/usr/share/avconv/ is in libav-tools 6:9.11-2ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/avconv/libvpx-1080p.avpreset
/usr/share/avconv/libvpx-1080p50_60.avpreset
/usr/share/avconv/libvpx-360p.avpreset
/usr/share/avconv/libvpx-720p.avpreset
/usr/share/avconv/libvpx-720p50_60.avpreset
/usr/share/avconv/libx264-baseline.avpreset
/usr/share/avconv/libx264-fast.avpreset
/usr/share/avconv/libx264-fast_firstpass.avpreset
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/usr/share/avconv/libx264-ipod640.avpreset
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/usr/share/avconv/libx264-medium_firstpass.avpreset
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/usr/share/avconv/libx264-ultrafast.avpreset
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