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ffmpeg/libavcodec/evc_parser.c

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/*
* EVC format parser
*
* Copyright (C) 2021 Dawid Kozinski <d.kozinski@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 "avcodec.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,
};
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