Bug Summary

File:root/firefox-clang/media/ffvpx/libavcodec/vp9_parser.c
Warning:line 39, column 19
Although the value stored to 'res' is used in the enclosing expression, the value is never actually read from 'res'

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -O2 -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name vp9_parser.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -ffp-contract=off -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavcodec -fcoverage-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavcodec -resource-dir /usr/lib/llvm-23/lib/clang/23 -include /root/firefox-clang/obj-x86_64-pc-linux-gnu/mozilla-config.h -include libavutil_visibility.h -U _FORTIFY_SOURCE -D _FORTIFY_SOURCE=2 -D DEBUG=1 -D HAVE_AV_CONFIG_H -D ASSERT_LEVEL=2 -I /root/firefox-clang/media/ffvpx/libavcodec -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/media/ffvpx/libavcodec -I /root/firefox-clang/modules/fdlibm/inexact-math-override -I /root/firefox-clang/third_party/khronos/vulkan-headers/include -I /root/firefox-clang/media/mozva -I /root/firefox-clang/media/libopus/include -I /root/firefox-clang/media/libvorbis -I /root/firefox-clang/media/libvpx -I /root/firefox-clang/media/ffvpx -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nspr -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nss -D MOZILLA_CLIENT -internal-isystem /usr/lib/llvm-23/lib/clang/23/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/16/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wno-error=tautological-type-limit-compare -Wno-range-loop-analysis -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=free-nonheap-object -Wno-error=atomic-alignment -Wno-error=deprecated-builtins -Wno-psabi -Wno-error=builtin-macro-redefined -Wno-unknown-warning-option -Wno-character-conversion -Wno-parentheses -Wno-pointer-sign -Wno-sign-compare -Wno-switch -Wno-type-limits -Wno-unused-function -Wno-deprecated-declarations -Wno-absolute-value -Wno-incompatible-pointer-types -Wno-string-conversion -Wno-visibility -ferror-limit 19 -fstrict-flex-arrays=1 -stack-protector 2 -fstack-clash-protection -ftrivial-auto-var-init=pattern -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fdiagnostics-absolute-paths -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -mllvm -dwarf-linkage-names=Abstract -faddrsig -fdwarf2-cfi-asm -o /tmp/scan-build-2026-09-01-224014-2642839-1 -x c /root/firefox-clang/media/ffvpx/libavcodec/vp9_parser.c
1/*
2 * VP9 compatible video decoder
3 *
4 * Copyright (C) 2013 Ronald S. Bultje <rsbultje gmail com>
5 * Copyright (C) 2013 Clément Bœsch <u pkh me>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include "avcodec.h"
25#include "get_bits.h"
26#include "parser_internal.h"
27
28static int parse(AVCodecParserContext *ctx,
29 AVCodecContext *avctx,
30 const uint8_t **out_data, int *out_size,
31 const uint8_t *data, int size)
32{
33 GetBitContext gb;
34 int res, profile, keyframe;
35
36 *out_data = data;
37 *out_size = size;
38
39 if (!size || (res = init_get_bits8(&gb, data, size)) < 0)
Although the value stored to 'res' is used in the enclosing expression, the value is never actually read from 'res'
40 return size; // parsers can't return errors
41 get_bits(&gb, 2); // frame marker
42 profile = get_bits1(&gb);
43 profile |= get_bits1(&gb) << 1;
44 if (profile == 3) profile += get_bits1(&gb);
45 if (profile > 3)
46 return size;
47
48 avctx->profile = profile;
49
50 if (get_bits1(&gb)) {
51 keyframe = 0;
52 } else {
53 keyframe = !get_bits1(&gb);
54 }
55
56 if (!keyframe) {
57 ctx->pict_type = AV_PICTURE_TYPE_P;
58 ctx->key_frame = 0;
59 } else {
60 ctx->pict_type = AV_PICTURE_TYPE_I;
61 ctx->key_frame = 1;
62 }
63
64 return size;
65}
66
67const FFCodecParser ff_vp9_parser = {
68 PARSER_CODEC_LIST(AV_CODEC_ID_VP9).codec_ids = { AV_CODEC_ID_VP9,AV_CODEC_ID_NONE,AV_CODEC_ID_NONE
,AV_CODEC_ID_NONE,AV_CODEC_ID_NONE,AV_CODEC_ID_NONE,AV_CODEC_ID_NONE
}
,
69 .parse = parse,
70};