ファイルを.at9から.oggに変換

次のファイルがいくつかあります。.at9ファイルは次のとおりです。

; file m330000001_0202fix.at9                                                   
m330000001_0202fix.at9: RIFF (little-endian) data, WAVE audio, 4 channels 48000 Hz   

私はffmpegそれをoggに変換しようとしましたが、次のエラーが発生しました。

; ffmpeg -i m330000001_0202fix.at9 m330000001_0202fix.ogg                       
ffmpeg version 3.3.6 Copyright (c) 2000-2017 the FFmpeg developers              
  built with gcc 7 (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 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m64 -mtune=generic' --extra-ldflags='-Wl,-z,relro -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags='-I/usr/include/nvenc ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libcdio --enable-indev=jack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect          
  libavutil      55. 58.100 / 55. 58.100                                        
  libavcodec     57. 89.100 / 57. 89.100                                        
  libavformat    57. 71.100 / 57. 71.100                                        
  libavdevice    57.  6.100 / 57.  6.100                                        
  libavfilter     6. 82.100 /  6. 82.100                                        
  libavresample   3.  5.  0 /  3.  5.  0                                        
  libswscale      4.  6.100 /  4.  6.100                                        
  libswresample   2.  7.100 /  2.  7.100                                        
  libpostproc    54.  5.100 / 54.  5.100                                        
[AVIOContext @ 0x55f4dd4344a0] unknown subformat:d242e147ba368d4d88fc61654f8c836c {47e142d2-36ba-4d8d-88fc-61654f8c836c}                                        
[wav @ 0x55f4dd42b720] Could not find codec parameters for stream 0 (Audio: none, 48000 Hz, 4 channels (FC), 72 kb/s): unknown codec                            
Consider increasing the value for the 'analyzeduration' and 'probesize' options 
Input #0, wav, from 'm330000001_0202fix.at9':                                   
  Duration: 00:01:24.01, bitrate: 240 kb/s                                      
    Stream #0:0: Audio: none, 48000 Hz, 4 channels (FC), 72 kb/s                
Stream mapping:     
  Stream #0:0 -> #0:0 (? (?) -> vorbis (libvorbis))                             
Decoder (codec none) not found for input stream #0:0          

私がここで何を見逃しているのでしょうか？