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FFmpeg/libavcodec/h2645_parse.c
Mattias Wadman 78812cd147 avcodec/h2645_parse: Don't treat 0x000002 as a start code and truncate
According to ITU-T H.265 7.4.2.1 this byte sequence should not appear in a
NAL unit but in practice in rare cases it seems it does, possibly due to buggy
encoders. Other players like VLC and Quicktime seem to be fine with it.

Currently when this sequence is found it is treated as if the next start code
has been found and the NAL unit gets truncated.

This change limits the code to only look for first start code 0x0000001 or
first escape 0x000003.

Sadly i can't share the original source file with the issue but the first
80 bytes of the NAL unit looks like this:

       │00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f│0123456789abcdef│
0x00000│00 00 00 01 02 01 d0 bc 57 a1 b8 44 70 01 00 0b│........W..Dp...│
0x00010│80 2e 00 c2 6c ec 3e b9 e3 03 fb 91 2e d2 43 cb│....l.>.......C.│
0x00020│1d 2c 00 00 02 00 02 00 5c 93 72 6f 31 76 18 00│.,......\.ro1v..│
0x00030│08 38 aa b1 4c 33 3f fd 08 cb 77 9b d4 3c db 02│.8..L3?...w..<..│
0x00040│a2 04 73 15 75 de 3b c4 67 c0 8f ca ad 31 f1 99│..s.u.;.g....1..│

Signed-off-by: Anton Khirnov <anton@khirnov.net>
2024-02-18 07:33:27 +01:00

613 lines
19 KiB
C

/*
* 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
*/
#include <string.h>
#include "config.h"
#include "libavutil/intmath.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "bytestream.h"
#include "hevc.h"
#include "h264.h"
#include "h2645_parse.h"
#include "vvc.h"
int ff_h2645_extract_rbsp(const uint8_t *src, int length,
H2645RBSP *rbsp, H2645NAL *nal, int small_padding)
{
int i, si, di;
uint8_t *dst;
nal->skipped_bytes = 0;
#define STARTCODE_TEST \
if (i + 2 < length && src[i + 1] == 0 && \
(src[i + 2] == 3 || src[i + 2] == 1)) { \
if (src[i + 2] == 1) { \
/* startcode, so we must be past the end */ \
length = i; \
} \
break; \
}
#if HAVE_FAST_UNALIGNED
#define FIND_FIRST_ZERO \
if (i > 0 && !src[i]) \
i--; \
while (src[i]) \
i++
#if HAVE_FAST_64BIT
for (i = 0; i + 1 < length; i += 9) {
if (!((~AV_RN64(src + i) &
(AV_RN64(src + i) - 0x0100010001000101ULL)) &
0x8000800080008080ULL))
continue;
FIND_FIRST_ZERO;
STARTCODE_TEST;
i -= 7;
}
#else
for (i = 0; i + 1 < length; i += 5) {
if (!((~AV_RN32(src + i) &
(AV_RN32(src + i) - 0x01000101U)) &
0x80008080U))
continue;
FIND_FIRST_ZERO;
STARTCODE_TEST;
i -= 3;
}
#endif /* HAVE_FAST_64BIT */
#else
for (i = 0; i + 1 < length; i += 2) {
if (src[i])
continue;
if (i > 0 && src[i - 1] == 0)
i--;
STARTCODE_TEST;
}
#endif /* HAVE_FAST_UNALIGNED */
if (i >= length - 1 && small_padding) { // no escaped 0
nal->data =
nal->raw_data = src;
nal->size =
