How to use original names when using find -exec?

Question

There are .mp4 files I want to convert.

$ find . -name '*.mp4'
./01.mp4
./02.mp4
./03.mp4

I expected to output files copy-01.mp4, copy-02.mp4 and copy-03.mp4 with this command.

find . -name '*.mp4' -exec ffmpeg -i {} -c copy -aspect 16:9 copy-{} ";"

But it failed with errors Unable to find a suitable output format for 'copy-'. I thought {} represents the file name, isn't it?

How can I use original file names when using -exec option of find?

The find version is:

$ find --version
find (GNU findutils) 4.4.2
Copyright (C) 2007 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Eric B. Decker, James Youngman, and Kevin Dalley.
Built using GNU gnulib version e5573b1bad88bfabcda181b9e0125fb0c52b7d3b
Features enabled: O_NOFOLLOW(disabled) LEAF_OPTIMISATION FTS() CBO(level=0)

This is xargs version.

xargs --version
xargs (GNU findutils) 4.4.2
Copyright (C) 2007 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Eric B. Decker, James Youngman, and Kevin Dalley.
Built using GNU gnulib version e5573b1bad88bfabcda181b9e0125fb0c52b7d3b

Result of ffmpeg

$ find * -type f -name '*.mp4' -exec ffmpeg -i {} -c copy -aspect 16:9 copy-{} ";"

# almost same outputs several times here.

ffmpeg version N-50911-g9efcfbe Copyright (c) 2000-2013 the FFmpeg developers
  built on Mar 13 2013 21:26:48 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil      52. 19.100 / 52. 19.100
  libavcodec     55.  0.100 / 55.  0.100
  libavformat    55.  0.100 / 55.  0.100
  libavdevice    54.  4.100 / 54.  4.100
  libavfilter     3. 45.103 /  3. 45.103
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '24.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42isomavc1
    creation_time   : 2012-11-01 13:42:12
    encoder         : HandBrake 0.9.8 2012071700
  Duration: 00:24:58.62, start: 0.000000, bitrate: 474 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x256, 341 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 180k tbc
    Metadata:
      creation_time   : 2012-11-01 13:42:12
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s
    Metadata:
      creation_time   : 2012-11-01 13:42:12

Answer 1

The proper way would be to make a bash script. The problem is the current directory prefix ./

If you really must you can do:

find * -type f -name '*.mp4' -exec ffmpeg -i {} -c copy -aspect 16:9 copy-{} ";"

Or if you have xargs:

find . -name '*.mp4' | xargs -L1 basename | xargs -L1 -I{} ffmpeg -i {} -c copy -aspect 16:9 copy-{}