title: How to convert AV_SAMPLE_FMT_S16 to AV_SAMPLE_FMT_S16P?
body: <p>I use ffmpeg to decode audio and use libmp3lame to encode it into mp3. As libmp3lame inside ffmpeg needs S16P instead of S16, I have to convert audio samples.</p>
  
  <p>I tried using swr_convert but everytime I get a random crash. I started to have doubt if swr_convert accepts S16 as input or not.</p>
  
  <p>So, how can I convert audio samples from AV_SAMPLE_FMT_S16 to AV_SAMPLE_FMT_S16P?</p>