data += nalu_size; data_size -= nalu_size; } return 0; } // Decoding nal units from evcC (EVCDecoderConfigurationRecord) // @see @see ISO/IEC 14496-15:2021 Coding of audio-visual objects - Part 15: section 12.3.3.2 static int decode_extradata(AVCodecParserContext *s, AVCodecContext *avctx) { const uint8_t *data = avctx->extradata; int size = avctx->extradata_size; int ret = 0; GetByteContext gb; bytestream2_init(&gb, data, size); if (!data || size <= 0) return -1; // extradata is encoded as evcC format. if (data[0] == 1) { int num_of_arrays; // indicates the number of arrays of NAL units of the indicated type(s) int nalu_length_field_size; // indicates the length in bytes of the NALUnitLenght field in EVC video stream sample in the stream // The value of this field shall be one of 0, 1, or 3 corresponding to a length encoded with 1, 2, or 4 bytes, respectively. if (bytestream2_get_bytes_left(&gb) < 18) { av_log(avctx, AV_LOG_ERROR, "evcC %d too short\n", size); return AVERROR_INVALIDDATA; } bytestream2_skip(&gb, 16); // @see ISO/IEC 14496-15:2021 Coding of audio-visual objects - Part 15: section 12.3.3.3 // LengthSizeMinusOne plus 1 indicates the length in bytes of the NALUnitLength field in a EVC video stream sample in the stream to which this configuration record applies. For example, a size of one byte is indicated with a value of 0. // The value of this field shall be one of 0, 1, or 3 corresponding to a length encoded with 1, 2, or 4 bytes, respectively. nalu_length_field_size = (bytestream2_get_byte(&gb) & 3) + 1; if( nalu_length_field_size != 1 && nalu_length_field_size != 2 && nalu_length_field_size != 4 ) { av_log(avctx, AV_LOG_ERROR, "The length in bytes of the NALUnitLenght field in a EVC video stream has unsupported value of %d\n", nalu_length_field_size); return AVERROR_INVALIDDATA; } num_of_arrays = bytestream2_get_byte(&gb); /* Decode nal units from evcC. */ for (int i = 0; i < num_of_arrays; i++) { // @see ISO/IEC 14496-15:2021 Coding of audio-visual objects - Part 15: section 12.3.3.3 // NAL_unit_type indicates the type of the NAL units in the following array (which shall be all of that type); // - it takes a value as defined in ISO/IEC 23094-1; // - it is restricted to take one of the values indicating a SPS, PPS, APS, or SEI NAL unit. int nal_unit_type = bytestream2_get_byte(&gb) & 0x3f; int num_nalus = bytestream2_get_be16(&gb); for (int j = 0; j < num_nalus; j++) { int nal_unit_length = bytestream2_get_be16(&gb); if (bytestream2_get_bytes_left(&gb) < nal_unit_length) { av_log(avctx, AV_LOG_ERROR, "Invalid NAL unit size in extradata.\n"); return AVERROR_INVALIDDATA; } if( nal_unit_type == EVC_SPS_NUT || nal_unit_type == EVC_PPS_NUT || nal_unit_type == EVC_APS_NUT || nal_unit_type == EVC_SEI_NUT ) { if (parse_nal_unit(s, avctx, gb.buffer, nal_unit_length) != 0) { av_log(avctx, AV_LOG_ERROR, "Parsing of NAL unit failed\n"); return AVERROR_INVALIDDATA; } } bytestream2_skip(&gb, nal_unit_length); } } } else return -1; return ret; } static int evc_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size) { int next; int ret; EVCParserContext *ctx = s->priv_data; s->picture_structure = AV_PICTURE_STRUCTURE_FRAME; s->key_frame = 0; if (avctx->extradata && !ctx->parsed_extradata) { decode_extradata(s, avctx); ctx->parsed_extradata = 1; } next = buf_size; ret = parse_nal_units(s, avctx, buf, buf_size); if(ret < 0) { *poutbuf = NULL; *poutbuf_size = 0; return buf_size; } // poutbuf contains just one Access Unit *poutbuf = buf; *poutbuf_size = buf_size; return next; } static void evc_parser_close(AVCodecParserContext *s) { EVCParserContext *ctx = s->priv_data; ff_evc_ps_free(&ctx->ps); } const AVCodecParser ff_evc_parser = { .codec_ids = { AV_CODEC_ID_EVC }, .priv_data_size = sizeof(EVCParserContext), .parser_parse = evc_parse, .parser_close = evc_parser_close, };