"Reserved bit set" errors while decoding aac

[pszemus]

Summary of the bug:
How to reproduce:

$ ffmpeg -i 20221102_NEWSROOM_BRONOWICZ_ZAPORA.mp4 -f null -
ffmpeg version 5.0.1 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 12 (GCC)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 ' --extra-cflags=' -I/usr/include/rav1e' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --enable-chromaprint --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d --enable-libass --enable-libbluray --enable-libbs2b --enable-libcdio --enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libilbc --enable-libmp3lame --enable-libmysofa --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librav1e --enable-librubberband --enable-libsmbclient --enable-version3 --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-version3 --enable-vapoursynth --enable-libvpx --enable-vulkan --enable-libglslang --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libxml2 --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-avfilter --enable-libmodplug --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-lto --enable-libmfx --enable-runtime-cpudetect
  libavutil      57. 17.100 / 57. 17.100
  libavcodec     59. 18.100 / 59. 18.100
  libavformat    59. 16.100 / 59. 16.100
  libavdevice    59.  4.100 / 59.  4.100
  libavfilter     8. 24.100 /  8. 24.100
  libswscale      6.  4.100 /  6.  4.100
  libswresample   4.  3.100 /  4.  3.100
  libpostproc    56.  3.100 / 56.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20221102_NEWSROOM_BRONOWICZ_ZAPORA.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: avc1isommp42
    creation_time   : 2022-11-02T07:38:41.000000Z
  Duration: 00:00:58.37, start: 0.000000, bitrate: 9220 kb/s
  Stream #0:0[0x1](und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 8876 kb/s, 25 fps, 25 tbr, 90k tbn (default)
    Metadata:
      creation_time   : 2022-11-02T07:38:41.000000Z
      handler_name    : Apple Video Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : inegy Cinecoder H.264 Encoder
  Stream #0:1[0x2](und): Audio: aac (LTP) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 339 kb/s (default)
    Metadata:
      creation_time   : 2022-11-02T07:38:41.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> wrapped_avframe (native))
  Stream #0:1 -> #0:1 (aac (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: avc1isommp42
    encoder         : Lavf59.16.100
  Stream #0:0(und): Video: wrapped_avframe, yuv420p(top coded first (swapped)), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 25 tbn (default)
    Metadata:
      creation_time   : 2022-11-02T07:38:41.000000Z
      handler_name    : Apple Video Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : Lavc59.18.100 wrapped_avframe
  Stream #0:1(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2022-11-02T07:38:41.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : Lavc59.18.100 pcm_s16le
[aac @ 0x5556746778c0] Reserved bit set.=00:00:00.32 bitrate=N/A speed=8.05x    
    Last message repeated 9 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:11.58 bitrate=N/A speed=  11x    
    Last message repeated 1 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:17.83 bitrate=N/A speed=11.5x    
    Last message repeated 6 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:23.82 bitrate=N/A speed=11.6x    
    Last message repeated 1 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:29.67 bitrate=N/A speed=11.6x    
    Last message repeated 9 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:35.58 bitrate=N/A speed=11.6x    
    Last message repeated 14 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:41.74 bitrate=N/A speed=11.7x    
    Last message repeated 9 times
[aac @ 0x5556746778c0] Reserved bit set.=00:00:48.06 bitrate=N/A speed=11.8x    
    Last message repeated 15 times
frame= 1459 fps=326 q=-0.0 Lsize=N/A time=00:00:58.36 bitrate=N/A speed=  13x    
video:638kB audio:10944kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

Lots of "[aac @ 0x5556746778c0] Reserved bit set" errors but file proceeds correctly. Maybe they should be suppressed, silenced or downgraded to warnings?

[pszemus]

That happens with multiple files from the same source. One of them, used in "How to reproduce" section: ​https://drive.google.com/file/d/1sNnXWT0XMppDfIgTkPaETGg-LUIchgY6/view?usp=sharing

[Balling]

Anyone wants to find out what are the reserved bits that are set?

[MasterQuestionable]

͏    ​https://github.com/FFmpeg/FFmpeg/blob/2eab5a1f54cd08ea8b5a2b55a805718c51b26436/libavcodec/aac/aacdec.c#L1299
͏    ​https://github.com/FFmpeg/FFmpeg/blob/cf653aabb5b32ce2538365e32ea9db51592169c3/libavcodec/mpeg4audio.h#L108
͏    ​https://github.com/FFmpeg/FFmpeg/blob/4ab82d2fb6361864521b41a5c8168902e534fa1a/libavcodec/get_bits.h#L388-L406
͏    ​https://github.com/FFmpeg/FFmpeg/blob/8762aa4d62522f993a6f4b03902feb3e6a875b32/libavcodec/aac/aacdec_latm.h#L122-L200
͏    ​https://github.com/search?type=code&q=repo:FFmpeg/FFmpeg+path:/^libavcodec\/aac/+/(?-i)gb(?:%5CW|%24)/
͏    ​https://web.archive.org/web/20240519214054/http://www.telemidia.puc-rio.br/~rafaeldiniz/public_files/normas/ISO-13818/ISO_IEC_13818-7_2006(E).pdf#page=51 ("ics_reserved_bit")

[Balling]

Indeed, it is probably ics_reserved_bit, some printf debug can prove it. Still, I imagine such bitsream is just invalid.

[MasterQuestionable]

͏    Refer to:
͏    ​https://trac.ffmpeg.org/ticket/11020#comment:3