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/*
* H.264/HEVC common parsing code
*
* 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_H2645_PARSE_H
#define AVCODEC_H2645_PARSE_H
#include <stdint.h>
#include "libavutil/buffer.h"
#include "avcodec.h"
#include "get_bits.h"
#define MAX_MBPAIR_SIZE (256*1024) // a tighter bound could be calculated if someone cares about a few bytes
typedef struct H2645NAL {
uint8_t *rbsp_buffer;
int size;
const uint8_t *data;
/**
* Size, in bits, of just the data, excluding the stop bit and any trailing
* padding. I.e. what HEVC calls SODB.
*/
int size_bits;
int raw_size;
const uint8_t *raw_data;
GetBitContext gb;
/**
* NAL unit type
*/
int type;
/**
* HEVC only, nuh_temporal_id_plus_1 - 1
*/
int temporal_id;
/*
* HEVC only, identifier of layer to which nal unit belongs
*/
int nuh_layer_id;
int skipped_bytes;
int skipped_bytes_pos_size;
int *skipped_bytes_pos;
/**
* H.264 only, nal_ref_idc
*/
int ref_idc;
} H2645NAL;
typedef struct H2645RBSP {
uint8_t *rbsp_buffer;
AVBufferRef *rbsp_buffer_ref;
int rbsp_buffer_alloc_size;
int rbsp_buffer_size;
} H2645RBSP;
/* an input packet split into unescaped NAL units */
typedef struct H2645Packet {
H2645NAL *nals;
H2645RBSP rbsp;
int nb_nals;
int nals_allocated;
unsigned nal_buffer_size;
} H2645Packet;
/**
* Extract the raw (unescaped) bitstream.
*/
int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp,
H2645NAL *nal, int small_padding);
/**
* Split an input packet into NAL units.
*
* If data == raw_data holds true for a NAL unit of the returned pkt, then
* said NAL unit does not contain any emulation_prevention_three_byte and
* the data is contained in the input buffer pointed to by buf.
* Otherwise, the unescaped data is part of the rbsp_buffer described by the
* packet's H2645RBSP.
*
* If the packet's rbsp_buffer_ref is not NULL, the underlying AVBuffer must
* own rbsp_buffer. If not and rbsp_buffer is not NULL, use_ref must be 0.
* If use_ref is set, rbsp_buffer will be reference-counted and owned by
* the underlying AVBuffer of rbsp_buffer_ref.
*/
int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
void *logctx, int is_nalff, int nal_length_size,
enum AVCodecID codec_id, int small_padding, int use_ref);
/**
* Free all the allocated memory in the packet.
*/
void ff_h2645_packet_uninit(H2645Packet *pkt);
static inline int get_nalsize(int nal_length_size, const uint8_t *buf,
int buf_size, int *buf_index, void *logctx)
{
int i, nalsize = 0;
if (*buf_index >= buf_size - nal_length_size) {
// the end of the buffer is reached, refill it
return AVERROR(EAGAIN);
}
for (i = 0; i < nal_length_size; i++)
nalsize = ((unsigned)nalsize << 8) | buf[(*buf_index)++];
if (nalsize <= 0 || nalsize > buf_size - *buf_index) {
av_log(logctx, AV_LOG_ERROR,
"Invalid NAL unit size (%d > %d).\n", nalsize, buf_size - *buf_index);
return AVERROR_INVALIDDATA;
}
return nalsize;
}
#endif /* AVCODEC_H2645_PARSE_H */
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