title: Merge webm video with audio
body: <p>I am using below command to merge an audio with <strong>webm video</strong>.But the c</p>
  
  <pre><code>command = new String[]{"-i", inputvideoFileAbsolutePath, "-i", inputaudioFileAbsolutePath, "-c:v", "copy", "-c:a", "aac", "-map", "0:v:0", "-map", "1:a:0", "-shortest", outputFileAbsolutePath};
  </code></pre>
  
  <p>where outputFileAbsolutePath extension is mp4.</p>
  
  <p>But the command fails with below error.However command seems to work fine with other input video formats(mp4,avi,mov,3gp).Why am i getting this error with webm video and how can i resolve it</p>
  
  <p>Main error-</p>
  
  <blockquote>
    <p>Could not write header for output file #0 (incorrect codec parameters
    ?): Invalid argument</p>
  </blockquote>
  
  <p>Complete error-</p>
  
  <pre><code> FAILED with output : ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers
                                                                                              built with gcc 4.8 (GCC)
                                                                                              configuration: --target-os=linux
      --cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi-
      --arch=arm --cpu=cortex-a8 --enable-runtime-cpudetect --sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot
      --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-fontconfig --enable-pthreads --disable-debug --disable-ffserver --enable-version3 --enable-hardcoded-tables --disable-ffplay --disable-ffprobe --enable-gpl --enable-yasm --disable-doc --disable-shared --enable-static --pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/vagrant/SourceCode/ffmpeg-android/build/armeabi-v7a --extra-cflags='-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include
      -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all' --extra-ldflags='-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib
      -Wl,-z,relro -Wl,-z,now -pie' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=                                                                           libavutil      55. 17.103 / 55. 17.103
                                                                                              libavcodec     57. 24.102 / 57. 24.102
                                                                                              libavformat    57. 25.100 / 57. 25.100
                                                                                              libavdevice    57.  0.101 / 57.  0.101
                                                                                              libavfilter     6. 31.100 /  6. 31.100
                                                                                              libswscale      4.  0.100 /  4.  0.100
                                                                                              libswresample   2.  0.101 /  2.  0.101
                                                                                              libpostproc    54.  0.100 / 54.  0.100
                                                                                            Input #0, matroska,webm, from '/storage/emulated/0/Download/small.webm':
                                                                                              Metadata:
                                                                                                encoder         : Lavf53.17.0
                                                                                              Duration: 00:00:05.57, start: 0.000000, bitrate: 329 kb/s
                                                                                                Stream #0:0: Video: vp8, yuv420p, 560x320, SAR 1:1 DAR 7:4, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
                                                                                                Stream #0:1(eng): Audio: vorbis, 48000 Hz, mono, fltp (default)
                                                                                            Guessed Channel Layout for  Input Stream #1.0 : stereo
                                                                                            Input #1, wav, from '/storage/emulated/0/Download/out.wav':
                                                                                              Metadata:
                                                                                                encoder         : Lavf57.76.100
                                                                                              Duration: 00:00:33.88, bitrate: 1411 kb/s
                                                                                                Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels, s16, 1411 kb/s
                                                                                            [mp4 @ 0xb61adc00] Could not find tag for codec vp8 in stream #0, codec not currently supported in container
                                                                                            Output #0, mp4, to '/storage/emulated/0/Movies/merge_video2.mp4':
                                                                                              Metadata:
                                                                                                encoder         : Lavf57.25.100
                                                                                                Stream #0:0: Video: vp8, yuv420p, 560x320 [SAR 1:1 DAR 7:4], q=2-31, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
                                                                                                Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s
                                                                                                Metadata:
                                                                                                  encoder         : Lavc57.24.102 aac
                                                                                            Stream mapping:
                                                                                              Stream #0:0 -&gt; #0:0 (copy)
                                                                                              Stream #1:0 -&gt; #0:1 (pcm_s16le (native) -&gt; aac (native))
                                                                                            Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
                                                                                            [aac @ 0xb61fdc00] Qavg: nan
  </code></pre>