title: ffmpeg : Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
body: <p>I'm experiencing troubles running ffmpeg on my synology. I'm trying to convert .avi video to mp4.</p>
  
  <p>Here is the command : </p>
  
  <p><code>ffmpeg -i vid20160623.avi -acodec libfaac -b:a 128k -vcodec mpeg4 -b:v 1200k -flags +aic+mv4 -f mp4 vid20160623.mp4</code></p>
  
  <p>And the logs : </p>
  
  <pre><code>ffmpeg version 2.7.1 Copyright (c) 2000-2015 the FFmpeg developers
    built with gcc 4.9.3 (crosstool-NG 1.20.0) 20150311 (prerelease)
    configuration: --prefix=/usr --incdir='${prefix}/include/ffmpeg' --arch=arm --target-os=linux --cross-prefix=/usr/local/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi- --enable-cross-compile --enable-optimizations --enable-pic --enable-gpl --enable-shared --disable-static --enable-version3 --enable-nonfree --enable-libfaac --enable-encoders --enable-pthreads --disable-bzlib --disable-protocol=rtp --disable-muxer=image2 --disable-muxer=image2pipe --disable-swscale-alpha --disable-ffserver --disable-ffplay --disable-devices --disable-bzlib --disable-altivec --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libmp3lame --disable-vaapi --disable-decoder=amrnb --disable-encoder=zmbv --disable-encoder=dca --disable-encoder=ac3 --disable-encoder=ac3_fixed --disable-encoder=eac3 --disable-decoder=dca --disable-decoder=eac3 --disable-decoder=truehd --cc=/usr/local/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-ccache-gcc
    libavutil      54. 27.100 / 54. 27.100
    libavcodec     56. 41.100 / 56. 41.100
    libavformat    56. 36.100 / 56. 36.100
    libavdevice    56.  4.100 / 56.  4.100
    libavfilter     5. 16.101 /  5. 16.101
    libswscale      3.  1.101 /  3.  1.101
    libswresample   1.  2.100 /  1.  2.100
    libpostproc    53.  3.100 / 53.  3.100
  Input #0, avi, from 'vid20160623.avi':
    Metadata:
      encoder         : MEncoder git-ab94fc6-4.4.3
    Duration: 00:20:18.07, start: 0.000000, bitrate: 1197 kb/s
      Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 624x352 [SAR 1:1 DAR 39:22], 1056 kb/s, 25 fps, 23.98 tbr, 25 tbn, 23.98 tbc
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16p, 128 kb/s
  Output #0, mp4, to vid20160623.mp4':
    Metadata:
      encoder         : MEncoder git-ab94fc6-4.4.3
      Stream #0:0: Video: mpeg4, none, q=2-31, 128 kb/s, SAR 351:352 DAR 0:0, 23.98 fps
      Metadata:
        encoder         : Lavc56.41.100 mpeg4
      Stream #0:1: Audio: aac, 0 channels, 128 kb/s
      Metadata:
        encoder         : Lavc56.41.100 libfaac
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (mpeg4 (native) -&gt; mpeg4 (native))
    Stream #0:1 -&gt; #0:1 (mp3 (native) -&gt; aac (libfaac))
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
  </code></pre>
  
  <p>I tried to reduce b:a and b:v but it did not work.</p>
  
  <p>Any help will be welcome.</p>