animated webp cannot be processed by ffmpeg or ffplay

[rabcor]

ffmpeg fails to read animated webp files. (Sample File: ​https://mathiasbynens.be/demo/animated-webp-supported.webp)

Gives errors:

[webp @ 0x7b87000020c0] skipping unsupported chunk: ANIM 0B 
[webp @ 0x7b87000020c0] skipping unsupported chunk: ANMF
[webp @ 0x7b87000020c0] image data not found

How to reproduce:

ffplay any-animated.webp
#or
ffmpeg -i any-animated.webp output.anyformat

Other Info:

ffmpeg -version:

ffmpeg version N-114897-gbba996d6cd Copyright (c) 2000-2024 the FFmpeg developers
built with gcc 13.2.1 (GCC) 20230801
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --disable-htmlpages --enable-amf --enable-avisynth --enable-cuda-llvm --enable-lto --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libjxl --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librav1e --enable-librsvg --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-nvdec --enable-nvenc --enable-opencl --enable-opengl --enable-shared --enable-version3 --enable-vulkan
libavutil      59. 15.100 / 59. 15.100
libavcodec     61.  5.103 / 61.  5.103
libavformat    61.  3.100 / 61.  3.100
libavdevice    61.  2.100 / 61.  2.100
libavfilter    10.  2.101 / 10.  2.101
libswscale      8.  2.100 /  8.  2.100
libswresample   5.  2.100 /  5.  2.100
libpostproc    58.  2.100 / 58.  2.100

ffmpeg -v 9 -loglevel 99 -i animated-webp-supported.webp:

Splitting the commandline.
Reading option '-v' ... matched as option 'v' (set logging level) with argument '9'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument '99'.
Reading option '-i' ... matched as input url with argument 'animated-webp-supported.webp'.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument 9.
Successfully parsed a group of options.
Parsing a group of options: input url animated-webp-supported.webp.
Successfully parsed a group of options.
Opening an input file: animated-webp-supported.webp.
[AVFormatContext @ 0x59fb643aa980] Opening 'animated-webp-supported.webp' for reading
[file @ 0x59fb6436bb40] Setting default whitelist 'file,crypto,data'
Probing image2 score:50 size:2048
Probing mp3 score:1 size:2048
Probing webp_pipe score:99 size:2048
[webp_pipe @ 0x59fb643aa980] Format webp_pipe probed with size=2048 and score=99
[webp_pipe @ 0x59fb643aa980] Before avformat_find_stream_info() pos: 0 bytes read:32768 seeks:0 nb_streams:1
[webp @ 0x59fb643abb40] skipping unsupported chunk: ANIM
[webp @ 0x59fb643abb40] skipping unsupported chunk: ANMF
    Last message repeated 11 times
[webp @ 0x59fb643abb40] image data not found
[webp_pipe @ 0x59fb643aa980] stream 0: start_time: NOPTS duration: NOPTS
[webp_pipe @ 0x59fb643aa980] format: start_time: NOPTS duration: NOPTS (estimate from bit rate) bitrate=0 kb/s
[webp_pipe @ 0x59fb643aa980] Could not find codec parameters for stream 0 (Video: webp, 1 reference frame, none): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
[webp_pipe @ 0x59fb643aa980] After avformat_find_stream_info() pos: 37342 bytes read:37342 seeks:0 frames:1
Input #0, webp_pipe, from 'animated-webp-supported.webp':
  Duration: N/A, bitrate: N/A
  Stream #0:0, 1, 1/25: Video: webp, 1 reference frame, none, 25 fps, 25 tbr, 25 tbn
Successfully opened the file.
At least one output file must be specified
[AVIOContext @ 0x59fb643b3000] Statistics: 37342 bytes read, 0 seeks

[rabcor]

alternate sample file

[mkver]

Duplicate of #4907.