Using FFMPEG to extract video loses sync between sound and vision

[C E Macfarlane]

As per subject line, using this version of ffmpeg under Windows XP ...

ffmpeg version 2.2.3 Copyright (c) 2000-2014 the FFmpeg developers
  built on Jun 19 2014 20:24:25 with gcc 4.8.3 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enabl
e-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutl
s --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enabl
e-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libm
odplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-a
mrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschr
oedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libt
wolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --e
nable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-deckli
nk --enable-zlib

... and trying to extract a section of this ...

http://www.bbc.co.uk/programmes/b06z8cxd

... with the following command ...

FFMPEG -i CuirmCeltic-2016-1.mp4 -acodec copy -vcodec copy -ss 1211.5 -to
1465 Chieftains.mp4

... leads to a result where the sound is out of sync with the vision.  Can
anyone suggest a fix?

C E Macfarlane
www.macfh.co.uk/CEMH.html