nal->raw_size = length;
return length;
} else if (i > length)
i = length;
dst = &rbsp->rbsp_buffer[rbsp->rbsp_buffer_size];
memcpy(dst, src, i);
si = di = i;
while (si + 2 < length) {
// remove escapes (very rare 1:2^22)
if (src[si + 2] > 3) {
dst[di++] = src[si++];
dst[di++] = src[si++];
} else if (src[si] == 0 && src[si + 1] == 0 && src[si + 2] != 0) {
if (src[si + 2] == 3) { // escape
dst[di++] = 0;
dst[di++] = 0;
si += 3;
if (nal->skipped_bytes_pos) {
nal->skipped_bytes++;
if (nal->skipped_bytes_pos_size < nal->skipped_bytes) {
nal->skipped_bytes_pos_size *= 2;
av_assert0(nal->skipped_bytes_pos_size >= nal->skipped_bytes);
av_reallocp_array(&nal->skipped_bytes_pos,
nal->skipped_bytes_pos_size,
sizeof(*nal->skipped_bytes_pos));
if (!nal->skipped_bytes_pos) {
nal->skipped_bytes_pos_size = 0;
return AVERROR(ENOMEM);
}
}
if (nal->skipped_bytes_pos)
nal->skipped_bytes_pos[nal->skipped_bytes-1] = di - 1;
}
continue;
} else // next start code
goto nsc;
}
dst[di++] = src[si++];
}
while (si < length)
dst[di++] = src[si++];
nsc:
memset(dst + di, 0, AV_INPUT_BUFFER_PADDING_SIZE);
nal->data = dst;
nal->size = di;
nal->raw_data = src;
nal->raw_size = si;
rbsp->rbsp_buffer_size += si;
return si;
}
static const char *const vvc_nal_type_name[32] = {
"TRAIL_NUT", // VVC_TRAIL_NUT
"STSA_NUT", // VVC_STSA_NUT
"RADL_NUT", // VVC_RADL_NUT
"RASL_NUT", // VVC_RASL_NUT
"RSV_VCL4", // VVC_RSV_VCL_4
"RSV_VCL5", // VVC_RSV_VCL_5
"RSV_VCL6", // VVC_RSV_VCL_6
"IDR_W_RADL", // VVC_IDR_W_RADL
"IDR_N_LP", // VVC_IDR_N_LP
"CRA_NUT", // VVC_CRA_NUT
"GDR_NUT", // VVC_GDR_NUT
"RSV_IRAP_11", // VVC_RSV_IRAP_11
"OPI_NUT", // VVC_OPI_NUT
"DCI_NUT", // VVC_DCI_NUT
"VPS_NUT", // VVC_VPS_NUT
"SPS_NUT", // VVC_SPS_NUT
"PPS_NUT", // VVC_PPS_NUT
"APS_PREFIX", // VVC_PREFIX_APS_NUT
"APS_SUFFIX", // VVC_SUFFIX_APS_NUT
"PH_NUT", // VVC_PH_NUT
"AUD_NUT", // VVC_AUD_NUT
"EOS_NUT", // VVC_EOS_NUT
"EOB_NUT", // VVC_EOB_NUT
"SEI_PREFIX", // VVC_PREFIX_SEI_NUT
"SEI_SUFFIX", // VVC_SUFFIX_SEI_NUT
"FD_NUT", // VVC_FD_NUT
"RSV_NVCL26", // VVC_RSV_NVCL_26
"RSV_NVCL27", // VVC_RSV_NVCL_27
"UNSPEC28", // VVC_UNSPEC_28
"UNSPEC29", // VVC_UNSPEC_29
"UNSPEC30", // VVC_UNSPEC_30
"UNSPEC31", // VVC_UNSPEC_31
};
static const char *vvc_nal_unit_name(int nal_type)
{
av_assert0(nal_type >= 0 && nal_type < 32);
return vvc_nal_type_name[nal_type];
}
static const char *const hevc_nal_type_name[64] = {
"TRAIL_N", // HEVC_NAL_TRAIL_N
"TRAIL_R", // HEVC_NAL_TRAIL_R
"TSA_N", // HEVC_NAL_TSA_N
"TSA_R", // HEVC_NAL_TSA_R
"STSA_N", // HEVC_NAL_STSA_N
"STSA_R", // HEVC_NAL_STSA_R
"RADL_N", // HEVC_NAL_RADL_N
"RADL_R", // HEVC_NAL_RADL_R
"RASL_N", // HEVC_NAL_RASL_N
"RASL_R", // HEVC_NAL_RASL_R
"RSV_VCL_N10", // HEVC_NAL_VCL_N10
