title: FFplay: WASAPI can't initialize audio client (FFmpeg 3.4 binaries)
body: <p>I am trying to playback a stream that is multicasted over RTP using ffplay on Windows 7 64 bits.
  The computer that serves the audio over RTP runs:</p>
  
  <pre><code>ffmpeg -re -f dshow -audio_buffer_size 15 -ac 1 -i audio="Mic in at front Mic-in (Realtek" -ar 8k -acodec pcm_alaw -vn -f rtp rtp://127.0.0.1:5000
  </code></pre>
  
  <p>The client runs:</p>
  
  <pre><code>ffplay rtp://127.0.0.1:5000
  </code></pre>
  
  <p>While this was working correctly in release 3.3, release 3.4 fails with this error:</p>
  
  <pre><code>SDL_OpenAudio (1 channels, 8000 Hz): WASAPI can't initialize audio client: CoInitialize has not been called.
  
  No more combinations to try, audio open failed
  Failed to open file 'rtp://127.0.0.1:5000' or configure filtergraph
  </code></pre>
  
  <p>Anyone has an idea of whats going on ?</p>
  
  <p>Thanks</p>
  
  <p><strong>UPDATE #1:</strong></p>
  
  <p>A workaround is to specify an alternate output driver.
  Set SDL_AUDIODRIVER environment variable value to the driver you want to use.
  Under windows 7, <em>directsound</em> and <em>winmm</em> both solved my issue.</p>