title: ffmpeg can't stream to remote client
body: <p>I'm building a simple <code>ffmpeg</code> command line on my laptop to stream from its camera. The command line reads (verbose output at the botton):</p>
  
  <pre><code>host1&gt; ffmpeg -v verbose \
                -f dshow \
                -i video="Camera":audio="Microphone" \
                -r 30 -g 0 -vcodec h264 -acodec libmp3lame \
                -tune zerolatency \
                -preset ultrafast \
                -f mpegts udp://12.34.56.78:12345
  </code></pre>
  
  <p>Firstly, it works locally. I.e., I can view the output by using <code>ffplay</code> on the same host:</p>
  
  <pre><code>host1&gt; ffplay -hide_banner -v udp://12.34.56.78:12345
  </code></pre>
  
  <p>Now what is NOT working is when I do this from another machine in the same network. It shows a <code>nan</code> progress:</p>
  
  <pre><code>host2&gt; ffplay -hide_banner -v udp://12.34.56.78:12345
      nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0   
  </code></pre>
  
  <p>I used <code>ncat</code> to dump the raw content. But there's no output:</p>
  
  <pre><code>host2&gt;\ncat\ncat -v -u 12.34.56.78 12345
  Ncat: Version 5.59BETA1 ( http://nmap.org/ncat )
  Ncat: Connected to 12.34.56.78:12345.
  (...and nothing happen...)
  </code></pre>
  
  <p>Note that I can exclude firewall issues as I used <code>ncat</code> to communicate with each other across the wire <em>using the same port and protocol (UDP)</em>. This works and they can chat to each other:</p>
  
  <pre><code>host1&gt; ncat -l -u -p 12345
  host2&gt; ncat -u 12.34.56.78 12345
  </code></pre>
  
  <p>Any hint?</p>
  
  <p>I'm using Windows x64 with FFMPEG 64bit installed from <a href="http://ffmpeg.zeranoe.com/builds/" rel="nofollow">here</a>. Below is the Output of my ffmpeg command:</p>
  
  <pre><code>C:\ffmpeg\bin&gt;ffmpeg -v verbose -f dshow -i video="Integrated Camera":audio="Microphone (Realtek High Definition Audio)" -r 30 -g 0 -vcodec h264 -acodec libmp3lame -tune zerolatency -preset ultrafast -f mpegts udp://12.34.56.78:12345
  ffmpeg version N-66012-g97b8809 Copyright (c) 2000-2014 the FFmpeg developers
    built on Sep  1 2014 00:21:15 with gcc 4.8.3 (GCC)
    configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug -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-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-decklink --enable-zlib
    libavutil      54.  7.100 / 54.  7.100
    libavcodec     56.  1.100 / 56.  1.100
    libavformat    56.  3.100 / 56.  3.100
    libavdevice    56.  0.100 / 56.  0.100
    libavfilter     5.  0.103 /  5.  0.103
    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 : stereo
  Input #0, dshow, from 'video=Integrated Camera:audio=Microphone (Realtek High Definition Audio)':
    Duration: N/A, start: 171840.657000, bitrate: N/A
      Stream #0:0: Video: rawvideo, bgr24, 640x480, 30 fps, 30 tbr, 10000k tbn, 30 tbc
      Stream #0:1: Audio: pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
  Matched encoder 'libx264' for codec 'h264'.
  [graph 0 input from stream 0:0 @ 0000000000470aa0] w:640 h:480 pixfmt:bgr24 tb:1/10000000 fr:10000000/333333 sar:0/1 sws_param:flags=2
  [auto-inserted scaler 0 @ 0000000004326d00] w:iw h:ih flags:'0x4' interl:0
  [format @ 0000000004325a00] auto-inserting filter 'auto-inserted scaler 0' between the filter 'Parsed_null_0' and the filter 'format'
  [auto-inserted scaler 0 @ 0000000004326d00] w:640 h:480 fmt:bgr24 sar:0/1 -&gt; w:640 h:480 fmt:yuv444p sar:0/1 flags:0x4
  No pixel format specified, yuv444p for H.264 encoding chosen.
  Use -pix_fmt yuv420p for compatibility with outdated media players.
  [graph 1 input from stream 0:1 @ 0000000000460c20] tb:1/44100 samplefmt:s16 samplerate:44100 chlayout:0x3
  [audio format for output stream 0:1 @ 00000000004601a0] auto-inserting filter 'auto-inserted resampler 0' between the filter 'Parsed_anull_0' and the filter 'audio format for output stream 0:1'
  [auto-inserted resampler 0 @ 00000000004604a0] ch:2 chl:stereo fmt:s16 r:44100Hz -&gt; ch:2 chl:stereo fmt:s16p r:44100Hz
  [libx264 @ 000000000081bb20] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  [libx264 @ 000000000081bb20] profile High 4:4:4 Intra, level 3.0, 4:4:4 8-bit
  [mpegts @ 000000000081abe0] muxrate VBR, pcr every 3 pkts, sdt every 200, pat/pmt every 40 pkts
  Output #0, mpegts, to 'udp://12.34.56.78:12345':
    Metadata:
      encoder         : Lavf56.3.100
      Stream #0:0: Video: h264 (libx264), yuv444p, 640x480, q=-1--1, 30 fps, 90k tbn, 30 tbc
      Metadata:
        encoder         : Lavc56.1.100 libx264
      Stream #0:1: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p
      Metadata:
        encoder         : Lavc56.1.100 libmp3lame
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (rawvideo (native) -&gt; h264 (libx264))
    Stream #0:1 -&gt; #0:1 (pcm_s16le (native) -&gt; mp3 (libmp3lame))
  Press [q] to stop, [?] for help
  *** 1 dup!
  frame=  241 fps= 31 q=28.0 Lsize=    3439kB time=00:00:08.03 bitrate=3506.4kbits/s dup=1 drop=0
  video:3035kB audio:125kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 8.791966%
  Input file #0 (video=Integrated Camera:audio=Microphone (Realtek High Definition Audio)):
    Input stream #0:0 (video): 240 packets read (221184000 bytes); 240 frames decoded;
    Input stream #0:1 (audio): 16 packets read (1411200 bytes); 16 frames decoded (352800 samples);
    Total: 256 packets (222595200 bytes) demuxed
  Output file #0 (udp://12.34.56.78:12345):
    Output stream #0:0 (video): 241 frames encoded; 241 packets muxed (3108187 bytes);
    Output stream #0:1 (audio): 306 frames encoded (352512 samples); 307 packets muxed (128313 bytes);
    Total: 548 packets (3236500 bytes) muxed
  [libx264 @ 000000000081bb20] frame I:241   Avg QP:27.97  size: 12897
  [libx264 @ 000000000081bb20] mb I  I16..4: 100.0%  0.0%  0.0%
  [libx264 @ 000000000081bb20] coded y,u,v intra: 26.3% 0.5% 0.0%
  [libx264 @ 000000000081bb20] i16 v,h,dc,p: 19% 28% 21% 31%
  [libx264 @ 000000000081bb20] kb/s:3095.29
  [dshow @ 0000000000467720] real-time buffer[Integrated Camera] too full (90% of size: 3041280)! frame dropped!
  Received signal 2: terminating. (I pressed CTRL-C)
  </code></pre>