"RSV_VCL_R11", // HEVC_NAL_VCL_R11
"RSV_VCL_N12", // HEVC_NAL_VCL_N12
"RSV_VLC_R13", // HEVC_NAL_VCL_R13
"RSV_VCL_N14", // HEVC_NAL_VCL_N14
"RSV_VCL_R15", // HEVC_NAL_VCL_R15
"BLA_W_LP", // HEVC_NAL_BLA_W_LP
"BLA_W_RADL", // HEVC_NAL_BLA_W_RADL
"BLA_N_LP", // HEVC_NAL_BLA_N_LP
"IDR_W_RADL", // HEVC_NAL_IDR_W_RADL
"IDR_N_LP", // HEVC_NAL_IDR_N_LP
"CRA_NUT", // HEVC_NAL_CRA_NUT
"RSV_IRAP_VCL22", // HEVC_NAL_RSV_IRAP_VCL22
"RSV_IRAP_VCL23", // HEVC_NAL_RSV_IRAP_VCL23
"RSV_VCL24", // HEVC_NAL_RSV_VCL24
"RSV_VCL25", // HEVC_NAL_RSV_VCL25
"RSV_VCL26", // HEVC_NAL_RSV_VCL26
"RSV_VCL27", // HEVC_NAL_RSV_VCL27
"RSV_VCL28", // HEVC_NAL_RSV_VCL28
"RSV_VCL29", // HEVC_NAL_RSV_VCL29
"RSV_VCL30", // HEVC_NAL_RSV_VCL30
"RSV_VCL31", // HEVC_NAL_RSV_VCL31
"VPS", // HEVC_NAL_VPS
"SPS", // HEVC_NAL_SPS
"PPS", // HEVC_NAL_PPS
"AUD", // HEVC_NAL_AUD
"EOS_NUT", // HEVC_NAL_EOS_NUT
"EOB_NUT", // HEVC_NAL_EOB_NUT
"FD_NUT", // HEVC_NAL_FD_NUT
"SEI_PREFIX", // HEVC_NAL_SEI_PREFIX
"SEI_SUFFIX", // HEVC_NAL_SEI_SUFFIX
"RSV_NVCL41", // HEVC_NAL_RSV_NVCL41
"RSV_NVCL42", // HEVC_NAL_RSV_NVCL42
"RSV_NVCL43", // HEVC_NAL_RSV_NVCL43
"RSV_NVCL44", // HEVC_NAL_RSV_NVCL44
"RSV_NVCL45", // HEVC_NAL_RSV_NVCL45
"RSV_NVCL46", // HEVC_NAL_RSV_NVCL46
"RSV_NVCL47", // HEVC_NAL_RSV_NVCL47
"UNSPEC48", // HEVC_NAL_UNSPEC48
"UNSPEC49", // HEVC_NAL_UNSPEC49
"UNSPEC50", // HEVC_NAL_UNSPEC50
"UNSPEC51", // HEVC_NAL_UNSPEC51
"UNSPEC52", // HEVC_NAL_UNSPEC52
"UNSPEC53", // HEVC_NAL_UNSPEC53
"UNSPEC54", // HEVC_NAL_UNSPEC54
"UNSPEC55", // HEVC_NAL_UNSPEC55
"UNSPEC56", // HEVC_NAL_UNSPEC56
"UNSPEC57", // HEVC_NAL_UNSPEC57
"UNSPEC58", // HEVC_NAL_UNSPEC58
"UNSPEC59", // HEVC_NAL_UNSPEC59
"UNSPEC60", // HEVC_NAL_UNSPEC60
"UNSPEC61", // HEVC_NAL_UNSPEC61
"UNSPEC62", // HEVC_NAL_UNSPEC62
"UNSPEC63", // HEVC_NAL_UNSPEC63
};
static const char *hevc_nal_unit_name(int nal_type)
{
av_assert0(nal_type >= 0 && nal_type < 64);
return hevc_nal_type_name[nal_type];
}
static const char *const h264_nal_type_name[32] = {
"Unspecified 0", //H264_NAL_UNSPECIFIED
"Coded slice of a non-IDR picture", // H264_NAL_SLICE
"Coded slice data partition A", // H264_NAL_DPA
"Coded slice data partition B", // H264_NAL_DPB
"Coded slice data partition C", // H264_NAL_DPC
"IDR", // H264_NAL_IDR_SLICE
"SEI", // H264_NAL_SEI
"SPS", // H264_NAL_SPS
"PPS", // H264_NAL_PPS
"AUD", // H264_NAL_AUD
"End of sequence", // H264_NAL_END_SEQUENCE
"End of stream", // H264_NAL_END_STREAM
"Filler data", // H264_NAL_FILLER_DATA
"SPS extension", // H264_NAL_SPS_EXT
"Prefix", // H264_NAL_PREFIX
"Subset SPS", // H264_NAL_SUB_SPS
"Depth parameter set", // H264_NAL_DPS
"Reserved 17", // H264_NAL_RESERVED17
"Reserved 18", // H264_NAL_RESERVED18
"Auxiliary coded picture without partitioning", // H264_NAL_AUXILIARY_SLICE
