[FFmpeg-trac] #11696(avformat:new): WAV ≥ 4 GiB abnormal decoding due to length field overflow

[FFmpeg]

#11696: WAV ≥ 4 GiB abnormal decoding due to length field overflow
----------------------------------+------------------------------------
             Reporter:  wavybaby  |                    Owner:  (none)
                 Type:  defect    |                   Status:  new
             Priority:  minor     |                Component:  avformat
              Version:  7.1       |               Resolution:
             Keywords:  wavdec    |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  1         |
----------------------------------+------------------------------------
Comment (by wavybaby):

 Replying to [comment:2 Marton Balint]:
 > You might want to try using the -ignore_length 1 option. In wav fiels
 the data chunk contains the wave data and it has a 32 bit length, so if
 your phone writes some random data there instead of UINT32_MAX, then that
 can limit the read audio.
 >
 > Alternatively you might want to upload here the first 64kb of some of
 your samples which are > 4GiB so we can check if there is a pattern which
 can be used to autodetect this...

 Good morning all, indeed `-ignore_length 1` resolves the issue:


 {{{
 $ ffmpeg -ignore_length 1 -i "2025-07-22 21.39.41.wav"
 2025-07-22_21.39.41.flac
 ffmpeg version n7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
   built with gcc 15.1.1 (GCC) 20250425
   configuration: --prefix=/usr --disable-debug --disable-static --disable-
 stripping --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto
 --enable-fontconfig --enable-frei0r --enable-gmp --enable-gnutls --enable-
 gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray
 --enable-libbs2b --enable-libdav1d --enable-libdrm --enable-libdvdnav
 --enable-libdvdread --enable-libfreetype --enable-libfribidi --enable-
 libglslang --enable-libgsm --enable-libharfbuzz --enable-libiec61883
 --enable-libjack --enable-libjxl --enable-libmodplug --enable-libmp3lame
 --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg
 --enable-libopenmpt --enable-libopus --enable-libplacebo --enable-libpulse
 --enable-librav1e --enable-librsvg --enable-librubberband --enable-
 libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-
 libssh --enable-libsvtav1 --enable-libtheora --enable-libv4l2 --enable-
 libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpl --enable-
 libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb
 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq
 --enable-nvdec --enable-nvenc --enable-opencl --enable-opengl --enable-
 shared --enable-vapoursynth --enable-version3 --enable-vulkan
   libavutil      59. 39.100 / 59. 39.100
   libavcodec     61. 19.101 / 61. 19.101
   libavformat    61.  7.100 / 61.  7.100
   libavdevice    61.  3.100 / 61.  3.100
   libavfilter    10.  4.100 / 10.  4.100
   libswscale      8.  3.100 /  8.  3.100
   libswresample   5.  3.100 /  5.  3.100
   libpostproc    58.  3.100 / 58.  3.100
 [aist#0:0/pcm_f32le @ 0x62ca6c2e0040] Guessed Channel Layout: stereo
 Input #0, wav, from '2025-07-22 21.39.41.wav':
   Duration: 00:37:51.04, bitrate: 21273 kb/s
   Stream #0:0: Audio: pcm_f32le ([3][0][0][0] / 0x0003), 96000 Hz, stereo,
 flt, 6144 kb/s
 File '2025-07-22_21.39.41.flac' already exists. Overwrite? [y/N] y
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_f32le (native) -> flac (native))
 Press [q] to stop, [?] for help
 [flac @ 0x62ca6c2d9900] encoding as 24 bits-per-sample, more is considered
 experimental. Add -strict experimental if you want to encode more than 24
 bits-per-sample
 Output #0, flac, to '2025-07-22_21.39.41.flac':
   Metadata:
     encoder         : Lavf61.7.100
   Stream #0:0: Audio: flac, 96000 Hz, stereo, s32 (24 bit), 128 kb/s
       Metadata:
         encoder         : Lavc61.19.101 flac
 [wav @ 0x62ca6c2d8c00] Packet corrupt (stream = 0, dts = NOPTS).30x
 [in#0/wav @ 0x62ca6c2d8940] corrupt input packet in stream 0
 [out#0/flac @ 0x62ca6c2e0200] video:0KiB audio:1292022KiB subtitle:0KiB
 other streams:0KiB global headers:0KiB muxing overhead: 0.000626%
 size= 1292030KiB time=02:11:03.45 bitrate=1346.0kbits/s speed= 297x


 }}}

 While my issue is resolved now, I imagine this might pose an issue in the
 future for others; thus, please feel free to close this ticket once or if
 any flags or changes are made :)

 Please let me know if a further sample or similar such thing is required,
 I can make another very very long recording on my phone :)

 Thank you again for the assistance to all!
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11696#comment:5>
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