Анализ ELF символов кое-что проясняет.

at@solemn ~/.qa-robot/rpmelfsym 7 $ grep SDL_ConvertSurround dump.old
libSDL  /usr/lib/libSDL-1.2.so.0.7.1    T       SDL_ConvertSurround
libSDL  /usr/lib/libSDL-1.2.so.0.7.1    T       SDL_ConvertSurround_4
libmpeg4ip      /usr/lib/libmpeg4ipSDL-1.2.so.0.7.1     T       SDL_ConvertSurround
libmpeg4ip      /usr/lib/libmpeg4ipSDL-1.2.so.0.7.1     T       SDL_ConvertSurround_4
at@solemn ~/.qa-robot/rpmelfsym 7 $

[at@basalt mpeg4ip-1.3]$ find lib/SDLAudio -name '*.c'
lib/SDLAudio/src/audio/dc/SDL_dcaudio.c
lib/SDLAudio/src/audio/dc/aica.c
lib/SDLAudio/src/audio/dma/SDL_dmaaudio.c
lib/SDLAudio/src/audio/dsp/SDL_dspaudio.c
lib/SDLAudio/src/audio/esd/SDL_esdaudio.c
lib/SDLAudio/src/audio/mme/SDL_mmeaudio.c
lib/SDLAudio/src/audio/nas/SDL_nasaudio.c
lib/SDLAudio/src/audio/nto/SDL_nto_audio.c
lib/SDLAudio/src/audio/sun/SDL_sunaudio.c
lib/SDLAudio/src/audio/ums/SDL_umsaudio.c
lib/SDLAudio/src/audio/alsa/SDL_alsa_audio.c
lib/SDLAudio/src/audio/arts/SDL_artsaudio.c
lib/SDLAudio/src/audio/disk/SDL_diskaudio.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio_xbios.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio_dma8.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio_gsxb.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio_mcsn.c
lib/SDLAudio/src/audio/mint/SDL_mintaudio_stfa.c
lib/SDLAudio/src/audio/SDL_audio.c
lib/SDLAudio/src/audio/dmedia/SDL_irixaudio.c
lib/SDLAudio/src/audio/macrom/SDL_romaudio.c
lib/SDLAudio/src/audio/paudio/SDL_paudio.c
lib/SDLAudio/src/audio/riscos/SDL_drenderer.c
lib/SDLAudio/src/audio/windib/SDL_dibaudio.c
lib/SDLAudio/src/audio/windx5/SDL_dx5audio.c
lib/SDLAudio/src/audio/openbsd/SDL_openbsdaudio.c
lib/SDLAudio/src/audio/SDL_audiodev.c
lib/SDLAudio/src/audio/SDL_audiocvt.c
lib/SDLAudio/src/audio/SDL_audiomem.c
lib/SDLAudio/src/audio/SDL_mixer.c
lib/SDLAudio/src/SDL_error.c
[at@basalt mpeg4ip-1.3]$

at@solemn ~build/SDL-1.2.8 5 $ find src/audio -name '*.c'
src/audio/dc/SDL_dcaudio.c
src/audio/dc/aica.c
src/audio/dma/SDL_dmaaudio.c
src/audio/dsp/SDL_dspaudio.c
src/audio/esd/SDL_esdaudio.c
src/audio/mme/SDL_mmeaudio.c
src/audio/nas/SDL_nasaudio.c
src/audio/nto/SDL_nto_audio.c
src/audio/sun/SDL_sunaudio.c
src/audio/ums/SDL_umsaudio.c
src/audio/alsa/SDL_alsa_audio.c
src/audio/arts/SDL_artsaudio.c
src/audio/disk/SDL_diskaudio.c
src/audio/mint/SDL_mintaudio_xbios.c
src/audio/mint/SDL_mintaudio.c
src/audio/mint/SDL_mintaudio_dma8.c
src/audio/mint/SDL_mintaudio_gsxb.c
src/audio/mint/SDL_mintaudio_mcsn.c
src/audio/mint/SDL_mintaudio_stfa.c
src/audio/SDL_mixer_MMX.c
src/audio/SDL_mixer_m68k.c
src/audio/SDL_audio.c
src/audio/SDL_wave.c
src/audio/dmedia/SDL_irixaudio.c
src/audio/macosx/SDL_coreaudio.c
src/audio/macrom/SDL_romaudio.c
src/audio/paudio/SDL_paudio.c
src/audio/riscos/SDL_drenderer.c
src/audio/windib/SDL_dibaudio.c
src/audio/windx5/SDL_dx5audio.c
src/audio/openbsd/SDL_openbsdaudio.c
src/audio/SDL_audiodev.c
src/audio/SDL_audiocvt.c
src/audio/SDL_audiomem.c
src/audio/SDL_mixer_MMX_VC.c
src/audio/SDL_mixer.c
at@solemn ~build/SDL-1.2.8 5 $

Дублирование кода очевидно.  В mpeg4ip это так и было задумано?
То есть код модифицированный, или безобразие в чистом виде?