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<li><a class="reference internal" href="#">FFmpeg piping</a><ul>
<li><a class="reference internal" href="#piping-data-to-packager">Piping data to packager</a></li>
<li><a class="reference internal" href="#encoding-capture-command">Encoding / capture command</a><ul>
<li><a class="reference internal" href="#camera-capture">Camera capture</a></li>
<li><a class="reference internal" href="#rtp-input">RTP input</a></li>
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<div class="section" id="ffmpeg-piping">
<h1>FFmpeg piping<a class="headerlink" href="#ffmpeg-piping" title="Permalink to this headline"></a></h1>
<p>We can use <em>FFmpeg</em> to redirect / pipe input not supported by <em>packager</em>
to <em>packager</em>, for example, input from webcam devices, or rtp input. The concept
depicted here can be applied to other <em>FFmpeg</em> supported device or protocols.</p>
<div class="section" id="piping-data-to-packager">
<h2>Piping data to packager<a class="headerlink" href="#piping-data-to-packager" title="Permalink to this headline"></a></h2>
<p>There are two options to pipe data to packager.</p>
<ul>
<li><p class="first">UDP socket</p>
<blockquote>
<div><p><em>FFmpeg</em> supports writing to a UDP socket and <em>packager</em> supports reading
from UDP sockets:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ packager &#39;input=udp://127.0.0.1:40000,...&#39; ...
$ ffmpeg ... -f mpegts udp://127.0.0.1:40000
</pre></div>
</div>
<p>VP9 cannot be carried in mpegts. Another container, e.g. webm needs to be
used when outputs VP9. In this case, transcoding has to be started after
starting packager as the initialization segment is only transmitted in the
beginning of WebM output.</p>
</div></blockquote>
</li>
<li><p class="first">pipe</p>
<blockquote>
<div><p>Similarily, pipe is also supported in both <em>FFmpeg</em> and <em>packager</em>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ mkfifo pipe1
$ packager &#39;input=pipe1,...&#39; ... --io_block_size 65536
$ ffmpeg ... -f mpegts pipe: &gt; pipe1
</pre></div>
</div>
</div></blockquote>
</li>
</ul>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Option -io_block_size 65536 tells packager to use an io_block_size of 65K
for threaded io file. This is necessary when using pipe as reading from pipe
blocks until the specified number of bytes, which is specified in
io_block_size for threaded io file, thus the value of io_block_size cannot
be too large.</p>
</div>
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<div class="section" id="encoding-capture-command">
<h2>Encoding / capture command<a class="headerlink" href="#encoding-capture-command" title="Permalink to this headline"></a></h2>
<div class="section" id="camera-capture">
<h3>Camera capture<a class="headerlink" href="#camera-capture" title="Permalink to this headline"></a></h3>
<p>Refer to <a class="reference external" href="https://trac.ffmpeg.org/wiki/Capture/Webcam">FFmpeg Capture/Webcam</a>
on how to use <em>FFmpeg</em> to capture webmcam inputs.</p>
<p>The example assumes Mac OS X 10.7 (Lion) or later. It captures from the default
audio / video devices on the machine:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ ffmpeg -f avfoundation -i &quot;default&quot; -f mpegts udp://127.0.0.1:40000
</pre></div>
</div>
<p>The command starts only after packager starts.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">After encoding starts, monitor encoding speed carefully. It should always be
1x and above. If not, adjust the encoding parameters to recude it.</p>
</div>
</div>
<div class="section" id="rtp-input">
<h3>RTP input<a class="headerlink" href="#rtp-input" title="Permalink to this headline"></a></h3>
<p>Assume there is an RTP input described by <cite>saved_sdp_file</cite>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ ffmpeg -protocol_whitelist &quot;file,rtp,udp&quot; -i saved_sdp_file -vcodec h264 \
-tune zerolatency -f mpegts udp://127.0.0.1:40000
</pre></div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>For testing, you can generate an RTP input from a static media file:</p>
<div class="last highlight-default"><div class="highlight"><pre><span></span>$ ffmpeg -re -stream_loop 100 -i &lt;static.mp4&gt; -vcodec copy -acodec \
copy -f rtp rtp://239.255.0.1:1234 -sdp_file saved_sdp_file
</pre></div>
</div>
</div>
<p>The command starts only after packager starts.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">After encoding starts, monitor encoding speed carefully. It should always be
1x or above. If not, adjust the encoding parameters to increase it.</p>
</div>
</div>
</div>
<div class="section" id="example-packaging-command-in-dash">
<h2>Example packaging command in DASH<a class="headerlink" href="#example-packaging-command-in-dash" title="Permalink to this headline"></a></h2>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ packager \
&#39;in=udp://127.0.0.1:40000,stream=audio,init_segment=live_cam_audio.mp4,segment_template=live_cam_audio_$Number$.m4s&#39; \
&#39;in=udp://127.0.0.1:40000,stream=video,init_segment=live_cam_video.mp4,segment_template=live_cam_video_$Number$.m4s&#39; \
--mpd_output live_cam.mpd
</pre></div>
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