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FFmpeg/libavformat/vvcdec.c
Frank Plowman 7d7ba2175c libavformat/vvc: Make probe more conservative
Reduce false positives for VVC files by adding additional checks in
`vvc_probe`. Specifically, `nuh_temporal_id_plus1` is tested for valid
values in extra cases depending on the NAL unit type, as per ITU-T H.266
section 7.4.2.2.

Resolves trac #10703.

Signed-off-by: Frank Plowman <post@frankplowman.com>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
2023-12-19 19:44:38 +08:00

78 lines
2.3 KiB
C

/*
* RAW H.266 / VVC video demuxer
* Copyright (c) 2020 Nuo Mi <nuomi2021@gmail.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 "libavcodec/vvc.h"
#include "avformat.h"
#include "rawdec.h"
static int check_temporal_id(uint8_t nuh_temporal_id_plus1, int type)
{
if (nuh_temporal_id_plus1 == 0)
return 0;
if (nuh_temporal_id_plus1 != 1) {
if (type >= VVC_IDR_W_RADL && type <= VVC_RSV_IRAP_11
|| type == VVC_DCI_NUT || type == VVC_OPI_NUT
|| type == VVC_VPS_NUT || type == VVC_SPS_NUT
|| type == VVC_EOS_NUT || type == VVC_EOB_NUT)
return 0;
}
return 1;
}
static int vvc_probe(const AVProbeData *p)
{
uint32_t code = -1;
int sps = 0, pps = 0, irap = 0;
int i;
for (i = 0; i < p->buf_size - 1; i++) {
code = (code << 8) + p->buf[i];
if ((code & 0xffffff00) == 0x100) {
uint8_t nal2 = p->buf[i + 1];
int type = (nal2 & 0xF8) >> 3;
if (code & 0x80) // forbidden_zero_bit
return 0;
if (!check_temporal_id(nal2 & 0x7, type))
return 0;
switch (type) {
case VVC_SPS_NUT: sps++; break;
case VVC_PPS_NUT: pps++; break;
case VVC_IDR_N_LP:
case VVC_IDR_W_RADL:
case VVC_CRA_NUT:
case VVC_GDR_NUT: irap++; break;
}
}
}
if (sps && pps && irap)
return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg
return 0;
}
FF_DEF_RAWVIDEO_DEMUXER(vvc, "raw H.266/VVC video", vvc_probe, "h266,266,vvc", AV_CODEC_ID_VVC)