Bonjour,

J'aimerai pouvoir utiliser ffmpeg pour couper une video et en prendre juste 30sec et par la même occasion la convertir en flv
J'ai vu 2 lignes de commande avec ffmpeg du style :
pour couper, c'était sur ce forum :
ffmpeg -vcodec copy -ss 00:00:10 -t 00:00:40 -i $i ./coupe/$i
#les options :

#La je coupe la vidéo en une vidéeo de 30 sec débutant à la 10ème sec 
#-vcodec copy => copy direct du flux video sans encodage
#-i => fichier d'entré
#-ss => position de départ
#-t => durée
et pour la conversion en flv :
ffmpeg -i video.avi -ar 22050 -ab 32 -f flv -s 320×240 video.flv
je souhaite faire cela sur un fichier .MTS qui est un format Mpeg HD sorti par ma camera

je teste l'encodage en flv voici ce que j'obtiens :
ffmpeg -i ./test_sony_nx5.MTS -ar 22050 -ab 32000 -f flv -s xga video.flv
FFmpeg version 0.6.90-rc0, Copyright (c) 2000-2011 the FFmpeg developers
  built on Apr 11 2011 20:49:15 with gcc 4.6.0 20110331 (Red Hat 4.6.0-2)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --enable-libdc1394 --enable-libdirac --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  libavutil    50. 40. 0 / 50. 40. 0
  libavcodec   52.117. 0 / 52.117. 0
  libavformat  52.104. 0 / 52.104. 0
  libavdevice  52.  4. 0 / 52.  4. 0
  libavfilter   1. 76. 0 /  1. 76. 0
  libswscale    0. 13. 0 /  0. 13. 0
  libpostproc  51.  2. 0 / 51.  2. 0
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 3 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported channel configuration (0)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 1 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 12 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 4 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (13)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (13)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (14)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (0)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 1 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (3)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (14)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (13)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 6 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (2)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
    Last message repeated 10 times
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (2)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (14)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (13)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] unsupported sample rate (15)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)

.
.
.
    Last message repeated 2 times
[pcm_bluray @ 0x1e915e0] unsupported sample rate (13)
[pcm_bluray @ 0x1e915e0] unsupported sample depth (0)
[pcm_bluray @ 0x1e915e0] PCM packet too small
[aac @ 0x23725e0] Input buffer exhausted before END element found
Error while decoding stream #0.1
[aac @ 0x23725e0] Reserved bit set.
Error while decoding stream #0.1
[aac @ 0x23725e0] channel element 0.0 is not allocated
Error while decoding stream #0.1
[aac @ 0x23725e0] More than one AAC RDB per ADTS frame is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[aac @ 0x23725e0] Error decoding AAC frame header.
Error while decoding stream #0.1
[aac @ 0x23725e0] Reserved bit set.
Error while decoding stream #0.1
[aac @ 0x23725e0] Invalid Predictor Reset Group.
Error while decoding stream #0.1
[aac @ 0x23725e0] Error decoding AAC frame header.
Error while decoding stream #0.1
[aac @ 0x23725e0] More than one AAC RDB per ADTS frame is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[aac @ 0x23725e0] Error decoding AAC frame header.
Error while decoding stream #0.1
[aac @ 0x23725e0] Reserved bit set.
Error while decoding stream #0.1
[aac @ 0x23725e0] Invalid Predictor Reset Group.
Error while decoding stream #0.1
Error while decoding stream #0.1s
    Last message repeated 1 times
[aac @ 0x23725e0] channel element 2.0 is not allocated
Error while decoding stream #0.1
[aac @ 0x23725e0] Reserved bit set.
Error while decoding stream #0.1
[aac @ 0x23725e0] More than one AAC RDB per ADTS frame is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[aac @ 0x23725e0] Error decoding AAC frame header.
Error while decoding stream #0.1
[aac @ 0x23725e0] Invalid Predictor Reset Group.
Error while decoding stream #0.1
[aac @ 0x23725e0] Reserved bit set.
Error while decoding stream #0.1
Error while decoding stream #0.1s
    Last message repeated 1 times
Input stream #0.1 frame changed from rate:0 fmt:s32 ch:0 to rate:96000 fmt:s16 ch:8
Resampling with input channels greater than 2 unsupported.
Can not resample 8 channels @ 96000 Hz to 0 channels @ 22050 Hz
et si je veux simplement couper, voici ce que j'obtiens :
ffmpeg -vcodec copy -ss 00:00:10 -t 00:00:40 -i ./test_sony_nx5.MTS ./test.avi
FFmpeg version 0.6.90-rc0, Copyright (c) 2000-2011 the FFmpeg developers
  built on Apr 11 2011 20:49:15 with gcc 4.6.0 20110331 (Red Hat 4.6.0-2)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --enable-libdc1394 --enable-libdirac --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  libavutil    50. 40. 0 / 50. 40. 0
  libavcodec   52.117. 0 / 52.117. 0
  libavformat  52.104. 0 / 52.104. 0
  libavdevice  52.  4. 0 / 52.  4. 0
  libavfilter   1. 76. 0 /  1. 76. 0
  libswscale    0. 13. 0 /  0. 13. 0
  libpostproc  51.  2. 0 / 51.  2. 0
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 3 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported channel configuration (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 1 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 12 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 4 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (13)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (13)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (14)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 1 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (3)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (14)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (13)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 6 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (2)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 10 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (2)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (14)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (13)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (15)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (13)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] unsupported sample rate (3)
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
[pcm_bluray @ 0x1dc45e0] PCM packet too small
[pcm_bluray @ 0x1dc45e0] unsupported sample depth (0)
    Last message repeated 2 times
[pcm_bluray @ 0x1dc45e0] PCM packet too small

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 50.00 (50/1)
Input #0, mpegts, from './test_sony_nx5.MTS':
  Duration: 00:01:14.39, start: 1.000033, bitrate: 23828 kb/s
  Program 1 
    Stream #0.0[0x1011]: Video: h264 (High), yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 50 fps, 50 tbr, 90k tbn, 50 tbc
    Stream #0.1[0x1100]: Audio: aac, 0 channels, s32, 767 kb/s
Incompatible sample format 's32' for codec 'mp2', auto-selecting format 's16'
[NULL @ 0x1dc5470] Requested sampling rate unsupported using closest supported (16000)
[mp2 @ 0x1dc5470] encoding 0 channel(s) is not allowed in mp2
Output #0, avi, to './test.avi':
    Stream #0.0: Video: libx264, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], q=2-31, 90k tbn, 25 tbc
    Stream #0.1: Audio: mp2, 16000 Hz, 0 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Error while opening encoder for output stream #0.1 - maybe incorrect parameters such as bit_rate, rate, width or height
Une idée ??
Je ne sais pas pour ffmeg, mais tu peux utiliser avidemux pour faire cela (dans dépot rpmfusion)