"Slice extension", // H264_NAL_EXTEN_SLICE
"Slice extension for a depth view or a 3D-AVC texture view", // H264_NAL_DEPTH_EXTEN_SLICE
"Reserved 22", // H264_NAL_RESERVED22
"Reserved 23", // H264_NAL_RESERVED23
"Unspecified 24", // H264_NAL_UNSPECIFIED24
"Unspecified 25", // H264_NAL_UNSPECIFIED25
"Unspecified 26", // H264_NAL_UNSPECIFIED26
"Unspecified 27", // H264_NAL_UNSPECIFIED27
"Unspecified 28", // H264_NAL_UNSPECIFIED28
"Unspecified 29", // H264_NAL_UNSPECIFIED29
"Unspecified 30", // H264_NAL_UNSPECIFIED30
"Unspecified 31", // H264_NAL_UNSPECIFIED31
};
static const char *h264_nal_unit_name(int nal_type)
{
av_assert0(nal_type >= 0 && nal_type < 32);
return h264_nal_type_name[nal_type];
}
static int get_bit_length(H2645NAL *nal, int min_size, int skip_trailing_zeros)
{
int size = nal->size;
int trailing_padding = 0;
while (skip_trailing_zeros && size > 0 && nal->data[size - 1] == 0)
size--;
if (!size)
return 0;
if (size <= min_size) {
if (nal->size < min_size)
return AVERROR_INVALIDDATA;
size = min_size;
} else {
int v = nal->data[size - 1];
/* remove the stop bit and following trailing zeros,
* or nothing for damaged bitstreams */
if (v)
trailing_padding = ff_ctz(v) + 1;
}
if (size > INT_MAX / 8)
return AVERROR(ERANGE);
size *= 8;
return size - trailing_padding;
}
/**
* @return AVERROR_INVALIDDATA if the packet is not a valid NAL unit,
* 0 otherwise
*/
static int vvc_parse_nal_header(H2645NAL *nal, void *logctx)
{
GetBitContext *gb = &nal->gb;
if (get_bits1(gb) != 0) //forbidden_zero_bit
return AVERROR_INVALIDDATA;
skip_bits1(gb); //nuh_reserved_zero_bit
nal->nuh_layer_id = get_bits(gb, 6);
nal->type = get_bits(gb, 5);
nal->temporal_id = get_bits(gb, 3) - 1;
if (nal->temporal_id < 0)
return AVERROR_INVALIDDATA;
if ((nal->type >= VVC_IDR_W_RADL && nal->type <= VVC_RSV_IRAP_11) && nal->temporal_id)
return AVERROR_INVALIDDATA;
av_log(logctx, AV_LOG_DEBUG,
"nal_unit_type: %d(%s), nuh_layer_id: %d, temporal_id: %d\n",
nal->type, vvc_nal_unit_name(nal->type), nal->nuh_layer_id, nal->temporal_id);
return 0;
}
static int hevc_parse_nal_header(H2645NAL *nal, void *logctx)
{
GetBitContext *gb = &nal->gb;
if (get_bits1(gb) != 0)
return AVERROR_INVALIDDATA;
nal->type = get_bits(gb, 6);
nal->nuh_layer_id = get_bits(gb, 6);
nal->temporal_id = get_bits(gb, 3) - 1;
if (nal->temporal_id < 0)
return AVERROR_INVALIDDATA;
av_log(logctx, AV_LOG_DEBUG,
"nal_unit_type: %d(%s), nuh_layer_id: %d, temporal_id: %d\n",
nal->type, hevc_nal_unit_name(nal->type), nal->nuh_layer_id, nal->temporal_id);
return 0;
}
static int h264_parse_nal_header(H2645NAL *nal, void *logctx)
{
GetBitContext *gb = &nal->gb;
if (get_bits1(gb) != 0)
return AVERROR_INVALIDDATA;
