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HEVC standard supports multi-layer streams (ITU-T H.265 02/2018 Annex F). Each NAL unit belongs to a particular layer defined by nuh_layer_id in the header. Currently, all NAL units that do not belong to a base layer are automatically removed in ff_h2645_packet_split(). Some data may therefore be lost when future filters/decoders are designed to support multi-layer streams. A better approach is to forward nuh_layer_id > 0 packets and let blocks down the chain decide how to process them. The condition to remove packets has been moved to hevcdec and cbs. Found-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> Signed-off-by: Andriy Gelman <andriy.gelman@gmail.com> Signed-off-by: James Almer <jamrial@gmail.com>
139 lines
3.9 KiB
C
139 lines
3.9 KiB
C
/*
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* H.264/HEVC common parsing code
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_H2645_PARSE_H
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#define AVCODEC_H2645_PARSE_H
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#include <stdint.h>
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#include "libavutil/buffer.h"
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#include "avcodec.h"
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#include "get_bits.h"
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#define MAX_MBPAIR_SIZE (256*1024) // a tighter bound could be calculated if someone cares about a few bytes
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typedef struct H2645NAL {
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uint8_t *rbsp_buffer;
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int size;
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const uint8_t *data;
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/**
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* Size, in bits, of just the data, excluding the stop bit and any trailing
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* padding. I.e. what HEVC calls SODB.
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*/
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int size_bits;
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int raw_size;
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const uint8_t *raw_data;
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GetBitContext gb;
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/**
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* NAL unit type
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*/
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int type;
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/**
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* HEVC only, nuh_temporal_id_plus_1 - 1
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*/
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int temporal_id;
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/*
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* HEVC only, identifier of layer to which nal unit belongs
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*/
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int nuh_layer_id;
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int skipped_bytes;
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int skipped_bytes_pos_size;
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int *skipped_bytes_pos;
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/**
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* H.264 only, nal_ref_idc
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*/
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int ref_idc;
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} H2645NAL;
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typedef struct H2645RBSP {
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uint8_t *rbsp_buffer;
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AVBufferRef *rbsp_buffer_ref;
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int rbsp_buffer_alloc_size;
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int rbsp_buffer_size;
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} H2645RBSP;
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/* an input packet split into unescaped NAL units */
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typedef struct H2645Packet {
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H2645NAL *nals;
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H2645RBSP rbsp;
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int nb_nals;
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int nals_allocated;
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unsigned nal_buffer_size;
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} H2645Packet;
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/**
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* Extract the raw (unescaped) bitstream.
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*/
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int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp,
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H2645NAL *nal, int small_padding);
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/**
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* Split an input packet into NAL units.
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*
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* If data == raw_data holds true for a NAL unit of the returned pkt, then
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* said NAL unit does not contain any emulation_prevention_three_byte and
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* the data is contained in the input buffer pointed to by buf.
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* Otherwise, the unescaped data is part of the rbsp_buffer described by the
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* packet's H2645RBSP.
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*
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* If the packet's rbsp_buffer_ref is not NULL, the underlying AVBuffer must
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* own rbsp_buffer. If not and rbsp_buffer is not NULL, use_ref must be 0.
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* If use_ref is set, rbsp_buffer will be reference-counted and owned by
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* the underlying AVBuffer of rbsp_buffer_ref.
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*/
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int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
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void *logctx, int is_nalff, int nal_length_size,
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enum AVCodecID codec_id, int small_padding, int use_ref);
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/**
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* Free all the allocated memory in the packet.
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*/
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void ff_h2645_packet_uninit(H2645Packet *pkt);
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static inline int get_nalsize(int nal_length_size, const uint8_t *buf,
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int buf_size, int *buf_index, void *logctx)
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{
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int i, nalsize = 0;
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if (*buf_index >= buf_size - nal_length_size) {
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// the end of the buffer is reached, refill it
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return AVERROR(EAGAIN);
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}
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for (i = 0; i < nal_length_size; i++)
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nalsize = ((unsigned)nalsize << 8) | buf[(*buf_index)++];
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if (nalsize <= 0 || nalsize > buf_size - *buf_index) {
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av_log(logctx, AV_LOG_ERROR,
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"Invalid NAL unit size (%d > %d).\n", nalsize, buf_size - *buf_index);
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return AVERROR_INVALIDDATA;
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}
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return nalsize;
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}
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#endif /* AVCODEC_H2645_PARSE_H */
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