title: Webm streaming issue with ffmpeg/ffserver
body: <p>I am trying to play the stream from ip camera in the browser. I am using ffmpeg  and ffserver stack for that (both 2.4.2). </p>
  
  <p>For now I can easily play video stream in browser using flash. But I would like to have ability to play it in native html5 player. And I need webm format to do that.</p>
  
  <p>ffserver config snippet:</p>
  
  <pre><code> &lt;Feed 0_webm.ffm&gt;
  File /tmp/0_webm.ffm
  FileMaxSize 5M
  ACL allow localhost
  &lt;/Feed&gt;
  
  &lt;Stream 0.webm&gt;
  Feed 0_webm.ffm
  Format webm
  NoAudio
  &lt;/Stream&gt;
  
  &lt;Stream test2.swf&gt;
  Feed feed2.ffm
  Format swf
  VideoCodec flv
  VideoFrameRate 30
  VideoBufferSize 50000
  VideoBitRate 100
  VideoQMin 1
  VideoQMax 5
  VideoSize 352x288
  PreRoll 0
  Noaudio
  &lt;/Stream&gt;
  </code></pre>
  
  <p>I execute this command to get stream from camera and pass it to a client through ffserver:</p>
  
  <pre><code>ffmpeg -rtsp_transport tcp -i rtsp://admin:admin@192.168.10.76:80 -vcodec libvpx r 10 -f webm http://localhost:8090/0_webm.ffm
  </code></pre>
  
  <p>But get "Broken pipe" error message (full ffmeg output):</p>
  
  <pre><code>ffmpeg version 2.4.2 Copyright (c) 2000-2014 the FFmpeg developers
    built on Oct  6 2014 17:33:05 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
    configuration: --prefix=/opt/ffmpeg --libdir=/opt/ffmpeg/lib/ --enable-shared --enable-avresample --disable-stripping --enable-gpl --enable-version3 --enable-runtime-cpudetect --build-suffix=.ffmpeg --enable-postproc --enable-x11grab --enable-libcdio --enable-vaapi --enable-vdpau --enable-bzlib --enable-gnutls --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libfaac --enable-libvo-aacenc --enable-nonfree --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfdk_aac --enable-libopus --enable-pthreads --enable-zlib --enable-libvpx --enable-libfreetype --enable-libpulse --enable-debug=3
    libavutil      54.  7.100 / 54.  7.100
    libavcodec     56.  1.100 / 56.  1.100
    libavformat    56.  4.101 / 56.  4.101
    libavdevice    56.  0.100 / 56.  0.100
    libavfilter     5.  1.100 /  5.  1.100
    libavresample   2.  1.  0 /  2.  1.  0
    libswscale      3.  0.100 /  3.  0.100
    libswresample   1.  1.100 /  1.  1.100
    libpostproc    53.  0.100 / 53.  0.100
  Guessed Channel Layout for  Input Stream #0.1 : mono
  Input #0, rtsp, from 'rtsp://admin:admin@192.168.10.76:80':
    Metadata:
      title           : RTSP Session/2.0
    Duration: N/A, start: 0.000000, bitrate: 128 kb/s
      Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
      Stream #0:1: Audio: pcm_alaw, 16000 Hz, 1 channels, s16, 128 kb/s
  [swscaler @ 0xcf97a0] deprecated pixel format used, make sure you did set range correctly
  [libvpx @ 0xd86fc0] v1.3.0
  Output #0, webm, to 'http://localhost:8090/0_webm.ffm':
    Metadata:
      title           : RTSP Session/2.0
      encoder         : Lavf56.4.101
      Stream #0:0: Video: vp8 (libvpx), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 200 kb/s, 10 fps, 1k tbn, 10 tbc
      Metadata:
        encoder         : Lavc56.1.100 libvpx
      Stream #0:1: Audio: vorbis (libvorbis), 16000 Hz, mono, fltp
      Metadata:
        encoder         : Lavc56.1.100 libvorbis
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (h264 (native) -&gt; vp8 (libvpx))
    Stream #0:1 -&gt; #0:1 (pcm_alaw (native) -&gt; vorbis (libvorbis))
  Press [q] to stop, [?] for help
  av_interleaved_write_frame(): Broken pipe
      Last message repeated 1 times
  frame=    2 fps=0.0 q=0.0 Lsize=      40kB time=00:00:00.23 bitrate=1371.2kbits/s    
  video:36kB audio:1kB subtitle:0kB other streams:0kB global headers:3kB muxing overhead: 7.514220%
  Conversion failed!
  </code></pre>
  
  <p>If I run the same command without -f webm, I get no error and it looks like working. But in this case I can't play it in browser (Chrome for instance).</p>
  
  <p>Does anybody know how to fix "Broken pipe issue"? Will be happy to get any your help or advises. Thanks in advance.</p>