nal->ref_idc = get_bits(gb, 2);
nal->type = get_bits(gb, 5);
av_log(logctx, AV_LOG_DEBUG,
"nal_unit_type: %d(%s), nal_ref_idc: %d\n",
nal->type, h264_nal_unit_name(nal->type), nal->ref_idc);
return 0;
}
static int find_next_start_code(const uint8_t *buf, const uint8_t *next_avc)
{
int i = 0;
if (buf + 3 >= next_avc)
return next_avc - buf;
while (buf + i + 3 < next_avc) {
if (buf[i] == 0 && buf[i + 1] == 0 && buf[i + 2] == 1)
break;
i++;
}
return i + 3;
}
static void alloc_rbsp_buffer(H2645RBSP *rbsp, unsigned int size, int use_ref)
{
int min_size = size;
if (size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
goto fail;
size += AV_INPUT_BUFFER_PADDING_SIZE;
if (rbsp->rbsp_buffer_alloc_size >= size &&
(!rbsp->rbsp_buffer_ref || av_buffer_is_writable(rbsp->rbsp_buffer_ref))) {
av_assert0(rbsp->rbsp_buffer);
memset(rbsp->rbsp_buffer + min_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
return;
}
size = FFMIN(size + size / 16 + 32, INT_MAX);
if (rbsp->rbsp_buffer_ref)
av_buffer_unref(&rbsp->rbsp_buffer_ref);
else
av_free(rbsp->rbsp_buffer);
rbsp->rbsp_buffer = av_mallocz(size);
if (!rbsp->rbsp_buffer)
goto fail;
rbsp->rbsp_buffer_alloc_size = size;
if (use_ref) {
rbsp->rbsp_buffer_ref = av_buffer_create(rbsp->rbsp_buffer, size,
NULL, NULL, 0);
if (!rbsp->rbsp_buffer_ref)
goto fail;
}
return;
fail:
rbsp->rbsp_buffer_alloc_size = 0;
if (rbsp->rbsp_buffer_ref) {
av_buffer_unref(&rbsp->rbsp_buffer_ref);
rbsp->rbsp_buffer = NULL;
} else
av_freep(&rbsp->rbsp_buffer);
return;
}
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)
{
GetByteContext bc;
int consumed, ret = 0;
int next_avc = is_nalff ? 0 : length;
int64_t padding = small_padding ? 0 : MAX_MBPAIR_SIZE;
bytestream2_init(&bc, buf, length);
alloc_rbsp_buffer(&pkt->rbsp, length + padding, use_ref);
if (!pkt->rbsp.rbsp_buffer)
return AVERROR(ENOMEM);
pkt->rbsp.rbsp_buffer_size = 0;
pkt->nb_nals = 0;
while (bytestream2_get_bytes_left(&bc) >= 4) {
H2645NAL *nal;
int extract_length = 0;
int skip_trailing_zeros = 1;
if (bytestream2_tell(&bc) == next_avc) {
int i = 0;
extract_length = get_nalsize(nal_length_size,
bc.buffer, bytestream2_get_bytes_left(&bc), &i, logctx);
if (extract_length < 0)
return extract_length;
bytestream2_skip(&bc, nal_length_size);
next_avc = bytestream2_tell(&bc) + extract_length;
} else {
int buf_index;
if (bytestream2_tell(&bc) > next_avc)
av_log(logctx, AV_LOG_WARNING, "Exceeded next NALFF position, re-syncing.\n");
/* search start code */
buf_index = find_next_start_code(bc.buffer, buf + next_avc);
bytestream2_skip(&bc, buf_index);
if (!bytestream2_get_bytes_left(&bc)) {
if (pkt->nb_nals > 0) {
// No more start codes: we discarded some irrelevant
// bytes at the end of the packet.
