Invalid data found when processing input

[jsbjsb001]

Summary of the bug:
How to reproduce:

% ffmpeg -y -i "/multimedia1/Videos/temp/TheDissociatives-SomewhereDownTheBarrel.mpg" -acodec libmp3lame -vcodec msmpeg4 -b:a 192k -b:v 1000k -vf scale=640:480 -ar 44100 "/multimedia1/Videos/temp/TheDissociatives-SomewhereDownTheBarrel.avi"
ffmpeg version 2.8 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.8 (SUSE Linux)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --incdir=/usr/include/ffmpeg --extra-cflags='-fmessage-length=0 -grecord-gcc-switches -fstack-protector -O2 -Wall -D_FORTIFY_SOURCE=2 -funwind-tables -fasynchronous-unwind-tables' --optflags='-fmessage-length=0 -grecord-gcc-switches -fstack-protector -O2 -Wall -D_FORTIFY_SOURCE=2 -funwind-tables -fasynchronous-unwind-tables' --enable-pic --disable-stripping --enable-shared --disable-static --enable-runtime-cpudetect --enable-gpl --disable-openssl --enable-avresample --enable-frei0r --enable-gnutls --enable-libbluray --enable-libcdio --enable-libdc1394 --enable-libfreetype --enable-libgsm --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-pic --enable-pthreads --enable-vaapi --enable-vdpau --disable-encoders --disable-decoders --disable-muxers --disable-demuxers --enable-libschroedinger --enable-encoder=',012v,ansi,apng,bmp,flac,exr,ffv1,ffvhuff,gif,huffyuv,jpegls,libopenjpeg,libtheora,libvpx,pam,pbm,pcx,pgm,png,pgmyuv,ppm,sgi,sunrast,targa,tiff,v210,v308,v408,v410,webp,xbm,xwd,y41p,yuv4,celt,flac,ilbc,opus,pcm_alaw,pcm_bluray,pcm_dvd,pcm_f32be,pcm_f32le,pcm_f64be,pcm_f64le,pcm_mulaw,pcm_s16be,pcm_s16be_planer,pcm_s16le,pcm_s16le_planar,pcm_s24be,pcm_s24le,pcm_s24le_planar,pcm_s32be,pcm_s32le,pcm_s32le_planar,pcm_s8,pcm_s8_planar,pcm_u16be,pcm_u16le,pcm_u24be,pcm_u24le,pcm_u32be,pcm_u32le,pcm_u8,speex,libvorbis' --enable-decoder=',012v,ansi,apng,bmp,flac,exr,ffv1,ffvhuff,gif,huffyuv,jpegls,libopenjpeg,libtheora,libvpx,pam,pbm,pcx,pgm,png,pgmyuv,ppm,sgi,sunrast,targa,tiff,v210,v308,v408,v410,webp,xbm,xwd,y41p,yuv4,celt,flac,ilbc,opus,pcm_alaw,pcm_bluray,pcm_dvd,pcm_f32be,pcm_f32le,pcm_f64be,pcm_f64le,pcm_mulaw,pcm_s16be,pcm_s16be_planer,pcm_s16le,pcm_s16le_planar,pcm_s24be,pcm_s24le,pcm_s24le_planar,pcm_s32be,pcm_s32le,pcm_s32le_planar,pcm_s8,pcm_s8_planar,pcm_u16be,pcm_u16le,pcm_u24be,pcm_u24le,pcm_u32be,pcm_u32le,pcm_u8,speex,ljpeg,v210x,vorbis,vp3,vp5,vp6,vp6a,vp6f,vp8,vp9,otf,ttf,ass,srt,ssa,text' --enable-muxer='flac,gif,image2,image2pipe,matroska,matroska_audio,null,webm' --enable-demuxer='flac,gif,image2,image2pipe,matroska' --enable-x11grab
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
/multimedia1/Videos/temp/TheDissociatives-SomewhereDownTheBarrel.mpg: Invalid data found when processing input

[jsbjsb001]

The video file TheDissociatives-SomewhereDownTheBarrel.mpg is playable, but ffmpeg will not convert it to an avi file and gives the "Invalid data found when processing input" error.

[Hendrik]

Your ffmpeg is not compiled with .mpg support (--enable-demuxer='flac,gif,image2,image2pipe,matroska')

Please make sure you use a full build of ffmpeg with all relevant features enabled when reporting issues.