[FFmpeg-user] .png transparent watermark without background

[milad arabi]

hi all
i have logo.png file,it doesn't have background,but in output file ffmpeg
set white background watermark.

is it possible set transparent watermark without background?

i use ffmpeg version N-48886-g5ce023b Copyright (c) 2000-2013 the FFmpeg
developers
  built on Jan 14 2013 19:16:33 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls
--enab
le-libass --enable-libbluray --enable-libcaca --enable-libfreetype
--enable-libg
sm --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --e
nable-libopenjpeg --enable-libopus --enable-librtmp
--enable-libschroedinger --e
nable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc
--en
able-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264
--enable
-libxavs --enable-libxvid --enable-zlib --enable-filter=frei0r