return 0;
} else {
av_log(logctx, AV_LOG_ERROR, "No start code is found.\n");
return AVERROR_INVALIDDATA;
}
}
extract_length = FFMIN(bytestream2_get_bytes_left(&bc), next_avc - bytestream2_tell(&bc));
if (bytestream2_tell(&bc) >= next_avc) {
/* skip to the start of the next NAL */
bytestream2_skip(&bc, next_avc - bytestream2_tell(&bc));
continue;
}
}
if (pkt->nals_allocated < pkt->nb_nals + 1) {
int new_size = pkt->nals_allocated + 1;
void *tmp;
if (new_size >= INT_MAX / sizeof(*pkt->nals))
return AVERROR(ENOMEM);
tmp = av_fast_realloc(pkt->nals, &pkt->nal_buffer_size, new_size * sizeof(*pkt->nals));
if (!tmp)
return AVERROR(ENOMEM);
pkt->nals = tmp;
memset(pkt->nals + pkt->nals_allocated, 0, sizeof(*pkt->nals));
nal = &pkt->nals[pkt->nb_nals];
nal->skipped_bytes_pos_size = FFMIN(1024, extract_length/3+1); // initial buffer size
nal->skipped_bytes_pos = av_malloc_array(nal->skipped_bytes_pos_size, sizeof(*nal->skipped_bytes_pos));
if (!nal->skipped_bytes_pos)
return AVERROR(ENOMEM);
pkt->nals_allocated = new_size;
}
nal = &pkt->nals[pkt->nb_nals];
consumed = ff_h2645_extract_rbsp(bc.buffer, extract_length, &pkt->rbsp, nal, small_padding);
if (consumed < 0)
return consumed;
if (is_nalff && (extract_length != consumed) && extract_length)
av_log(logctx, AV_LOG_DEBUG,
"NALFF: Consumed only %d bytes instead of %d\n",
consumed, extract_length);
bytestream2_skip(&bc, consumed);
/* see commit 3566042a0 */
if (bytestream2_get_bytes_left(&bc) >= 4 &&
bytestream2_peek_be32(&bc) == 0x000001E0)
skip_trailing_zeros = 0;
nal->size_bits = get_bit_length(nal, 1 + (codec_id == AV_CODEC_ID_HEVC),
skip_trailing_zeros);
if (nal->size <= 0 || nal->size_bits <= 0)
continue;
ret = init_get_bits(&nal->gb, nal->data, nal->size_bits);
if (ret < 0)
return ret;
/* Reset type in case it contains a stale value from a previously parsed NAL */
nal->type = 0;
if (codec_id == AV_CODEC_ID_VVC)
ret = vvc_parse_nal_header(nal, logctx);
else if (codec_id == AV_CODEC_ID_HEVC)
ret = hevc_parse_nal_header(nal, logctx);
else
ret = h264_parse_nal_header(nal, logctx);
if (ret < 0) {
av_log(logctx, AV_LOG_WARNING, "Invalid NAL unit %d, skipping.\n",
nal->type);
continue;
}
pkt->nb_nals++;
}
return 0;
}
void ff_h2645_packet_uninit(H2645Packet *pkt)
{
int i;
for (i = 0; i < pkt->nals_allocated; i++) {
av_freep(&pkt->nals[i].skipped_bytes_pos);
}
av_freep(&pkt->nals);
pkt->nals_allocated = pkt->nal_buffer_size = 0;
if (pkt->rbsp.rbsp_buffer_ref) {
av_buffer_unref(&pkt->rbsp.rbsp_buffer_ref);
pkt->rbsp.rbsp_buffer = NULL;
} else
av_freep(&pkt->rbsp.rbsp_buffer);
pkt->rbsp.rbsp_buffer_alloc_size = pkt->rbsp.rbsp_buffer_size = 0;
}